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Copyright © 2007 FindBestStuff

Human Evolution

FIFTH
EDITION

HUMAN
EVOLUTION: AN
ILLUSTRATED
INTRODUCTION
Roger Lewin

© 1984, 1989, 1993, 1999, 2005 by Blackwell Publishing Ltd
350 Main Street, Malden, MA 02148-5020, USA
108 Cowley Road, Oxford OX4 1JF, UK
550 Swanston Street, Carlton, Victoria 3053, Australia
The right of Roger Lewin to be identified as the Author of this Work has been asserted in
accordance with the UK Copyright, Designs, and Patents Act 1988
...
No part of this publication may be reproduced, stored in a retrieval system, or
transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or
otherwise, except as permitted by the UK Copyright, Designs, and Patents Act 1988, without the
prior permission of the publisher
...

Human evolution : an illustrated introduction / Roger Lewin
...

p
...

Includes bibliographical references and index
...
: alk
...
Human evolution
...
Title
...
L49 2005
599
...

Set in 9/111/2pt Meridien
by Graphicraft Limited, Hong Kong
Printed and bound in the United Kingdom
by William Clowes Ltd, Beccles, Suffolk
The publisher’s policy is to use permanent paper from mills that operate a sustainable forestry
policy, and which has been manufactured from pulp processed using acid-free and elementary
chlorine-free practices
...

For further information on
Blackwell Publishing, visit our website:
http://www
...
com

CONTENTS

Preface
...
1
Unit 1: Our Place in Nature
...
7
Unit 3: Historical Views
...
18
Unit 5: The Physical Context of Evolution
...
30
PART TWO: BACKGROUND TO HUMAN
EVOLUTION
...
39
Unit 8: Systematics: Morphological and Molecular
...
56
Unit 10: Primate Heritage
...
67
Unit 11: Bodies, Size, and Shape
...
75
Unit 13: Bodies, Behavior, and Social Structure
...
87
PART FOUR: HOMININ BEGINNINGS
...
95
Unit 16: Origin of the Hominoidea
...
109
Unit 18: Jaws and Teeth
...
121

PART FIVE: THE HOMININ ADAPTATION
...
131
Unit 21: Early Homo
...
146
Unit 23: Early Tool Technologies
...
157
Unit 24: The Changing Position of Homo erectus
...
166
Unit 26: Hunter or Scavenger?
...
177
Unit 27: The Neanderthal Enigma
...
187
Unit 29: Genetic Evidence
...
208
PART EIGHT: THE HUMAN MILIEU
...
217
Unit 32: The Evolution of Language
...
229
PART NINE: NEW WORLDS
...
239
Unit 35: The Origin of Agriculture and the First
Villagers
...
253
Index
...
For instance, in the preface to the
previous edition I wrote, “The five years since the third edition of Human Evolution: An Illustrated Introduction have been
an extraordinarily productive time for paleoanthropology,”
not least because of the number of new species of early
humans that had been discovered
...
Since 1999 four
new species of hominin have been announced
...
)
Of the four new species, three have been assigned to new
genera
...
One of them was
found in Chad, rather than in East Africa
...
5 million years old, from Kenya),
has the kind of flat face that was thought to have arisen much
later in hominin history
...

Description and discussion of these finds represents one of
the major changes from the fourth edition, which involves a
thorough reorganization of units dealing with this period
...
* The debate over the mode of
the origin of modern humansawas it a single, recent origin
or global and gradualacontinues, but new genetic evidence
adds further support to the notion of a single, recent origin
...
The announcement, in mid-2003, of a 160,000year-old specimen of early Homo sapiens from Ethiopia also
strengthens the argument for a single, recent origin, in
Africa
...
Was it recent and dramatic, or more gradual, with deeper roots? Evidence for the latter is growing
...

The trend continues in paleoanthropology from viewing
human evolution as having occurred under special circumstances to accepting humans as animals and having evolved
in ways similar to other animals
...
This is recognized
here in discussions of life-history factors and the impact of
body size and shape
...
Previously thought to
be 25,000 years old, the Lake Mungo cranium is now shown
to be 42,000 years old, and tools at a nearby site are close to
50,000 years old, establishing a relatively early occupation of
the continent
...
That change in human development appears
to have occurred later in the lineage
...

Obviously, paleoanthropology continues to be a healthy,
robust science, embracing new facts and reinterpretations
in the search for the pattern of human history
...
As I noted in the previous edition, “Armed with this knowledge, the student is
better prepared to assess what is being said in one debate or
another in the science
...
The
responsibility for the final product is, of course, mine
...
Research on the origin of modern humans
continues to dominate paleoanthropology
...


Roger Lewin
Cambridge, Massachusetts

PART 1

HUMAN
EVOLUTION IN
PERSPECTIVE
1
2
3
4
5
6

Our Place in Nature
Human Evolution as Narrative
Historical Views
Modern Evolutionary Theory
The Physical Context of Evolution
Extinction and Patterns of Evolution

OUR PLACE
IN NATURE

1

The Darwinian revolution forced people to face the fact that humans
are part of nature, not above nature
...
Only since the latter part of the twentieth century have
anthropologists fully embraced naturalistic explanations of our
special qualities
...
The book, which appeared a little
more than three years after Darwin’s Origin of Species, was
based principally on evidence from comparative anatomy
and embryology among apes and humans
...
) Huxley’s conclusionathat humans share a close
evolutionary relationship with the great apes, particularly
the African apesawas a key element in a revolution in the
history of Western philosophy: humans were to be seen as
being a part of nature, no longer as apart from nature
...
“No one is more strongly convinced than I am of the
vastness of the gulf between
...
stands raised upon
it as on a mountain top, far above the level of his humble fellows, and transfigured from his grosser nature by reflecting,
here and there, a ray from the infinite source of truth
...
One
difference between the two eras was that, after Darwin, naturalistic explanations had to account not only for the human
physical form but also for humans’ exceptional intellectual,
spiritual, and moral qualities
...

As a result, said the late archeologist Glynn Isaac, “Understanding the literature on human evolution calls for the
recognition of special problems that confront scientists who
report on this topic
...
“Regardless of how
scientists present them, accounts of human origins are read
as replacement materials for Genesis
...
do more than
cope with curiosity, they have allegorical content, and they
convey values, ethics and attitudes
...
As we
shall see, that “place” has long been regarded as being special
in some sense
...
The first revolution occurred three
centuries earlier, when Nicholaus Copernicus replaced the
geocentric model of the universe (see figure 1
...
Although the Copernican revolution
deposed humans from being the cosmic center of all of God’s
creation and transformed humans into the occupants of a
small planet cycling in a vast universe, humans nevertheless
remained the pinnacle of God’s works
...

This pursuitaknown as natural philosophyapositioned
science and religion in close harmony, with the remarkable
design so clearly manifested in creatures great and small
being seen as evidence of God’s hand
...
2 The anthropomorpha of Linnaeus: In the mideighteenth century, when Linnaeus compiled his Systema Naturae,
Western scientific knowledge about the apes of Asia and Africa was
sketchy at best
...
Here,
produced from a dissertation of Linnaeus’ student Hoppius, are four
supposed “manlike apes,” some of which became species of Homo in
Linnaeus’ Systema Naturae
...


Figure 1
...
The Earth was seen as the center
of the universe, with the Sun, Moon, stars, and planets fixed in
concentric crystalline spheres circling it
...
This continuum
aknown as the Chain of Beingawas not a statement of
evolutionary relationships between organisms, reflecting
historical connections and evolutionary derivations
...
”
Powerful though it was, the theory faced problemsa
specifically, some unexplained gaps
...
Another separated humans and apes
...

For instance, some apes were “known” to walk upright, to
carry off humans for slaves, and even to produce offspring
after mating with humans
...

This perception of the natural world inevitably became
encompassed within the formal classification system, which
was developed by Carolus Linnaeus in the mid-eighteenth
century
...
(See figure 1
...
)
“Linnaeus worked with a theory that anticipated such creatures,” noted Gould; “since they should exist anyway, imperfect evidence becomes acceptable
...
This human weakness has always operated in scienceain all sciencesaand
always will
...

Geological ideas had been changing as well
...
Following each catastrophe, the Earth was repopulated in a wave of creation
...
(See also unit 6
...
James Hutton, a Scotsman, seeded the ideas of Uniformitarianism, but it was Charles Lyell, another Scotsman,
who solidified the ideas, effectively becoming the founder of
modern geology
...

Lyell published his work in three volumes, The Principles of
Geology, the first of which appeared in 1830
...
This was important for Charles Darwin’s development of the theory of natural selection, which is based on the
accumulation of small changes over long periods of time
...
(See figure 1
...
) Interestingly, although the
advent of the evolutionary era brought an enormous shift in
intellectual perceptions of the origin of humankind, many
elements concerning the nature of mankind remained unassailed
...
And
the gradation from the so-called “lower” races to “higher”
races that had been part of the Chain of Being was now
explained by the process of evolution
...
“Some
developed into masters of the world at an incredible speed
...
and the existing Australian aborigines
lagged far behind, not much advanced beyond the stages of
Neanderthal man
...
(See, for example, figure 1
...
)
In other words, inequality of racesawith blacks on the
bottom and whites on the topawas explained away as the
natural order of things: before 1859 as the product of God’s
creation, and after 1859 as the product of natural selection
...
3 Two great intellectual revolutions: In the midsixteenth century the Polish mathematician Nicolaus Copernicus
proposed a heliocentric rather than a geocentric view of the
universe
...
” Three centuries later, in
1859, Charles Darwin further changed Man’s view of himself,
arguing that humans were a part of nature, not apart from nature
...
“Much of evolution looks as if it
had been planned to result in man, and in other animals and
plants to make the world a suitable place for him to dwell in,”
observed Robert Broom in 1933
...
)

EVOLUTION AS PROGRESS
Evolution as progressathe inexorable improvement to more
complex, more intelligent lifeahas always been a seductive
notion
...
The notion of progress as a driving ethos of naturea
and societyahas been a characteristic of Western philosophy,

6 Part One: Human Evolution in Perspective
White
Mongoloid
Melanesian-Papuan
Australian
Hapalidae
Cebidae
Tarsius
Lorisdae
Lemuridae
Semnopiths
Cercopiths

Negrito
Bushman
Congo Negrillo
African Negro
Chimpanzee
Coastal Gorilla
Mountain Gorilla
Orangutan
Siamang
Gibbon

Sinanthropus
Neanderthal

Pleistocene

Rhodesian

Swanscombe
Eoanthropus

Australopithecinae
Pithecanthropus

Pliocene

Dryopithecinae
Platyrrhini
Miocene
Cerocopithecidae
Tarsioidea

pologists have viewed the natural world in which we evolved
...
In 1958, for instance,
Julian Huxley, grandson of Thomas Henry, suggested that
mankind’s special intellectual and social qualities should be
recognized formally by assigning Homo sapiens to a new grade,
the Psychozoan
...
”
The ultimate issue is “the long-held view that humans are
unique, a totally new type of organism,” as Cambridge University’s Robert Foley points out
...
” That, of course, is
untrue, but it has been only since the latter part of the twentieth century that paleoanthropology has become fully committed to finding purely biological explanations for the origin
of the undoubtedly special features possessed by Homo
sapiens
...


Oligocene
Propliopithecus

Lemuroidea

Eocene

Figure 1
...
Here,
the supposed ascendancy of the “white” races is shown explicitly,
in Earnest Hooton’s Up from the Ape (2nd ed
...


but not of all intellectual thought
...

“Once evolved, species with their own peculiar adaptations,
behaviors, and genetic systems are remarkably conservative,
often remaining unchanged for several million years
...
”
Some species later in evolutionary time are clearly more
complex in certain ways than many found earlier in time
...
For the most part, the world has not become a strikingly more complex place biologically as a whole
...

Even this brief historical sketch clearly illustrates the
anthropocentric spectacles through which paleoanthro-

KEY QUESTIONS
• Did the intellectual framework provided by the great Chain of
Being lead naturally to the idea of the evolution of species?
• Why did the perception of Man’s place in nature not change much
in some ways between pre- and post-Darwinian eras?
• Why has the notion of progress become such an integral part of
evolutionary thinking within Western philosophy, particularly in
relation to human evolution?
• Does the evolution of qualitatively novel characteristics require
qualitatively novel explanations?

KEY REFERENCES
Cartmill M
...
Int J Primatol 1990;11:173–192
...
The blind watchmaker
...

Eldredge N, Tattersall I
...
New York:
Columbia University Press, 1982
...
Vision with a vengeance
...

———
...
Natural History Nov 1983:20–24
...
Chimp on a chain
...

———
...
Natural History July 1995:6–9, 69–71
...
Chapter 2, Bones of contention
...

Lovejoy AO
...
Cambridge, MA: Harvard
University Press, 1970
...
The meaning of evolution
...

Tattersall I
...

New York: Harcourt Brace and Company, 1998
...
Human ancestors
were seen as overcoming great challenges, and finally triumphing
...
Even today, because the
narrative form is so powerful and seductive, it is hard to avoid
...
” Isaac was referring to the work of
Boston University anthropologist Misia Landau, who has
analyzed the narrative component of professionalanot just
popularaaccounts of human origins
...
“Seldom do they recognize, however, that many scientific theories are essentially
narratives
...

First, in seeking to explain human origins, paleoanthropology is apparently faced with a sequence of events through
time that transformed apes into humans
...
Second,
the subject of that transformation is ourselves
...


SAME STORY, DIFFERENT SEQUENCES
Traditionally, paleoanthropologists have recognized four
key events in human evolution: the origin of terrestriality
(coming to the ground from the trees), bipedality (upright

walking), encephalization (brain expansion in relation to
body size), and culture (or civilization)
...
(See figure 2
...
)
For instance, Henry Fairfield Osborn, director of the
American Museum of Natural History in the early decades of
the twentieth century, considered the order to be that given
above, which, incidentally, coincides closely with Darwin’s
view
...
In other words,
Keith’s ancestral ape began walking on two legs while it was
still a tree dweller; only subsequently did it descend to the
ground
...
2), a contemporary of Keith, encephalization led the way
...
William King Gregory, like his colleague Osborn, argued for terrestriality first, but suggested
that the adoption of culture (tool use) preceded significant
brain expansion
...

Thus, we see these four common elements linked together
in different ways, with each narrative scheme purporting to
tell the story of human origins
...
“If you analyze the way in which Osborn, Keith
and others explained the relation of these four events, you
see clearly a narrative structure,” says Landau, “but they are
more than just stories
...
” In her analysis of paleoanthropological literature, Landau drew upon a system devised in 1925 by the
Russian literary scholar Vladimir Propp
...
Landau reduced the number of stages to nine, but kept
the same overall structure: hero enters; hero is challenged;
hero triumphs
...
3
...
1 Different views of the story: Even though
anthropologists saw the human journey as involving the same
fundamental eventsaterrestriality, bipedalism, encephalization,
and civilizationadifferent authorities sometimes placed these steps
in slightly different orders
...
(Courtesy of Misia
Landau/American Scientist
...
The climate changes,
the forests shrink, and the hero is cast out on the savannah
where he faces new and terrible dangers
...
2 Sir Grafton Elliot Smith: A leading anatomist and
anthropologist in early-twentieth-century England, Elliot Smith
often wrote in florid prose about human evolution
...
4
...
)

overcome them, by developing intelligence, learning to use
tools, and so on, and eventually emerges triumphant, recognizably you and me
...
For instance, Elliot Smith writes about
“
...
” and “
...
” (See figure 2
...
) Roy Chapman Andrews,
Osborn’s colleague at the American Museum, writes of the
pioneer spirit of our hero: “Hurry has always been the tempo
of human evolution
...
Hurry on to the
time when man could conquer the land and the sea and the
air; when he could stand as Lord of all the Earth
...
” Indeed, many of Osborn’s writings
explicitly embodied the notion of drama: “The great drama of
the prehistory of man
...
,” and so on
...
3 The hero-myth
framework: Like folk tales ancient and
modern, accounts of human origins have
often followed the structure of hero myth
...
Recounting
the evolution of any species is, of course,
equivalent to telling a tale of a series of
historical events
...

(Courtesy of Misia Landau
...

Nature has always been reluctant to give up to Man
the secrets of his own early history, or, perhaps
...
4 Adventures in anthropology: Here, a short
passage from Sir Grafton Elliot Smith’s Essays on the Evolution of
Man, published in 1924, illustrates the storytelling tone in which
anthropological writing was often couched
...


HUMANS AS INEVITABLE PRODUCTS OF
EVOLUTION
Of course, it is possible to tell stories with similar gusto about
nonhuman animals, such as the “triumph of the reptiles in
conquering the land” or “the triumph of birds in conquering
the air
...
The fact that the hero of the paleoanthropology tale is Homo sapiensa ourselvesamakes a significant
difference, however
...
Not everyone was as explicit about this as Broom was
(see unit 1), but most authorities betrayed the sentiment in
the hero worship of their prose
...
“The struggle for existence was
severe and evoked all the inventive and resourceful faculties
and encouraged [Dawn Man] to the fashioning and first use
of wooden and then stone weapons for the chase,” wrote
Osborn
...
to develop strength of
limb to make long journeys on foot, strength of lungs for
running, and quick vision and stealth for the chase
...
were
impelled to issue forth from their forests, and seek new
sources of food and new surroundings on hill and plain,
where they could obtain the sustenance they needed
...
”
In the literature of Elliot Smith’s time, the apes were usually viewed as evolutionary failures, left behind in the evolutionary race
...
Instead of evolutionary
failures, the apes came to be viewed as evolutionarily primitive, or relatively unchanged from the common ancestor they

10

Part One: Human Evolution in Perspective

shared with humans
...
Today, anthropologists recognize
that both humans and apes display advanced evolutionary
features, and differ equally (but in separate ways) from their
common ancestor
...
Paleoanthropologists still tend to describe the events in the “transformation of ape into human” as if each event were somehow
a preparation for the next
...
tool-use
enabled brain expansion and the evolution of language
...
” Crudely put, to be sure, but this kind
of reasoning was common in Osborn’s day and persists in
some current narratives
...

“It consists in creating relations between events
...
It is easy to imagine how such an event
might be perceived as a courageous first step on the long
journey to civilization: the defenseless ape faces the unknown predatory hazards of the savannah
...
“It only
acquires such value in relation to our overall conception of
the course of human evolution
...
Such
a scenario would involve continual progress through time,
going in a particular direction
...
This slant, however,
ignores the fact that evolution tends to work in a rather
halting, unpredictable fashion, shifting abruptly from one
“adaptive plateau” to another
...

For instance, one cannot say that the first bipedal ape
would inevitably become a stone-tool maker
...
5 million years (see
unit 23)
...
5 million years
onwards (see unit 21)
...
The
origin of anatomically modern humans after another 2 million or so years was also probably a punctuational event
(see units 27 through 30)
...
As Landau
remarks: “There is a tendency in theories of hominid evolution to define origins in terms of endings
...

All scientists should step back and scrutinize the language
they use, because intertwined within it will be the elements
of many unspoken assumptions
...

Landau’s focus on language in the context of anthropology
made some researchers defensive, because it seems to threaten
the legitimacy of the science
...
The telling of stories had no place in this
construction of how science works
...
” And paleoanthropology is a science of a
special kind, too, partly because it is historical, and therefore
susceptible to storytelling, but mostly because it is meant to
explain how we came to be here
...
”

KEY QUESTIONS
• What is implied by the fact that, although paleoanthropologists in
Osborn’s time employed the same set of events to describe the
transformation of ape to human, those events were linked in many
different combinations?
• Is paleoanthropology particularly susceptible to the invocation of
the hero myth?
• Why do evolutionary scenarios tend to lend themselves to narrative treatment?
• In what context were apes considered to be evolutionary
failures?

2: Human Evolution as Narrative

KEY REFERENCES
Durant J
...
New Universities Quarterly
1981;35:425–438
...
The myths of human evolution
...

Isaac G
...
In: Bendall D
...
Cambridge, UK: Cambridge University Press,
1983:509–543
...
Human evolution as narrative
...


11

———
...
In: Nelson JS, Megill A, McClosky DN
...
Madison: University of Wisconsin Press,
1987:111–124
...
Narratives of human evolution
...

Lewin R
...
Chicago: The University of
Chicago Press, 1997
...
Pluto’s Republic
...


HISTORICAL
VIEWS

3

Two principal themes have been recurrent in paleoanthropology in
the twentieth century
...
Anthropologists have come to recognize a very
close relationship between humans and African apes; and they see
our early ancestors as much less humanlike than was once the case
...
From the time of Darwin,
Huxley, and Haeckel until soon after the turn of the twentieth century, humans’ closest relatives were regarded as being
the African apes, the chimpanzee and gorilla, with the Asian
great ape, the orangutan, being considered to be somewhat
separate
...
Since the 1960s, however,
conventional wisdom has returned to its Darwinian cast
...
1
...
” Darwin plumped for Africa, because that’s where
our closest relatives, the chimpanzee and gorilla, live; Asia
became popular in the early decades of the twentieth century; and Africa has once again emerged as the focus
...
(Hominin is the term now generally used
to describe species in the human family, or clade; until
recently, the term hominid was used, as discussed in unit 8
...
The different views on the origin of modern humans
are, however, imbued with different perspectives of this issue
(see unit 27)
...
1 Shifting patterns: Between the beginning of the
twentieth century and today, ideas about the relationships among
apes and humans have moved full circle
...
2 Hominins as humans: Until quite recently
anthropologists frequently thought about humanlike characteristics
while considering hominin origins, a habit that can be traced back to
Darwin
...


HOMININ ORIGINS IN TERMS OF HUMAN
QUALITIES
Once Darwin’s work firmly established evolution as part of
mainstream nineteenth-century intellectual life, scientists
had to account for human origins in naturalistic rather than
supernatural terms
...
This issue posed a
formidable challengeaand the response to it set the intellectual tone in paleoanthropology for a very long time
...
Once the earliest human forebear became
established upon this evolutionary trajectory, the eventual
emergence of Homo sapiens appeared almost inevitable because of the continued power of natural selection
...
(See figure 3
...
) It was a seductive formula, and one
that persisted until quite recently
...
One notion was that the first step on the road to
humanity was the adoption of upright locomotion
...
(See figure 3
...
) It was into this intellectual climate that the perpetrator of the famous Piltdown
hoaxaa chimera of fragments from a modern human cranium and an orangutan’s jaw, both doctored to make them
look like ancient fossilsamade his play from 1908 to 1913
...
4
...
)
The Piltdown “fossils” appeared to confirm not only that
the brain did indeed lead the way, but also that something
close to the modern sapiens form was extremely ancient in
human history
...
(See
figure 3
...
) One consequence of Piltdown was that Neanderthal
aone of the few genuine fossils of the timeawas disqualified
from direct ancestry to Homo sapiens, because it apparently
came later in time than Piltdown and yet was more primitive
(see unit 27)
...

(See figure 3
...
)
For Osborn, Piltdown represented strong support for his
Dawn Man theory, which stated that mankind originated on
the high plateaux of Central Asia, not in the jungles of Africa
...

Although Osborn was never very clear about what the
earliest human progenitors might have looked like, his ally
Frederic Wood Jones espoused firmer ideas
...
In 1919, he proposed his “tarsioid hypothesis,” which sought human antecedents very low down
in the primate tree, with a creature like the modern tarsier
...


14

Part One: Human Evolution in Perspective
In the early decades of the twentieth century two
opposing views of human origins were current:

Locomotion-first route

Brain-first route

APE

APE

Bipedal ape

Intelligent bipedal ape

Intelligent ape

Bipedal intelligent ape

HUMAN

HUMAN

Figure 3
...


APES BECOME ACCEPTABLE AS ANCESTORS

Figure 3
...
The ready acceptance of the Piltdown
forgeryaa chimera of a modern human cranium and the jaw of an
orangutanaderived from the British establishment’s adherence
to the brain-first route
...
)

During the 1930s and 1940s, the anti-ape arguments of
Osborn and Wood Jones were lost, but Gregory’s position did
not immediately prevail
...
Others, including Adolph Schultz and
D
...
Morton, claimed that although humans probably derived
from apelike stock, the similarities between humans and
modern African apes were the result of convergent evolution
...
This position remained dominant
through the 1960s, firmly supported by Sir Wilfrid Le Gros
Clark, Britain’s most prominent primate anatomist of the
time
...

During the 1950s and 1960s, the growing body of fossil
evidence related to early apes appeared to show that these
creatures were not simply early versions of modern apes, as
had been tacitly assumed
...
At the same time,
those who insisted that the similarities between African apes
and humans reflected a common heritage, not convergent
evolution, were forced to argue for a very recent origin of the
human line
...

Simons, later supported closely by David Pilbeam, proposed
Ramapithecus as the beginning of the hominin line, thus
excluding a human/African ape connection
...
In 1927, G
...
Pilgrim
had suggested that the great apes be treated as a natural
group (that is, evolutionarily closely related), with humans
viewed as more distant
...
Goodman’s molecular
biology data on blood proteins indicated that humans and
the African apes formed a natural group, with the orangutan
more distant (see unit 15)
...
Subsequent molecular biologicalaand
fossilaevidence appeared to confirm Washburn’s original
suggestion that the origin of the human line is quite recent,
close to 5 million years ago
...
(The nomenclature and evolutionary assignment of
Ramapithecus subsequently was modified, too, as described in
unit 16
...
5 Two phylogenetic trees: (a) Henry Fairfield
Osborn’s 1927 view of human evolution shows a very early division
between humans and apes (in today’s geological scale, this division
would be about 30 million years ago)
...
Long
lines link modern species with supposed ancestral stock, a habit that
was to persist until quite recently
...


argument was Sherwood Washburn, of the University of
California, Berkeley
...
The fossil specimen was
Ramapithecus, an apelike creature that lived in Eurasia ap-

THE SINGLE-SPECIES HYPOTHESIS, AND
ITS DEMISE
Meanwhile, discoveries of fossil hominins, and the stone
tools they apparently made, had been accumulating at a
rapid pace from the 1940s through 1970s, first in South
Africa and then in East Africa
...
The most extreme expression of culture’s importance as the hominin characteristic
consisted of the single-species hypothesis, promulgated
during the 1960s principally by C
...

According to this hypothesis, only one species of hominin
existed at any one time; human history was viewed as progressing by steady improvement up a single evolutionary
ladder
...
In this

16

Part One: Human Evolution in Perspective

Figure 3
...
G
...

Front row, left to right: A
...
Underwood,
Arthur Keith (examining the skull), W
...

Pycraft, and Ray Lankester
...
(Courtesy of the American
Museum of Natural History
...
Thus, because all hominins are cultural by definition, only one hominin species could exist at
any one time
...
Subsequent discoveries and analyses implied that several species
of hominin coexisted in Africa some 2 million or so years
ago (see unit 22), suggesting that several different ecological
niches were being successfully exploited
...
Thus, no longer could hominin origins be equated
with human origins (see figure 3
...
(Foley, 2001, and
Tattersall, 2000, provide interestingaand opposingaideas
about why anthropologists embraced this unilinear view of
human evolution
...
Gone is the notion of a scaled-down version of a modern hunter-gatherer way of life
...

Today, hominin origins are completely divorced from any
notion of human origins
...
Questions of hominin origins must now be posed
within the context of primate biology
...
Theories of human evolution
...

Cartmill M
...
Int J Primatol 1990;11:173–192
...
One hundred years of paleoanthropology
...

Fleagle JG, Jungers WL
...
In:
Spencer F, ed
...
New
York: Academic Press, 1982
...
In the shadow of the modern synthesis: alternative perspectives on the last 50 years of paleoanthropology
...

Gee H
...
Nature 1996;381:261–262
...
Chapters 4– 6, Bones of contention
...

Sacket J
...
Evol Anthropol
2000;9:37–49
...
Piltdown: A scientific forgery
...

Tattersall I
...
Evol Anthropol
2000;9:2–16
...
An appraisal of the case against Sir Arthur Keith
...


4

MODERN
EVOLUTIONARY
THEORY

Evolutionary theory is concerned principally with explanations of
species’ adaptation to their environment, the origin of species, and the
origin of trends within groups of related species, such as the increase
in brain size among certain hominins
...
Others see different mechanisms as being important, too
...

Adaptation is pervasive in nature, and in pre-Darwinian
times it was viewed as the product of divine creation
...
In his Origin of Species, published in
November 1859, Darwin explained the purpose of the book
as follows: “I had two distinct objects in view; firstly to show
that species had not been separately created, and secondly,
that natural selection had been the chief agent of change
...

The notion that species do, in fact, change through time
was already in the air in 1859
...
The second goal, showing that natural selection was
an important engine of evolutionary change, remained
elusive until the 1930s, when it became the central pillar
of newly established evolutionary thinking, known as
NeoDarwinism
...
The origin of
species and the pattern of trends among groups of species are
collectively known as macroevolution
...
As stated above, his principal
focus was directed toward change within species, through
natural selection, which was viewed as a slow, steady process
built on minute modifications through time
...
Macroevolution was assumed
to represent the outcome of microevolutionary processes
accumulating over very long periods of time within populations, an assumption that was central to NeoDarwinism as
well
...
Although adaptation through
natural selection remains an important part of modern evolutionary theory, the patterns of change at levels higher than
the individual organism (that is, at the level of species and
groups of species) are now viewed as being more complex
...
Unit 6 will discuss the role
of extinctionsaparticularly mass extinctionsain creating this
pattern
...
First,
members of a species differ from one another, and this
variation is heritable
...
(Although some organisms, most
notably large-bodied species and those that bestow a lot of
parental care, produce few offspring while others may produce thousands or even millions, the same rule applies
...
The principle of natural selection came
to be known (inaccurately) as survival of the fittest, even
though Darwin did not use that term
...
1 Convergent evolution:
The power of natural selection is seen in
its ability to produce similar morphologies
in widely different species
...

Although marsupial and placental mammals
diverged more than 100 million years ago,
their morphologies have become very
similar through similar adaptations as large,
terrestrial carnivores
...


19

Borhyaenid marsupial
(Miocene, Argentina)

Placental wolf
(North America)

Marsupial Tasmanian wolf
(Tasmania, Australia)

Natural selection, then, is differential reproductive
success, with heritable favorable traits bestowing a survival
advantage on those individuals that possess them
...
Such traits will remain favored, however,
only if prevailing conditions remain the same
...

A change in a species’ physical or biological environment
(see unit 5) may alter a population’s adaptive landscape,
perhaps rendering a previously advantageous trait less beneficial or making a less advantageous trait more favorable
...

The power of natural selection can be seen in the
phenomenon of convergent (or parallel) evolution, in
which distantly related species come to resemble one another
very closely by adapting to similar ecological niches
...
(See figure 4
...
) The former is a placental mammal and the latter is a marsupial, making the two species extremely distant genetically, having
been evolutionarily separate for at least 100 million years
...
Anatomical similarities that result from shared
ancestry are examples of homology
...


ESTABLISHMENT OF POPULATION GENETICS
Darwin was well aware that members of a species vary,
and that these variations are heritable: his observations of
natural populations and experiments with domestic breeding
were proof of that ability
...
Although the rules of inheritance
were discovered by the Austrian monk Gregor Mendel in
the early 1860s, the results of his work remained generally
unknown until two decades after Darwin’s death, in 1882
...
He also found that each plant has two genes for
each trait, one from the female parent and one from the
male
...
When the two alleles differ, one form may be dominant and the other recessive (in
humans, for instance, the allele for brown eyes is dominant
relative to the blue allele)
...

Mendel’s experiments were very simple from a genetic
standpoint, with just one or two genes affecting one trait
...
Nevertheless, the
system was amenable to mathematical analysis, and the
selection of favored physical, physiological, or behavioral
traits (the phenotype) could be studied in terms of the
selection of genes that underlay them (the genotype)
...
From time to time, however, the
DNA sequence that represents the information encoded in
a gene becomes changed, often when a “mistake” occurs as
the gene is copied within the germline
...

No simple relationship exists between a mutation and the
degree of phenotypic change it might produce
...
On
the other hand, a similar mutation in a gene that affects
the timing of the program of embryological development
might have dramatic consequences for the mature organism
...
(See figure 4
...
)
The fate of mutations, and therefore their importance in
future evolution, was the topic of intense debate in the early
years of population genetics
...
2 Neoteny in human
evolution: Although the shape of the
cranium in human and chimpanzee fetuses
is very similar, a slowdown in development
through human evolution has produced
adult crania of very different forms, varying
principally in the shape of the face and the
size of the brain case
...


which may be quite common, and the retention, or fixation,
of those mutations in the species’ populations, which is much
less common
...

Until the mid-1940s, evolutionary theory remained distinctly at odds with strict Darwinism, and many different
views were put forth to explain how the pattern of life
was shaped
...
This
theory encompassed three principal tenets
...
Second, this change
results from natural selection, with the differential reproductive success founded on favorable traits, as described
earlier
...
Darwinism had triumphed
...
We will now turn to macroevolution

4: Modern Evolutionary Theory
athat is, the origin of new species and trends among groups
of related species
...
First, an existing
species may be transformed by gradual change through time,
so that the descendant individuals are sufficiently differentiated from their ancestors as to be recognized as a separate
species
...
In this case
there is no increase in the diversity of species
...
This mode is known as cladogenesis,
and comprises a splitting event that yields two species where
previously only one existed
...
(Cladogenesis is also called speciation
...
Adaptive radiation is a characteristic pattern of evolution following the origin of an evolutionary novelty, such as feathered flight (for birds), placental
gestation (for eutherian mammals), or bipedal locomotion
(in hominins)
...
The result, drawn
graphically, is an evolutionary bush, with an increasing
number of coexisting species through time that have all
descended from the same ancestor
...
”
Cladogenesis is most likely to occur when a small, peripheral population of a species is separated from the parental
population
...
When a small population becomes established in one of these ways and then expands, it exhibits
what is termed a founder effect
...
Allopatric speciation
is the most common means by which new vertebrate species
arise
...

So much for the mode of the origin of new species; what
of the tempo and its mechanism? The modern synthesis
argued that macroevolution was simply an extrapolation
of microevolutionary processes: an accumulation of small

21

changes over a long period of time, leading to large resulting
changes
...
(See figure 4
...
)
Because phyletic gradualism is driven by the gradual process of natural selection, it creates new adaptations that,
when sufficiently different from those in the ancestral
species, may lead to a new species that is characterized by
those adaptations
...
Typically, gradual change is not seen
in the record, however
...

Proponents of the modern synthesis adopted Darwin’s
explanation for the absence of transitional forms, which was
that the fossil record is incomplete
...
They argued that, incomplete though
the fossil record may be, it presents an accurate view of the
tempo of evolutionary change
...
Apart from rare
occasions in unusual geological circumstances, the bursts of
change go unrecorded in the fossil record
...
(See figure 4
...
)
An important difference between punctuated equilibrium
and the traditional explanation of species formation relates
to the nature of change that occurs at that time
...


THE ORIGIN OF EVOLUTIONARY TRENDS
Punctuated equilibrium leads to another insight of macroevolution, that of trends within groups of species
...

A second example involves the increase in brain size during
human evolution, at least once the genus Homo had evolved,
some 2-plus million years ago
...
Similarly, the increase in brain size that was

Geological time

22 Part One: Human Evolution in Perspective

Gradualism

Punctuated equilibrium

A measure of species differences

Figure 4
...
Gradualism views evolution as proceeding
by the steady accumulation of small changes over long periods of
time
...
Evolutionary history
reflects the outcome of a combination of these two modes of
change, although considerable debate has arisen as to which mode
is the more important
...
Through the lens of the modern synthesis,
the trends could be explained as progressions that resulted
from directional natural selection
...

If, as noted earlier, species persist unchanged for most of
their duration, then evolution is not directional in this sense
...
Many
factors can influence species’ tendencies for extinction (and
speciation), because the two trends are linked (see units 5
and 6, and figure 4
...

One such factor is the nature of a species’ adaptation
...
The reason is that any change in the
prevailing environment is likely to push specialists beyond
the limits of their tolerances, promoting both speciation
and extinction
...

Suppose, for example, that horse species with large body
size survive longer, for some reason
...
Similarly for hominin species and large brain
size: there is no persuasive evidence to indicate an increase
in encephalization within species; rather, there is a trend
toward larger brain size within the clade as a whole
...

In thinking about the shape of human evolution, an interesting question is this: how many hominin species might
have existed at any one time, and how many in total?
Adaptive radiation leads to a bushy family tree, with multiple
species existing at any point, rather than a linear one, with
just one species existing at any one time
...
The fossil record
of horses has shown, however, that this group was once a
luxuriant evolutionary bush, with multiple species coexisting at any one time
...
As a result of a flurry in the discovery of new hominin
species, the total number of species throughout human

4: Modern Evolutionary Theory
Equus

Recent
Pleistocene

23

Stylohipparion

Hippidion
group

Nannippus
Neohipparion

Pliocene

Pliohippus
One-toed

Calippus
Hipparion
Hipparion

Three-toed

Merychippus

Figure 4
...
In fact, the
evolution of horses is more like a bush
than a directional ladder
...


Hypohippus

Megahippus
Hypohippus
ArcheoAnchitherium
hippus

Miocene
Parahippus
Anchitherium
Miohippus
Oligocene
Mesohippus
Epihippus
Grazing horses
Eocene

history now approaches the theoretical prediction
...


KEY QUESTIONS
• Why are mutations important in evolution, and how do they
become fixed in a population?
• Why is macroevolution not considered to be merely an extrapolation of microevolutionary processes operating over long periods
of time?
• Why is adaptive radiation so common a pattern in evolution?
• What evolutionary factors are most important in shaping the
history of human evolution?

Browsing horses

Orohippus

Palaeotheres, etc
...
Tempo and mode in evolution
...

Foley RA
...
Evol Anthropol
2001;10:5–15
...
Darwinism and the expansion of evolutionary theory
...

Gould SJ, Eldredge N
...
Nature
1993;366:223–227
...
The dynamics of evolution
...

Stebbins GL, Ayala FJ
...
Sci Am July
1985:72–80
...
How does evolution work? Evol Anthropol 1994;3:2–3
...
Paleoanthropology: the last half-century
...

Weiner J
...
New York: Alfred A
...


5

THE PHYSICAL
CONTEXT OF
EVOLUTION

The physical environment, in terms of geography and climate, has
been recognized as being an important driver of evolutionary change
...
Climate change can effect speciation and extinction,
depending on species’ resource needs and tolerances
...
First is
the biotic contextathat is, the interactions between members
of a species and between different species, principally in the
form of competition and resulting natural selection
...

Biologists have long debated the relative contributions of
these two factors in driving evolutionary change
...
He did not
ignore the effects of the physical environment, but saw them
as merely tightening the screws of competition
...
Even in the absence of change in the physical
environment, it was assumed, evolution would continue,
driven by the constant struggle for existence
...
Predators and prey, for instance, were
viewed as being engaged in a constant battle, or evolutionary
arms race
...
The same
evolutionary dynamic would apply to the effect of competition among species for resources
...

This shift in perspective comes from two sources
...
The second source is the
growing understanding that mass extinction is more than
simply an interruption in the flow of life, and instead is a
creative influence in that flow; this idea is discussed in unit 6
...
The physical environment provides two
means by which this process might occur
...
Second, global climate
change may be driven by many factors, including some of the
effects of plate tectonics
...
Continental landmasses, which are less dense than crustal rock,
ride passively atop these plates
...
Continents occasionally
come together, forming larger landmasses; at other times
they separate, producing smaller landmasses
...
(See
figure 5
...
)
For instance, Old World and New World monkeys derive
from a common stock, but followed independent paths of

5: The Physical Context of Evolution

L A U R A S I A

A

A

E

25

G

Equator
G

P A
N

Equator

Tethys Sea

O
N

Permian
225 million years ago

D

W

AN

A L
A

Triassic
200 million years ago

Equator

Equator

Jurassic
135 million years ago

Cretaceous
65 million years ago

Asia

North America

Figure 5
...
Through Earth history, the form
of landmasses has changed constantly,
sometimes with dramatic impact on the
biota living on them
...
Australia’s menagerie of marsupial
mammals evolved in isolation from placental mammals, as
the island continent lost contact with Old World landmasses
more than 60 million years ago
...
Indian
and Asian species migrated into one another’s lands when
the continents united approximately 45 million years ago
...
Africa
and Eurasia exchanged species when the landmasses made
contact approximately 18 million years ago; in the process,
apes joined species making the journey from south to
north and many species of antelope moved in the opposite
direction
...
The isolation of ancestral mammalian
species some 100 million years ago, when landmasses were
particularly fragmented, has recently been suggested to have
prompted the development of the modern mammal orders
...
This theory
posited the origination of modern orders of mammals as a
result of ecological niches having been opened up following
the extinction of the dinosaurs 65 million years ago
...
This fate befell many South American mammals
during the Great American Interchange
...

In addition to influencing evolution by shuffling landmasses, plate tectonics can modify the environment within
individual continents
...
Broadly speaking, 20 million years ago,
the African continent was topographically level and carpeted
west to east with tropical forest; tectonic activity greatly
modified this pattern
...
Beginning 15 million years ago, it produced
localized uplift that yielded tremendous lava-driven highlands that reached 2000 meters and were centered near
Nairobi in Kenya and Addis Ababa in Ethiopia
...
Weakened by
the separating plates, the continental rock then collapsed in
a long, vertical fault, snaking several thousand kilometers
from Mozambique in the south to Ethiopia in the north,
and on to the Red Sea
...
Continuous forest was replaced by a patchwork of
open woodlands and, eventually, grassland savannah
...
More important, the
once topographically even terrain became extremely diverse,
ranging from hot, arid lowland desert to cool, moist highlands, and a range of different types of habitat in between
...
2 Topographic section of
Africa along the equator: During the past
20 million years, tectonic activity beneath
East Africa caused uplift and subsequent
faulting, forming the modern Great Rift
Valley
...
First, it
threw the continent east of the uplifted
highlands into a rain shadow, causing
once-continuous forest cover to shrink
and fragment
...
These effects
are thought to have been influential in the
evolution of the hominins, among other
evolutionary changes
...

Partridge et al
...
For animal species, the kinds of
plant species that are available influence their ability to
occupy any particular biome
...
Overall, however, a topographically diverse terrain will also be biologically diverse
...
For instance, a species that is adapted
to the conditions of high elevation may be prevented from
migrating from one highland to another because the intervening terrain is inhospitable to it
...
The tectonic uplift and vertical faulting that
formed the Great Rift Valley in East Africa produced such
a topography, and may well have created conditions conducive to the evolution of hominins from an apelike ancestor
...
2
...


CLIMATE CHANGE AND HABITAT THEORY
A considerable body of data has been amassed during the
past decade relating to the Earth’s climate during the
Cenozoic, from 65 million years ago to the present, and par-

5: The Physical Context of Evolution
Three “pacemakers” of the Milankovitch climate cycles
(a)
21
...
5 degrees
Earth

Sun

(b)

(c) 0

I

100
Thousands of years ago

Terminations

II

III

IV

200

300

400

V
VI

500

VII

600
Ice volume
glacial cycles

800
900
1000
Summer sunshine
(cal/cm2/day)

Figure 5
...


ticularly for the time period most relevant to human evolution, the last 5 million years
...
Superimposed on this pattern are global cooling
and warming cycles, the so-called Milankovitch cycles, with
periodicities of approximately 100,000, 41,000, and 23,000
years
...
3
...
For example,
prior to 2
...
8 and 1 million years ago, the 41,000-year
cycle prevailed; from 1 million years onward, the dominant
cycle has been 100,000 years
...
The first event, appearing at 5 million
years, involved significant cooling
...
5
and 2
...
The modern Sahara’s roots lie at this point, too
...
5 million
years ago
...
7 million years
ago
...
9 million years ago,
was possibly caused by uplift in western North America and
of the Himalayan range and the Tibetan Plateau
...
The overall pattern
of climate change is therefore extremely complicated, driven
by several different forcing agents
...
The temperature extremes of the Milankovitch cycles
exceed the habitat tolerances of virtually all species, turning
a once suitable habitat into an inhospitable one; the larger
shifts have an even more dramatic impact
...
Thus, it is obvious that most species are able to
survive these repeated climatic fluctuations
...
During global cooling,
dispersal moves toward lower latitudes; during warm periods,
it takes the reverse direction
...

Other biotic responses to climate change are possible as
well, particularly when a threshold of tolerance is exceededa
namely extinction and speciation
...
Although
it has many components, the habitat hypothesis can be
stated simply: species’ responses to climate change represent
the principal engine of evolutionary change
...
Geographical areas
with high topographical variation inevitably have a greater
tendency to create vicariant populations when climate
changes
...
4
...


28

Part One: Human Evolution in Perspective

High
vicariance topography

Low
vicariance topography

Colder

Warmer

Grassland

Woodland

Figure 5
...
(Courtesy of E
...
)

Because of their variable adaptations, different types of
species exhibit different vulnerabilities to climate change
...
Temperate forests and grasslands
become increasingly dominant at higher latitudes
...
In their equatorward migration, grasslands may
be able to occupy an area similar to that in previous climes,
leaving behind patches of vicariant habitat encroached upon
by tundra
...
The reverse
should be true during times of global warming
...
(See figure 5
...
)
Differences are observed among warm-adapted and coldadapted species, of course
...
Anteaters, for instance, are food specialists; because
their food is plentiful in many different ecosystems, however, they can tolerate significant habitat change
...

Species that can survive in different kinds of habitats, or
biomes, are known as eurybiomic; those with narrow
biomic tolerance are deemed stenobiomic
...
All clades
of exclusive grazers and all clades of exclusive browsers consistently show higher speciation and extinction rates than
species that can both graze and browse
...

Habitat theory inevitably places heavy emphasis on physical context as a driver of evolutionary change
...

By now it is clear that the picture is more complex than that:
there is no clear synchrony between climate change and speciation and extinction, although there is a link
...


KEY QUESTIONS
• What kind of fossil evidence would support the Red Queen
hypothesis?
• How could the relative contributions of competition and climate
change to speciation be tested?
• What is the most important component of the physical context of
evolution?
• What changes in the physical environment might have been
important in human evolution?

KEY REFERENCES
Broecker WS, Denton GH
...

Carson HL
...
BioScience
1987;37:715–720
...
Plio-Pleistocene African climate
...

Foley RA
...
J Human Evol 1994;26:275–289
...
In: Bromate T, Schrenk F, eds
...
Oxford:
Oxford University Press, 1999:328–348
...
The influence of global climate change and
regional uplift on large-mammalian evolution in East and Southern Africa
...
, eds
...
New
Haven: Yale University Press, 1995:331–354
...
Humanity’s descent: the consequences of ecological instability
...


5: The Physical Context of Evolution

Epoch
Pleistocene
Pliocene

Million
years ago
0
1
...
5 Climate patterns since the
end-Cretaceous: An overall cooling trend
with local fluctuations marks the Cenozoic
period, which culminates in the Pleistocene
Ice Age
...

(Courtesy of I
...
)

Equable
Warm
Wet
58

Earliest “modern” primates

65

Early primates diversify
Massive extinctions

Paleocene
Cretaceous

———
...
Science 1996;273:922–923
...
The Red Queen
...

Shackleton NJ
...
In: Vrba ES, et al
...
Paleoclimate and evolution
...

Shreeve J
...
Discover July 1996:116–125
...
Habitat theory in relation to the evolution in African

Neogene biota and hominids
...

African biogeography, climate change, and early hominid evolution
...

White TD
...
In: Vrba ES, et al
...

Paleoclimate and evolution
...


6

EXTINCTION
AND PATTERNS
OF EVOLUTION

Mass extinctions have come to be recognized as qualitatively different
from background extinction, which is probably driven by natural
selection
...
Mass extinctions shape
the history of life, principally through the nature of the species that
survive through them
...
Not until half a billion years ago did complex, multicellular organisms evolve,
in an event biologists call the Cambrian explosion
...
The products of this initial,
intensely creative moment in the history of life included all of

the 30 or so animal phyla that exist today
...

In the 530 million years since the Cambrian explosion, 30
billion species have evolved
...
Given that an estimated 30 million
species exist today, it’s clear that 99
...
Some extinctions occur at a
steady, background rate of approximately one species every
four years; others are part of mass extinction events, during
which a great proportion of extant species disappear in a
geologically brief period, measuring from a few hundred to a
few million years
...
1
...
1 Episodic nature of life’s
history: Since the origin of multicellular
organisms in the early Cambrian, life’s
history has documented a steady rise in
diversity, as recorded here by the increase
through time in the number of families
of marine vertebrates and invertebrates
...
(The percentage loss of species
is much higher
...
Typically, the groups that became
dominant after the extinction differed from
those before it
...
)

6: Extinction and Patterns of Evolution

225

Cretaceous

Figure 6
...

(Courtesy of David Jablonski
...
01
1
...
2
23
...
5
55
...
0

Silurian

144
...
5

Mesozoic

Paleozoic

Devonian

439

Epoch

Quaternary

353
...
0

Triassic

290
Carboniferous

Era

Tertiary

Age
(mya)

Cenozoic

Period
Permian

Era

31

225
...

As a result of a burst of research in the 1980s and 1990s
into extinction processes, biologists’ assumptions about mass
extinctionaabout its causes and, more important, its effects
ahave been overturned
...

Now, however, they are recognized as playing a major role in
guiding evolutionary change
...
He also argued
that species become extinct because they prove adaptively
inferior to their competitors
...

The fact of extinction had been demonstrated before
Darwin’s time, by the French anatomist, Baron Georges
Cuvier, in the late eighteenth century
...
The inescapable conclusion was that the
mammoth species no longer existed
...

Cuvier’s observations inspired a great volume of geological
work in the early part of the nineteenth century
...
(See figure 6
...
)
Two particularly devastating catastrophes divided the
history of multicellular life, known as the Phanerozoic, or
visible life, into three eras: the Paleozoic (ancient life), from
530 to 250 million years ago; the Mesozoic (middle life),
from 250 to 65 million years ago; and the Cenozoic (modern
life), from 65 million years ago to the present
...
This world view was known as
Catastrophism
...
In his Principles of
Geology, published in three volumes in the 1830s, Lyell
argued that the geological processes we observe todayasuch
as erosion by wind and rain, earthquakes and volcanoes, and
so onaare responsible for all geological changes that have
occurred throughout Earth history
...

Lyell’s scheme came to be known as Uniformitarianism
...
Uniformitarianism won decisively, and Catastrophism

32 Part One: Human Evolution in Perspective
was banished from the intellectual arena as a relic of earlier
thinking
...
Earth history evidently is not one of gradualistic progression, as Lyell and Darwin averred, but instead
a litany of sporadic and spasmodic convulsions
...

This last groupaknown as the Big Fiveacomprises biotic
crises in which at least 75 percent of species became extinct
in a brief geological instant
...
This handful of major events, from oldest
to most recent, include the following: the end-Ordovician
(440 million years ago), the Late Devonian (365 million years
ago), the end-Permian (250 million years ago), the endTriassic (210 million years ago), and the end-Cretaceous
(65 million years ago)
...
Traditionally, these
putative sources include a drastic fall in sea levels (sea-level
regression), global cooling, predation, and interspecies competition
...
In the past
two decades, however, two other agents of extinction have
been suggested: asteroid impact and massive lava flow
...

In 1979 Luis Alvarez, a physicist at the University of
California, Berkeley, and several colleagues suggested that
the end-Cretaceous extinction, which marked the end of the
dinosaurs’ reign, was the outcome of Earth’s collision with a
giant asteroid
...
Iridium is rare in crustal and continental
rock, but common in asteroids
...
The ensuing
catastrophic results affected plant life first and then the
animals that depend on it
...
In the
years since its proposal, a large body of evidence has been
gathered in its support, including evidence of an impact
crater at the pertinent time, 65 million years ago
...
3
...
Such impacts might not be the
sole cause of extinction, however; the meteors might have
struck a biota that was already fragile for other reasons,
including those mentioned earlier, or they might have
weakened the biota, making it vulnerable to secondary mechanisms of extinction
...

Within 5 to 10 million years of the event, the diversity equals
and often exceeds pre-extinction levels
...
Typically, the groups of species that come to
dominate the marine and terrestrial ecosystems differ from
those that dominated prior to the collapse
...
Mammals had
coexisted with dinosaurs for more than 100 million years,
but they were small and probably few in number
...

This concept raises questions about what makes some
groups of species vulnerable to extinction, or partial extinction, while others fare better
...
But what about the
bursts of higher rates of extinction? Is mass extinction merely
background extinction writ large? Do marine regressions
(see figure 6
...
”
Counterintuitively, random processes can produce patterns
...
In computer simulations of species communities over long periods
of time, in which speciation and extinction were allowed to
happen randomly with no external force operating, they

6: Extinction and Patterns of Evolution

33

Tropic of Cancer
Mimbral
Impact site
Progreso

Gulf of Mexico

Mexico City

Belize

Mexico

Guatemala

Honduras

Pacific Ocean

Nicaragua

Figure 6
...
Since then, much evidence has
been amassed in support of the proposal,
including the recent discovery of a huge
impact crater in the Yucatan Peninsula,
dated at 65 million years
...
In other words, species numbers
fluctuated significantly with no external driving force, but
only rarely crashed in a way that could be termed a mass
extinction
...
This research also
partly inspired the realization that bad genes could not provide the sole explanation of the pattern of life
...


MASS EXTINCTIONS ARE QUALITATIVELY
DIFFERENT
The University of Chicago paleontologist David Jablonski
has investigated the nature of that selection by comparing
the pattern in background and mass extinction periods
...
Species that are
geographically widespread resist extinction, for instance
...
S
...
A group of related species, a clade, resists extinction
if it contains many species rather than only a few
...

When Jablonski examined the fate of mollusc species and
species’ clades across the end-Cretaceous extinction, he saw
a very different picture
...
The
only rule he could discern was valid for groups of related
species, or clades
...
If a group of species occurred over a wide
geographic range, then they fared better in the biotic crisis
than those that were geographically restricted, no matter
how many species made up the clade
...
are far less
important than membership in the particular communities,
provinces, or distributional categories that suffer minimal
disturbance during mass extinction events,” wrote Jablonski
...
And it certainly cannot anticipate rare events
...
Consequently,
most species never experience such bursts
...
Species cannot adapt to conditions they do not
experience
...

Mass extinctions, then, restructure the biosphere, with an
unpredictable set of survivors finding themselves in a world
of greatly reduced biological diversity
...

This time provides an evolutionary opportunity offered to a
lucky few
...
We are but one of millions of species here on Earth, the
product of half a billion years of life’s flow, lucky survivors
of at least 20 biotic crises, including the catastrophic Big Five
...
Its survival, and our subsequent
existence, was largely a matter of factors having nothing to
do with adaptive qualities
...
4 Sea-level changes: Sea-level regression is a probable
factor in some extinctions, and is associated with many of them
...


and mass extinction
...

This idea makes sense because, in the history of life, many
successful species or groups of species have met abrupt
ends in mass extinctions
...

Some authorities argue that the diversity of dinosaur species
was already in decline when they vanished completely at
the end-Cretaceous extinction
...

Natural selection operates cogently at the level of the individual, in relation to local conditions, reflecting the impact
of competitors and prevailing physical conditions
...
An extraterrestrial impact
...

Courtillot VE
...
Sci Am Oct 1990:85–92
...
Lessons from the past: biotic recoveries from mass extinctions
...

Gould SJ
...
Natural History Oct 1994:6–12
...
Biotic recovery from mass extinction
...

Hsü KJ
...
Catastrophism in the extinction
debate
...
The mass extinction debates
...

Jablonski D
...
In:
Kaufman L, Mallory K, eds
...
Cambridge,
MA: The MIT Press, 1993:47–68
...
Survival without recovery after mass extinctions
...

McLaren DJ
...
The mass extinction debates
...

Raup DM
...


35

———
...
In: Fitch WM, Ayala FJ,
eds
...
Washington, DC: National
Academy Press, 1995:109–124
...
Flood basalts: bigger and badder
...

Van Valen LM
...

In: Glen W, ed
...
Palo Alto: Stanford
University Press, 1994:200–217
...
Typically, the techniques
depend on determining the age of material associated with the relics
in question, such as the strata in which they are found or other fossils
of known age
...


An accurate time scale is a crucial aspect of reconstructing the
pattern of evolution of the anatomical and behavioral characteristics of early hominins
...
Paleoanthropologists’ focus is on
the last 10 million years or so, which includes some of those
gaps
...

Direct methods apply the dating techniques to the objects
...

First, for most objects of interest, no methods are as yet available for direct dating
...
Some methods,
such as carbon-14 dating and electron spin resonance,
may be applied directly to teeth or young fossils, and indeed
to the pigments of rock shelter and cave paintings; in addition, thermoluminescence dating may be applied directly
to ancient pots, flint, and sand grains
...

In practice, indirect dating methods represent the typical
approach
...
This strategy
may involve direct dating on nonhuman fossil teeth that
occur in the same stratigraphic layer, by electron spin resonance, for instance, or by thermoluminescence dating of flints
associated with human fossils
...
Fossils or artifacts may be

attributed an age through information about the evolutionary stage of nonhuman fossils associated with them, a technique known as faunal correlation
...
Stratigraphic layers accumulate from the bottom
up, so that the lower layers are oldest and the upper layers
youngest
...

This unit will survey briefly the principal techniques
available and identify where they are best applicable
...

Relative dating techniques give information about the site
in question by referring to what is known at other sites or
other sources of information
...


RELATIVE DATING TECHNIQUES
Relative dating techniques include faunal correlation and
paleomagnetism
...
For instance, the geological time scale for the history of life on Earth is built upon
major changes in fossil populations, such as appearances and
disappearances of groups
...
Among the most
important species for paleoanthropologists are elephants,
pigs, and horses
...
If
a hominin fossil is found in sedimentary layers which also
include fossil pigs that are known to have lived, for instance,
between 2 million and 1
...
(See figure 7
...
)

40

Part Two: Background to Human Evolution
Volcanic rocks

1
...
1 million
years ago

Potassium-argon
ages of reversals
(mya)
0
...
03

0
...
69
1
...
0 million years ago

1
...
0
Tuff 2,
forming
Tuff 1

Field
polarity

2
...
89
0
...
61
1
...
64
1
...
95
1
...
11
2
...
43
2
...
0

Present
Tuff 2, forming

3
...
01
3
...
15
3
...
80
3
...
0

4
...
20

Normal
Reversed

4
...
1 The life and date of a fossil: Fossils cannot be dated
directly
...


The principle behind paleomagnetism is based on the
fact that the Earth’s magnetic axis reverses periodically
...
During
reversals, which occur every few hundred thousand or million years, a magnetic needle would point south
...
Geologists have accumulated much information about
past polarities and have constructed a chart showing the
dates of reversals
...
By itself this information is insufficient
to date a site, because the knowledge that a particular layer

Figure 7
...
The stripe pattern seen here
represents the main reversals, and reference to it can help date sites
...
A
series of layers that reveal a relatively large section of the
overall pattern is sometimes sufficient to provide a more
secure date
...
2
...


ABSOLUTE DATING TECHNIQUES:
RADIOPOTASSIUM DATING
The majority of absolute dating methods are radiometric,
which depends on radioactive change in certain minerals
...
First, some action

7: Dating Methods

41

Volcanic
eruption

Figure 7
...
A small
percentage of the potassium exists as a
radioisotope, potassium-40, which has
argon-40 as one of its decay products
...
The
crystals can then be individually heated by
laser beam, and the emitted argon-39 and
argon-40 measured separately in a gas
chromatograph
...


sets a radiometric “clock” to zero, such as the heating that
rock experiences during volcanic eruption or burial in the
Earth
...

The most important radiometric technique that has been
applied in paleoanthropology is radiopotassium (potassium/argon) dating
...
01 percent of all naturally occurring potassium,
slowly decays to argon-40, an inert gas
...
The high temperature experienced
during eruption drives out the argon (and other gases) from
the mineral, and the clock is set to zeroathe time of the eruption
...
The age calculation is based on measurements of the potassium concentration and the accumulated argon-40 in potassium-rich
minerals, such as feldspar
...
Even a few crystals of, for
example, Cambrian-age rock in a gram of 2-million-year-old
ash can produce an erroneously old date
...
In 1959, Mary Leakey
found the famous Zinjanthropus fossil (see unit 19), the first
early hominin discovered in East Africa, at this site
...
75 million years, was double the
age inferred by indirect means
...

Since that time two important advances have taken place
with radiopotassium-based dating
...
The rock is initially irradiated with neutrons, which transforms the stable
potassium-39 into argon-39; when the rock is then heated,
the two argon isotopes, 39 and 40, are released together and
can be measured simultaneously on a gas chromatograph
...
This technique is known as argon-39/argon-40
dating
...
3
...
The advantages of the new
technique, known as single-crystal laser fusion, are several,
including avoiding the problem of contamination
...
5 million years
old
...
There is no effective upper limit of age
estimation
...
Naturally occurring glass often contains the isotope
uranium-238, which decays through powerful fission
...
Once again, the clock is set
to zero during volcanic eruption, which expunges existing
tracks
...

The preparation of glass for the technique is tedious, however, and the counting of tracks not always reliable
...

Radiocarbon dating is the best known of all radiometric
techniques, but because of its short time depth has limited
applications in paleoanthropology
...
Some
small percentage consists of carbon-14, a radioactive isotope
that decays relatively rapidly
...
The same ratio applies
for animal tissues, which effectively are built from plant
tissues
...

As time passes, the ratio of carbon-14 to carbon-12 becomes
increasingly smaller, a decline that forms the basis of the
clock
...

In principle, any organic material can be dated by the
carbon-14 technique; in practice, many tissues decay too
quickly to use this approach
...
In Australia, rock paintings have recently been dated
from blood that formed part of the pigment
...

With the recent application of accelerator mass spectrometry
to increase the sensitivity of measuring carbon-14, the useful
range of the technique can be from a few hundred years to
perhaps 60,000 years or a little more
...
In

addition, amino acid racemization has been used to date
materials
...
Neither the uranium series
technique nor amino acid racemization is as powerful or as
applicable to paleoanthropology as the other absolute dating
techniques
...
The radioactive rays knock off
the negatively charged electrons from atoms, leaving positively charged “holes
...
But all minerals contain impurities, such as lattice defects and atoms that can “trap” roving
electrons, keeping them at an intermediate energy level
...
The
number of trapped electrons in a newly unearthed mineral
therefore provides a measure of the time that has passed
since the mineral was last exposed to heat
...

In the thermoluminescence technique, the artifacts are
heated under controlled conditions to release the electrons
...

Electron spin resonance detects the trapped electrons in situ,
where they act as minute magnets that become oriented
when exposed to a strong magnetic field
...
The strength of the signal provides a measure of the
number of trapped electrons
...
(See figure 7
...
)
In principle, both thermoluminescence and electron
spin resonance techniques can reveal dates between a few
thousand and 1 million years ago
...


7: Dating Methods

43

1 Products of radioactive decay interact with
nearby atoms, boosting energy levels
...

Gamma ray
n1
–

Trap

n0
Trapped electrons are detected
directly by electron spin resonance
...

n1
–

Trap
–

Light
proton

n0

Figure 7
...
The two techniques measure
these trapped electrons by different means
...
The intensity of this light provides a measure of the number
of trapped electrons
...
(See text for details
...
5 Range of dating methods:
The full range of dating methods available
to paleoanthropologists begins at a few
hundred years and extends to many
millions of years
...
5 million years
...
5)
...
The cave sites in South
Africa are examples of a too-complicated stratigraphy
...
Luminescence dating relevant to human
origins
...

Brown FH, et al
...
In: Delson E, ed
...

New York: Alan R Liss, 1985:82–90
...
The edge of time: dating young volcanic ash layers with
the argon-40/argon-39 laser probe
...

Deino A, et al
...
Evol Anthropol 1998;6:63–75
...
Luminescence dating and modern human origins
...

Grün R
...
Evol
Anthropol 1993; 2:172–181
...
Rock of agesacleft by laser
...

Ludwig KR, Renne PR
...
Evol Anthropol 2000;9:101–110
...
Uranium series dating in paleoanthropology
...

York D
...
Sci Am Jan 1993:90–96
...
There are three major methodologies, each of which emphasizes a different aspect of a lineage’s history,
such as anatomical similarities and strict phylogeny
...

Increasingly, however, molecular evidence, especially DNA, has been
used
...


Systematics is the study of the diversity of life and the
relationships among taxa at all levels in the hierarchy of
life, from species to genus to family to order, and so on up to
kingdom
...
Conventionally, taxa above
the level of genus are referred to as higher taxa
...
Traditionally,

Kingdom

classification has been based on anatomical characters
...
The advantages and
disadvantages of both approaches will be discussed
...
1 for the grey wolf, Canis lupus
...
Genera are
grouped into families; here, the wolf and the jackal are in the
same family as foxes (genus Vulpes), with the family name
Canidae
...
The class
Mammalia joins with other vertebrate classes (such as
Carnivora and Insectivora) to form the phylum Chordata,
which is one of approximately 30 animal phyla that constitute the kingdom Animalia
...
Different species may
share the same specific name but are linked to different

Animalia

Phylum

Chordata
Vertebrata

Subphylum
Class

Mammalia
Carnivora

Order

Family

Figure 8
...

Developed in the mid-eighteenth century,
the system is still used today
...
lupus

Part Two: Background to Human Evolution

46

genus names, such as Proconsul africanus (a fossil ape; see
unit 16) and Australopithecus africanus (an early hominin; see
unit 20)
...


Phenetics

Evolutionary taxonomy

Cladistics

PHILOSOPHIES OF CLASSIfiCATION AND
SYSTEMATICS

1

2

3

4

Focuses solely on
relatedness

If evolution proceeded at regular rates, so that after
branching two lineages diverged steadily in terms of morphological adaptations, then the phenetic pattern would be
identical to the phylogenetic pattern
...
Sometimes a new lineage will diverge
quickly, accumulating many evolutionary novelties that put
a great morphological distance between it and its sister
species; sometimes a new lineage will remain almost identical to its sister species over vast periods of time, with the
morphological distance remaining minimal while genetic
distance increases
...

The choice of a classification system therefore becomes a
matter of philosophy: Should the grouping be developed
according to overall morphological similarity, which emphasizes adaptation? Or should it reflect relatedness? Which is

(c) Classification
5

6

7
Order

Species 1–7

Suborder

Species 4–7

Family
(b) Cladistic relations

Combines adaptation
and relatedness

Figure 8
...
For instance, by concentrating on
characteristics that reflect genetic relatedness, cladistics produces
an evolutionary tree
...
Evolutionary taxonomy steers a middle path between
the two
...

After 1859 and the publication of Darwin’s Origin of Species,
however, biologists could approach classification with evolution explicitly in mind
...
Recent years have
witnessed surprisingly heated debate over precisely how
classification should be performed
...

Currently three major schools of classification address the
hierarchies of living things: phenetics (also called numerical
taxonomy), which emphasizes overall anatomical similarity,
and is therefore rooted in adaptation and does not necessarily reflect phylogeny; cladistics (also called phylogenetic
systematics), which emphasizes only phylogeny; and evolutionary systematics, which is somewhat intermediate
between the other two approaches in its philosophy
...
2 and 8
...
)

(a) Phylogeny

Emphasizes
adaptation

Species 5–7

Genus

Species 5–6

1
2
3
4
5
6
7

Species

Species 5

Figure 8
...
(b) A cladistic
classification
...


8: Systematics: Morphological and Molecular

Figure 8
...
By contrast, the wing of a bird
and the wing of a butterfly, although they
perform the same task, are not derived from
the same structures: they are examples of
analogy
...
Cladists argue that the phylogenetic hierarchy is the
only important reality, whether we discover it or not
...
The challenge is being able to
infer that pattern from the morphology and other evidence,
such as genetics
...
Phenetics compares
as wide a range of characters as possible between a group
of species to produce multivariate cluster statistics, which is
effectively an average of all such comparisons
...
In fact, practitioners frequently must choose among several possible
patterns, betraying the fact that the method is less objective
than is often claimed
...
Although many characters that are
shared among species are the result of common descenta
that is, homologyasome will reflect convergent, or parallel,
evolutionathat is, analogy
...
4 and 8
...
) Only
homologous characters can be used to reconstruct phylogenies, because they are what link evolutionarily related species
together (see unit 4)
...
This
latter attribute is called character state
...
In any group
of species under comparison, some homologous characters
will be considered primitive and some derived; it is the
derived characters that uniquely link species
...
For instance, baboons, chimpanzees,
and humans all have nails on the ends of their fingers
...
Fingernails are a characteristic feature
of all primates
...
Some dozen or so characters are
found uniquely among baboons, chimpanzees, and humans
that are absent from New World monkeys and prosimians;
these attributes represent shared derived characters for
the Catarrhini (the infraorder that encompasses the Old
World monkeys, apes, and humans as a group) with respect
to primates
...
For instance, although the
possession of fingernails is a primitive character within the
Catarrhini with respect to other primates, it is a derived character for primates as a whole: it distinguishes them from
other mammals
...
Deciding whether a character
state is primitive or derived in a particular species comparison
is known as deciding its polarity
...
This idea, simply stated, is the principle behind
cladistics
...
Cladists reject paraphyletic
groups and polyphyletic groups as unnatural groups
...
If, for instance, only some descendants of
the common ancestor diverged significantly away from the
original adaptation, the phenetic approach would recognize

No use for
systematics

Figure 8
...

Homologous characters come in two forms:
primitive and derived
...
Derived
characters are the key to relationships
because they occur in only some of the
species under study and therefore can be
used to differentiate within the group
...
Polyphyletic groups arise
when members of different lineages converge on a similar
adaptation; pheneticists would recognize these species as a
natural group
...
(See figure 8
...
)

CLADISTIC PRACTICE AND HOMININ
CLASSIfiCATION
The cladistic approach was originally developed by the
German systematist Willi Hennig in 1950, and in recent years
it has become the approach of choice for many researchers
in paleoanthropology
...
For instance,
shared derived characters are synapomorphies
...
A derived character not shared with other species is an autapomorphy
...

Determining relationships between species involves two
steps
...
Second, polarities of homologous character
states must be selected: are they primitive (plesiomorphic) or
derived (apomorphic)? How is polarity determined?
Suppose, for example, one is assessing the bony ridge
above the eyes, which is found in chimpanzees, gorillas, and
the human lineage, but not in orangutans
...
6 Different types of groups: In (a), the evolution of
shared derived characters leads to the formation of a monophyletic
group
...
Convergent evolution may yield species with similar

adaptations; these species may be encompassed within a
polyphyletic group
...

Pheneticists accept the reality of both paraphyletic and polyphyletic
groups because they reflect the results of evolution, or adaptation
...
This process
is known as an outgroup comparison
...
The brow ridge happens to be absent in Old World
monkeys, which implies that indeed it is a synapomorphy
for the African apes and humans
...
(See figure 8
...
)
No one, however, likes to base such a judgment on a single
character
...

The importance of multicharacter comparison becomes evident as the researcher often finds that one subset of characters might imply one pattern of relationship while a second
subset points to another
...
The conclusion from this apparent confusion is
that anatomical characters are often extremely difficult to
assess and interpret
...
A
second analysis showed humans and orangutans as a clade,
with chimpanzees and gorillas as a second clade
...

Now, suppose that this last-mentioned phylogenetic pattern is correctaand molecular data support this classification
(see unit 15)
...
Traditionally, humans and their
direct ancestors have been assigned to the family Hominidae, while the African apes and the orangutan occupy a
separate family, the Pongidae
...

If phylogeny is to be accurately reflected in classification,
then one possibility is as follows
...
Humans would be the sole occupant
of the subfamily Homininaeahence the more general term
“hominin” rather than the previously used “hominid
...

Accurate in cladistic terms though this grouping may be,
pheneticists and evolutionary taxonomists would demur
...
According to this argument,
maintaining family status for the apes but separate family
status for humans is therefore appropriate
...
Various kinds of data are relevant here, including DNA sequences, comparison of immunological reactions
of proteins, comparison of electrical properties of proteins
(gel electrophoresis), and DNA–DNA hybridization, which
effectively compares the entire genetic complement of one
species with that of another
...
7 Relative status of
characters: The state of a character
depends on the reference point
...
Thus, fingernails would not
serve to distinguish apes from, for example,
monkeys
...

Thus, fingernails serve to distinguish
primates from other mammals
...
This character distinguishes apes
from monkeys
...


exception of DNA sequence data, provide a measure of
genetic distance between the species being compared,
which is equivalent to the phenetic measure of overall similarity
...

Only those techniques that produce information about DNA
sequence are accessible to cladistic analysis, because the
sequence data are equivalent to characters whose state can
be determined directly (that is, the presence or absence of
particular nucleotides)
...
Scrutiny of similarities
and differences among species’ DNA therefore permits their
evolutionary relationships to be inferred
...

First, because molecular data are derived from the genes of
a species, they were envisioned as carrying the fundamental
record of evolutionary change
...
Natural selection produces convergence, through adaptation to similar environmental conditions
...


8: Systematics: Morphological and Molecular
Species A
Gene
X

Time scale (millions of years ago)

Convergence toward similar mutations in different lineages
is therefore highly unlikely, except by chance
...

Moreover, because genetic difference between lineages
was suspected to proceed in a regular manner, the notion of a
molecular evolutionary clock was developed
...
Last, morphological features express
complex and mostly unknown sets of genes and regulatory
interactions among genes
...
According
to proponents of molecular systematics, simplicity yields
reliability
...
For instance, it is
now recognized that the dynamics of mutation are highly
complex, including the fact that not all regions of a gene or
other regions of DNA are equally susceptible to change;
indeed, some regions are highly susceptible to similar kinds
of change
...
Moreover, some mutation events may
become hidden through “multiple hits
...
As time passes, other mutations will accumulate as well
...
If a later mutation
occurs at a previously mutated site, however, then the count
will be too low, giving an erroneous conclusion
...
Statistical methods are being
developed to try to accommodate this factor
...
The issue here relates to the potential
difference between the species tree and the gene tree
...
If all genes in two
daughter species begin to diverge only when the populations diverged, then the gene tree would be the same as the
species tree
...

Genes often develop variants (polymorphisms) within a
population, so that some individuals may possess one variant

Present

X

X1

Species B

Limitations of molecular systematics

51

Species C

Figure 8
...
A
speciation event occurs later, producing species B and C
...
A comparison of the
differences between X and X1 would overestimate the time at which
the daughter species B and C diverged
...


while other individuals carry the other
...

Suppose a polymorphism of a gene X arose in a species A
some 4 million years ago, giving variant X in some individuals and variant X1 in others
...
Such a situation
can lead to speciation (see unit 4)
...
Calculations
based on the nucleotide differences between X and X1 would
indicate that the two daughter species diverged 4 million
years ago, when their separate sequences would have begun
to diverge (this is the gene tree)
...
In general, therefore, when the gene tree/species
tree problem arises, the divergence date inferred from the
molecular data will be too old
...
8
...
It was once assumed that mutations
accumulated at a regular rate in all genes, in all lineages, and

52 Part Two: Background to Human Evolution
B

C

Genetic divergence

A

2

Stochastic clock
Metronomic clock

1

Figure 8
...
At 1, a split occurred, leading to species C and
a second lineage
...
According to the rate test, if the average rate
of genetic divergence is the same in all lineages, then the genetic
distance from species A to species C (dotted line) should be the same
as the genetic distance from species B to species C (dashed line)
...


at all times in lineages’ histories
...
In fact, a series of clocks would operate, each ticking regularly but at different rates
...
It has now been established that some genes in
some lineages at some points in their evolutionary history do
indeed accumulate mutations in a clocklike manner
...
The notion of
a global clock is therefore no longer tenable
...
Researchers must determine whether their gene of
interest is behaving in a clocklike manner, using the relative
rate test (see figures 8
...
10), before they can proceed to
measure branch lengths in phylogenies
...
An important feature of evolution
is adaptive radiation, which occurs when a new group diversifies at its establishment, yielding many lineages with
unique features that subsequently may change little
...
10 The molecular clock: If genetic mutation were
to occur at a constant rate, then biologists would have access to a
completely reliable, “metronomic” molecular clock
...
By bringing
together data on genetic divergence from different regions of DNA,
it is possible in principle to average out these fluctuations, thereby
providing a good, average clock
...


accumulation of genetic mutations would be unable to track
the details of the brief burst of change, for the following
reasons
...
DNA sequences that change
rapidly, on the other hand, would capture such change,
but this information would be overwritten to the point of
illegibility by subsequent mutation
...

The rapid radiation of placental mammals near the endCretaceous extinction, 100 million years ago, is a good
example of this type of development
...
Morphological
characters necessarily represent only a subset of this information
...
Morphological

8: Systematics: Morphological and Molecular

53

2

...


2


...


3


...


4


...


5


...


C
T

C

T
Tree 1
(1 step)

T
T

2

T

4

3

5

1

2

4

3

5

1

C

T

T

C

T

C

T

T

C

T

C

T

T

C

T

T

C

T

T

T

Tree 2
(2 steps)

C
T

T

Tree 3
(3 steps)

C
T

C

T

Figure 8
...
By
concentrating on position 3 in this instance, the parsimony
technique seeks to find the tree with the lowest number of

mutational steps to link all population members
...
The parsimony technique would select tree 1 as the
most likely relationship among the five individuals
...
It is also powerless to discern evolutionary history in
cases involving limited morphology, such as in the early
divergence of microorganisms nearly 3 billion years ago
...
Its application to the issue of the origin
of the hominin clade has already been mentioned (see also
unit 15)
...


trees are possibleaor some 10,000 times as many trees as
there are atoms in the universe
...
9 × 1054 years to
complete the jobathat is, 2 × 1045 times the age of the Earth
...
In reality, many trees
are produced, each with equal or nearly equal probability
of being correct
...

Methods employing the parsimony principle are currently the most popular and powerful for phylogenetic analysis
...
(See figure 8
...
) Evolutionary change is
inherently of low probability, so simple paths going from
character state A to character state B are themselves inherently likely to be simple rather than complex (involving,
for example, reversals of evolutionary direction)
...
(See
figure 8
...
)

Methods of phylogenetic analysis
The raw data, whether molecular or morphological, are just
the starting point for phylogenetic reconstruction
...

Whatever the method, the task is formidable
...
With a mere 50 species, for example, 2
...
12 Two views of hominoid
(humans and apes) classification:
Classification (a), the traditional scheme,
emphasizes adaptation, putting the African
and Asian great apes in one family, the
Pongidae, with humans being the sole
occupant of the family Hominidae
...
Classification (b)
is based on a phylogenetic perspective,
particularly on genetic evidence, and groups
humans and the African apes in the family
Hominidae
...
Strict adherence to the
most recent genetic evidence would alter
the classification further (see unit 15)
...
Rates of DNA sequence evolution differ between taxonomic groups
...

Hillis DM, et al
...

Science 1994;264:671– 677
...
Molecular evolutionary clock and the neutral theory
...

King MC, Wilson AC
...
Science 1975;188:107–116
...
Patterns in evolution: a molecular view
...
H
...

Marks J
...

Molecular evolutionary clock
...

Patterson C, ed
...
Cambridge, UK: Cambridge University Press, 1987
...
Congruence between molecular and morphological phylogenies
...

Stewart CB
...
Nature
1993;361:603–607
...
The study of the myriad processes that take
place between an animal’s death and its bones becoming fossilized is
called taphonomy
...


The fossil and archeological records serve as the principal
sources of evidence upon which human prehistory is reconstructed
...
In recent years, a tremendous emphasis has
been placed on understanding the multifarious processes
that impinge on bones and stone artifacts that become part of
the record
...

Death is a bewildering, dynamic process in the wild
...
Once the primary predator has eaten its fill, scavengers, which in modern
Africa would include hyenas, jackals, vultures, and the like,
move in
...

The remaining bones dry rapidly under the sun
...
Passing
herds of grazing animals bring a new phase of disarticulation
and disintegration as hundreds of hooves kick and crush the
increasingly fragile bones
...
Some of the skeleton may indeed
be miles away, lying among the cache of bones in a hyena’s
den
...
Others will have been compressed
into the ground by the pressure of passing hooves, often
being splintered in the process
...

Given that such a fate awaits most animals in the wild, it
is perhaps unsurprising that the fanfared announcements
of ancient hominin discoveries typically mean an interesting tooth, jaw, arm bone, or, rarely, a complete cranium
...
Dated at approximately 1
...
The individual, who was about
nine years old when he died, came to rest in the shallows of a
small lagoon
...


Dynamics of burial
To become fossilized, a bone must first be buried, preferably
in fine alkaline deposits and preferably soon after death
...

The chemical process that turns bone into stone is known as
diagenesis
...

As it happens, the forces that can bury a boneafor example,
layers of silt from a gently flooding riveracan later unearth it
as the river “migrates” back and forth across the floodplain
through many thousands of years
...
Light
bones will be transported some distance by the river, perhaps
to be dumped where flow is slowed, while heavier bones are
shifted only short distances
...
Behrensmeyer, a lead-

9: Science of Burial

Death
Living
organism

Immediate
burial

Diagenesis
Buried
remains

Corpse

Delayed
burial

57

Fossil
record

Delayed
burial

Exposed
remains

Figure 9
...

If a corpse lies on the ground surface for any length of time,
many processes can cause damage, to different degrees, often
disarticulating the skeleton and scattering the pieces
...


ing taphonomist at the Smithsonian Institution (Washington,
DC), identifies transport and sorting by moving water as one
of the most important taphonomic influences
...
For hominin remains, this activity often results in accumulation of hundreds of teeth and
little else, as the researchers working along the lower Omo
River in Ethiopia know only too well
...
1
...
At one time, hominins were thought to live in
these caves, and the bones of other animals found with them
were suspected to represent remains of food brought there to
be consumed in safety
...
In many ways, the South African caves present
one of the most severe taphonomic problems possible, but
with years of patience a group of workers (in particular, C
...

Brain) has cut through the first impressions and progressed a
little closer to the truth
...
The profile of skeletal parts present
matches what would be expected after carnivores had eaten
the softer parts
...
Exactly how much time is represented in these
fascinating accumulations, and when they occurred, is difficult to determine
...

One area of investigation in which taphonomic analysis
has been particularly crucial in recent years is in the study
of ancient assemblies of bones and stonesain other words,
putative living sites
...
These
concentrations of broken bones and chipped stones have
long been assumed to be the product of hunting and gathering
activity such as that seen among surviving foraging peoples
...

In some cases, however, careful taphonomic analysis of
the geological setting and the composition of the bone and
stone assembly has shown such “sites” to result from water
flow, with the material having been dumped by a stream in
an area of low energyain other words, the assembly is not
an archeological site, but a hydrological jumble
...
For example, did early hominins use the stones
to butcher carcasses?
Taphonomists have determined the stages through which
bones go as they lie exposed to the elementsathis process,
known as weathering, can be calibrated
...
Applying this technique to the sites at
Olduvai reveals that in many cases bones accumulated over
periods of 5 to 10 years, which would be unheard of in modern hunter-gatherer sites, which are occupied only briefly
...
Thus,
although the sites might not have been typical huntergatherer home bases, it did appear that a connection existed
between the bones and the stones: the hominins almost
certainly were eating meat
...

Determining the identity of marks on the surface of fossil
bones is an important taphonomic activity: gnawing carnivores and nibbling porcupines can all leave their signatures
...
In 1986,
Behrensmeyer and two colleagues from the Smithsonian
Institution reported that bones trampled in sandy sediment
can sustain abrasions that are virtually indistinguishable
from genuine stone-tool cutmarks
...
“If such evidence is combined with criteria based
on context, pattern of multiple marks and placement on
bones, however, it should be possible to distinguish the two
processes in at least some cases bearing on early human
behavior
...
2
...
For instance, Sandra Olsen and Pat Shipman
have examined the problem experimentally and stated:
“Macroscopic and microscopic comparison of experimentally
trampled bones and those which have had soft tissue
removed with a flint tool demonstrate significant differences
between the surface modifications produced by the two
processes
...
2 Bone surfaces under the electron microscope:
(a) The surface shows the round-bottomed groove made by a hyena
gnawing at a modern bone
...
(c) This fossil bone from
the Olduvai Gorge carries carnivore tooth marks (t) and stone flake
grooves (s); the scavenger activity followed the hominin’s activity
on this occasion
...
)

• What is implied by the fact that the great majority of hominin
fossil remains have been recovered from sediments laid down near
sources of water, such as streams and lakes?
• Why is the fossil record of the African great apes virtually nonexistent for the past 5 million years—during which time the hominin
record is relatively good?
• Fossil fragments from almost 500 hominid individuals representing perhaps four species over a period of 4 million years ago to 1
million years ago have been recovered from the Lake Turkana
region of Kenya
...
Taphonomy and the fossil record
...

Behrensmeyer AK, Hill AP
...
Chicago: The
University of Chicago Press, 1980
...
Paleoenvironmental contexts and
taphonomic modes
...
Terrestrial ecosys-

59

tems through time
...

Olsen SL, Shipman P
...
J Archeol Sci
1988;15:535–553
...
Life history of a fossil
...

Tappen M
...
Curr
Anthropol 1995;36:223–260
...
Grasping hands,
enlarged brain, hindlimb-dominated locomotion, and low reproductive potential are some of the characteristics that define what it is to be
a primate
...


Homo sapiens is one of approximately 200 species of living
primate, which collectively constitute the order Primates
...
) Just as we, as individuals, inherit many resemblances
from our parents but also are shaped by our own experiences, so it is with species within an order
...

Matt Cartmill, of Duke University, says of anthropology:
“Providing a historical account of how and why human
beings got to be the way they are is probably the most important service to humanity that our profession can perform
...
In this unit we will
consider what it is to be a primate, in terms of anatomy and
behavior
...
First,
ecological research has been thoroughly incorporated into
primate studies
...
Second,
the science of sociobiology has enabled a keener insight
into the evolution of social behavior (see unit 13)
...
Modern
primatology therefore promises to serve as the focus of some
of the most serious intellectual challenges of behavioral
ecology
...

(Monkeys and apes are known collectively as anthropoids
...

Apart from humans, there are no native, modern primate
species in Europe, North America, or Australia
...
1
...

Some species are among the most generalized and primitive
of all mammals, while others display specializations not seen
in other mammalian orders
...
True, some have lost tails and others
have developed large brains
...

Modern primates vary enormously in size, ranging from
the diminutive mouse lemur, which weighs in at 80 grams,
to the male gorilla, at more than 2000 times the mouse
lemur’s size
...
2)
...
Several Old World monkeys and
one apeathe mountain gorillaalive in temperate and even
subalpine zones
...


10: Primate Heritage
Baboon

Lemur

Orangutan Gorilla

61

Human

Present

20

30

ians
Prosim

Time (millions of years ago)

10

Colobus monkey
Chimpanzee

New W
orld m
onke
ys
Ol
dW
or
ld
mo
nk
ey
s

Tarsier Spider
monkey

ids

Gibbon

no
mi

Ho

40

50

Figure 10
...


60

Figure 10
...


Definition of primate
Although humans have clearly departed from our primate
roots in colonizing so broad a range of habitats, many of
the characteristics that we often envision as separating us
from other primatesasuch as habitual upright walking, great
intelligence, and more complex forms of social organization
and behavior socialityaare actually extensions of, rather
than discontinuities with, what it means to be a primate
...
“It has, in fact, been a common theme throughout
the literature on primate evolution that primates lack any
clear-cut diagnostic features of the kind found in other
species of placental mammals,” notes Robert Martin, of the
Field Museum, Chicago
...
” If one looks at living primate species

New World monkeys
Lemurs
Old World monkeys and apes

instead, encompassing all aspects of their anatomy and
behavior, a definition constructed from universal or nearuniversal characteristics is possible, says Martin
...

It goes on to describe features of hand and foot anatomy,
overall style of locomotion, visual abilities, intelligence,
aspects of reproductive anatomy, life-history factors (such as
longevity and reproductive strategy), and dental architecture
...
The University of Sussex
anthropologist Alison Jolly recently noted, “If there is an
essence of being a primate, it is the progressive evolution of
intelligence as a way of life
...

Primate hands and feet have the ability to grasp and are
therefore equipped with opposable thumbs and opposable
great toes
...
3 Modes of primate
locomotion: The monkey (top right) walks
quadrupedally, while the gibbon (top left) is
an adept brachiator (it swings from branch
to branch like a pendulum)
...
The gorilla (bottom
left), like the chimpanzee, is a knucklewalker (it supports its weight through the
forelimbs on the knuckles of the hand
rather than using a flat hand as the monkey
does)
...
The hominin
(right) is a fully committed biped
...
(Courtesy of John
Gurche/Maitland Edey
...
In modern primates,
fingers and toes have nails, not claws; and finger and toe pads
are broad and ridged, which aids in preventing slippage on
arboreal supports and in enhancing touch sensitivity
...

Primate locomotion is hindlimb-dominated, whether it
consists of vertical clinging and leaping (various small species), quadrupedal walking (monkeys and the African great
apes), brachiation (apes), or bipedalism (humans)
...
(See figure 10
...
)
It also means that the body is frequently held in a relatively
vertical position, making the transition to habitual bipedalism in humans a less dramatic anatomical shift than is often
imagined
...
In all primates, the two eyes
have come to the front of the head, producing stereoscopic
vision, to a greater extent than in other mammals
...
The shifting of the eyes from the side of
the head to the front, combined with the diminution of olfaction, produces a shorter snout; this character is accompanied
by a reduction in the number of incisor and premolar teeth
from the ancestral condition of three incisors, one canine,
four premolars, and three molars (denoted 3
...
4
...
1
...
3
...
) (See figure 10
...
)

M3
3
Hylobates dental
formula
2
...
2
...


C1
1

I2
2

I1
1

M2 M1 P4 P3
3
2
1 4

2
...
2
...


Figure 10
...
First, their extreme hardness means that they are the most
common item recovered from the fossil record, and hence provide
a disproportionate amount of information about fossil species
...

By convention, dental formula is written as shown in the diagram
...
(Courtesy of John Fleagle
...
This
increase also reflects a greater “intelligence
...
Tied to this
enhanced encephalization is a shift in a series of life-history
factors: animals with large brains for their body size tend to
have a greater longevity and a low potential reproductive
output
...
“Primates are, in short, adapted for slow
reproductive turnover,” observes Martin
...
For
instance, a quarterback would not be able to stand behind his
offensive line and accurately throw a deep pass, unless he
were a primate
...
More historically, when hominins
first began making stone tools, they were not “inventing
culture” in the sense that is often used, but merely applying
primate manipulative skills to a new task
...

Later we will return to some of these and other themes,
particularly the issue of life-history strategy and brain size
(see units 12 and 31)
...


Theories of the origin of primate
adaptations
The first systematic attempt to account for the differences
between primates and other mammals was made by T
...

Huxley, in his 1863 book, Evidence as to Man’s Place in Nature
...
Ancestral primates and, by extrapolation, humans
were different from other mammals, they argued, because of
adaptation to life in the treesahence the arboreal hypothesis of primate origins
...

As Cartmill noted, however, “The arboreal theory was
open to the most obvious objection that most arboreal mammalsaopossums, tree shrews, palm civets, squirrels, and so

63

onalack the short face, close-set eyes, reduced olfactory
apparatus, and large brains that arboreal life supposedly
favored
...

In any case, the arboreal theory was modified and extended
in the 1950s by another British researcher, the eminent
Sir Wilfrid Le Gros Clark
...

In reassessing the arboreal theory in the early 1970s,
Cartmill applied biologists’ most powerful toolacomparative
analysis
...
In other words, if primates are truly the ultimate in
adaptation to arboreal life, you would expect that they would
be more skillful aloft than other arboreal creatures
...
Squirrels, for instance, do exceedingly well
with divergent eyes, a long snout, and no grasping hands
and feet, often displaying superior arboreal skills to those of
primates
...

If the close-set eyes and grasping hands and feet were an
adaptation to something other than arboreality, what was it?
Once again Cartmill used the comparative approach to find
an answer that formed the basis of the visual predation
hypothesis
...

Cartmill sought individual elements of the primate suite in
a range of other species
...
Some South
American opossums show similar behavior, capturing their
prey by hand or mouth
...

“Most of the distinctive primate characteristics can thus
be explained as convergence with chameleons and small
bush-dwelling marsupials (in the hands and feet) or with cats
(in the visual apparatus),” concluded Cartmill
...
” These species should not be considered “living fossils”
because, like humans, they are also the products of 60 million years of evolution
...

Cartmill’s visual predation hypothesis has recently been
challenged by American primatologist Robert Sussman
...
He
also argues that the earliest primates evolved at a time when
flowering plants were in the midst of an evolutionary diversification
...
Sussman’s hypothesis is obviously
similar in some ways to the earlier arboreal hypothesis
...
In any case, a 2002 report in Science of
a 55-million-year-old primate fossil from Wyoming points to
an ancestor adapted to hanging tightly onto tree branches
...
”
Insects, gums, fruit, leaves, eggs, and even other primatesa
all are found on the menu of one primate species or another,
and most species regularly consume items from two or more
of these categories
...

Small species have high energy requirements per unit of
body weight (because of a high relative metabolic rate), and
they therefore require food in small, rich packets
...
Because of
their reduced relative energy demands, large species have
the luxury of being able to subsist on bulky, low-quality
resources, which are usually more abundant
...

A good deal of variation upon this basic equation exists,
however
...
” What sets the basic
equation, she says, is “how they make up the difference in
energy and how they meet their protein requirements
...


The origin and evolution of primates
The overall evolutionary pattern of primates remains unsettled (see figure 10
...
Some
kind (or kinds) of species ancestral to all primates survived
the mass extinction 65 million years ago that spelled the end
of the Age of Reptiles, with the dinosaurs being the most
notorious of the extinctions
...
The 200 modern species repres-

(a)
Lemurs and lorises

Tarsiers

Anthropoids

Adapid
group
Omomyid
group

(b)
Tarsiers

Lemurs and lorises

Omomyid
group

Anthropoids

Adapid
group

(c)
Lemurs and lorises

Tarsiers

Adapid
group

Omomyid
group

Anthropoids

“Third
group”?

?

Figure 10
...
Until
recently most opinion was divided between schemes (a) and (b),
which show differences over the origin of anthropoids
...
Based on the
most recently discovered fossil evidence, however, scheme (a) is
now most strongly supported
...

The known fossil record provides only the briefest of
glimpses of this radiation, a sketchy outline at best; somewhere between 60 and 180 fossil primate species can be
recognized
...
6 Primate classification
...
The plesiadapiforms
constituted a successful group living in the Paleocene and
early Eocene (55 to 65 million years ago) of North America
and Europe, amounting to some 25 genera and 75 species
...
Most members of the group
were probably insectivores
...
In
other respects the plesiadapiforms are somewhat specialized,
including the possession of large anterior teeth and three or
fewer premolars (many of the earliest prosimians have four
premolars)
...
Some researchers contend,
however, that the plesiadapiforms were not primates at all,
but instead are linked with the modern colugo (also misleadingly called flying lemurs)
...
These advances are helping to resolve the early history of the group, extend its known geographic range, and
root its origins and diversification deeper in the past, perhaps
even before the end-Cretaceous extinction
...
The species, which is estimated to have
weighed less than 100 grams, is thought to belong to the
family Omomyidae, one of two major groups of early, true
primates
...
The omomyidsatiny, nocturnal,
fruit-eating speciesaare considered to be ancestral to tarsiers
...
An

Suborder

Catarrhini

Ceboidea Cercopithecoidea Hominoidea
Tarsiers New World
monkeys

65

Old World
monkeys

Apes and
humans

Infraorder

Superfamily
Common
names

adapid specimen was found early in the nineteenth century
...

One of the most spectacular discoveries, announced in 1994,
included five new types of early primate, of both omomyid
and adapid affinities, at the Shanhuang site in southeastern
China
...
One of the most interesting finds
involved teeth that are virtually identical to those of modern
tarsiers
...
The Chinese find indeed
implies the modern tarsier might be a “living fossil
...
) (See figure 10
...
)
Uncertainty has long swirled around the evolutionary root
of the suborder Anthropoidea (monkeys, apes, and humans)
...
Both
schemes put the origin of anthropoids close to 35 million
years ago
...
Algeripithecus minutus, discovered in Algeria
and reported in May 1992, is suggested to be a specimen of
the latter group
...
The dental
formula of one specimen, Eosimias, is what would be expected
of an ancestral anthropoid (hence its name)
...
It now seems likely that
modern tarsiers and modern anthropoids shared a specific
common ancestor
...


66

Part Two: Background to Human Evolution

The earliest known fossil of the superfamily Hominoidea,
which includes all living and extinct species of humans and
apes, is some 20 million years old; it was found in Africa (see
unit 16)
...

2002;298:1606–1610
...


Science

Cartmill M
...
Evol Anthropol
1992;1:105–111
...
Primate adaptation and evolution
...

Fleagle JG, Kay RF
...
New York: Plenum Press,
1994
...
Rethinking anthropoid origins
...

Kay RF, et al
...
Science 1997;275:797– 804
...
Primates: a definition
...
Major topics in primate and human evolution
...

———
...
Nature 1993;363:223–
234
...
Primate origins and adaptations
...

Sussman RW
...
Am
J Primatol 1991;23:209–223
...
Using the fossil record to estimate the age of the
last common ancestor of extant primates
...


PART 3

HUMANS AS
ANIMALS
11
12
13
14

Bodies, Size, and Shape
Bodies, Brains, and Energy
Bodies, Behavior, and Social Structure
Nonhuman Models of Early Hominins

BODIES, SIZE,
AND SHAPE

11

The evolution of body size and shape is influenced by many factors,
including prevailing climate (reflecting body heat production and dissipation) and lifestyle activities (reflecting strength required for subsistence)
...
Homo sapiens individuals
were less robust and taller than Neanderthals when they arose
...
An
understanding of anatomical adaptation of many animal
species to different climates has a long history, with two
specific “rules” relating to this issue
...
1a)
...
1b)
...
Interest in this relationship emerged in
the 1950s and 1960s, when climate began to be recognized as
an important influence in determining anatomical differences among different geographical populations
...

In recent years, Christopher Ruff, of Johns Hopkins
University, has been bringing together the study of ancient

and modern human variation in relation to climate
...
The link between anatomy and climate relates to thermoregulation, or the balance between heat
produced and the ability to dissipate it
...
In hot climates, a high ratioathat is, a
large surface area relative to body mass, or a slim, long trunk
afacilitates heat loss
...
Simple geometry shows that the
ratio of surface area to body mass is high when the cylinder is
narrow, and low when it is wide
...
(See figure 11
...
)
A strong prediction flows from this analysis: people living
at low latitudes will have narrow bodies and a linear body
build, while those at high latitudes will have wide bodies and
a relatively bulky stature
...
He also discovered that Allen’s rule
applies convincingly, with tropical people having longer,
thinner limbs, which maximizes heat loss, while people at
high latitudes have shorter limbs
...
(See figures 11
...
4
...
A further step of simple
geometry shows that linearity is not a necessary feature of
low-latitude populations
...
2 shows
...
This fact is
revealed in a comparison of Nilotic people, whose average

70

Part Three: Humans as Animals

(a)

2

1
2
1
1

2

Mass = 1
Surface area = 6
Surface area/mass = 6

Mass = 8
Surface area = 24
Surface area/mass = 3

(b)

1

...
5
Surface area/mass = 8
...
Why the difference in stature? (See
figure 11
...
)
The answer is related to efficiency of heat dissipation
...

Nilotics live in open environments, where sweating is efficient; in contrast, Mbuti Pygmies, like most Pygmy populations, live in moist, humid forests, where the air is still and
sweating is an inefficient cooling mechanism
...
With the
width of the cylinder remaining constant, this requirement
implies a reduction of its lengthain other words, reduced
stature
...
5

Figure 11
...
(b) Allen’s rule:
An elongated shape increases the ratio of
surface area to mass; in humans, this
relationship is reflected in limb length
...
6)
...
This observation makes sense because, living in East
Africa as they did, they were exposed to a tropical climate
(albeit more than a million years apart)
...

Lucy and her companions, by contrast, may have inhabited
more closed, forested environments, comparable with the
environment of modern Pygmies
...
The frigid conditions under which the Neanderthals
evolved is reflected in their wide bodies and their relatively
short limbs, characteristics comparable to those seen in modern Eskimos
...
078x + 24
...
866 (p < 0
...
4 Relationship between body breadth and
latitude: People living at high latitudes have broad bodies, as
measured by the bi-iliac (pelvic) breadth; those residing at low
latitudes have narrow bodies
...
(Courtesy of C
...
Ruff
...
2 The cylindrical model of body shape: An increase
in the length (L) of the trunk has no effect on the ratio of surface
area to body mass
...
B
...
)

280

260

240
y = –0
...
649 (p < 0
...
3 Relationship between the ratio of surface area
to body mass and latitude: People living at high latitudes have
a low ratio as a consequence of Bergmann’s rule
...
B
...
)

We now turn to changes in body form of humans through
time
...
In this case, we are talking about people having thick
skulls and heavily muscled limbs
...
) These people were immensely
strong, reflecting their arduous subsistence pattern
...
(As mentioned earlier, the
early anatomically modern people in Europe were also more
linear, because of their African origin
...
Australian Aborigines,
Patagonians, and Fuegans, for instance, are still relatively
robust in their skull and skeletal anatomy
...
Reductions in brain size (to
1300 cubic centimeters), size of teeth and jaws, and overall
stature followed similar patterns, but to different degrees
...
5 Body outlines of modern populations: Figures
below the outlines give the surface area to body mass ratio (cm2/kg)
...
The
Pygmy has the same body breadth as the Nilotic and a similar ratio
...
B
...
)

For instance, in his studies of Australian populations, Peter
Brown, of the University of New England, Armidale, found
the following changes in the five millennia after the Ice Age:
tooth reduction, 4
...
5 percent; and stature reduction,
7 percent
...
Whatever
the details of the timing of events in these later stages, it
seems irrefutable that, until the nutritional effects of the last
century or so kicked in, modern people were comparative
midgets on the human evolutionary stage
...
7
...
Musclesanot missilesawere their weapons
...
For

KNM-WT 15000
Nariokotome boy
(307)

AL 288-1
Lucy
(320)

Figure 11
...

(Courtesy of C
...
Ruff
...
The conflicts arose, he says, because the groups were dominated by
bands of males, probably closely related, who sought to
appropriate the plentiful resources in their area, including
females from other groups
...
One key invention involved projectiles, spears in which stone points were hafted onto wooden

11: Bodies, Size, and Shape 73
43
ME

Maximum tibial length (cm)

EUP
LUP

38

Mes

Modern tropical
Modern higher latitude

ME
Eur

33
ME
Eur
EUP
LUP
Mes

28
35

40

KNM-WT 15000
Neanderthal
Early modern Homo sapiens
Middle Eastern
European
Early Upper Paleolithic
Late Upper Paleolithic
Mesolithic

45
50
Maximum femoral length (cm)

Figure 11
...
The
dotted line represents the division between modern tropical and
high-latitude populations
...
European (open triangle, Eur) and Middle
Eastern (open triangle, ME) Neanderthals had relatively short legs;
early African Homo (closed triangle, KNM-WT 15,000, the Turkana
boy) had relatively long legs
...
(Courtesy of C
...
Ruff
...
Stone tools became more versatile, which perhaps
buffered people from some bare-hands contact with their
environment
...
Loring
Brace, of the University of Michigan, has long been a proponent of technology, or culture, as an important force in
diminishing human robusticity
...
This development
emerged at different times in different parts of the world
...

Many dramatic changes transpired with the end of the Ice
Age, not least of which was the disappearance of plentiful
game, some of it very large
...
Foley suggests that this reduction of
resources forced recourse to one of two subsistence strategies
...
Although we now
think of agriculture as producing plentiful food, early food
production was a hazardous venture, with many lean times
...

In the second strategy, because male hunters were unable
to monopolize food resources to the same degree as their
ancestors had done, they were unable to monopolize many
females as mates (a practice known as polygyny)
...
Thus, males became smaller because they didn’t
need to fight as much
...
Limitations on resources often lead to reduced
body size, says Christopher Stringer, of the Natural History
Museum, London, as is seen in the dwarfing of species on
islands
...
Early
weaning inevitably leads to a reduction in brain size, though
not, says Martin, necessarily to a reduction in body size
...

The advent of agriculture was once viewed as the universal
change in human culture that produced a universal change
in human physique
...
Agriculture was developed at different times in different parts of the world, and in
some places not at all
...
The one change that applies
everywhere, of course, is the increase in global temperature
associated with the end of the Pleistocene
...
Moreover, body size reduction has occurred
in many nonhuman animals in this same period, in Australia,
Israel, and Indonesia, for example
...


KEY QUESTIONS
• Why is local climate such a strong predictor of body form for
human populations in different parts of the world?
• How is subsistence pattern superimposed on climatic adaptation
in relation to body form?
• What problems are encountered in reconstructing the body form
of extinct human species?
• What is the most likely explanation of the reduction of robusticity
in recent human populations?

74

Part Three: Humans as Animals

KEY REFERENCES
Aiello LC
...
J Human Evol 1992;22:127–147
...
Lower limb length of European early modern humans in relation to mobility and climate
...

Kappelman J
...
J Human Evol 1996;30:243–276
...
Behavioral ecological implications of early hominid
body size
...


Ruff CB
...
Yearbook Physical Anthropol 1994;37:65–107
...
Variation in human body size and shape
...

Ruff CB, Walker A
...
In: Walker A, Leakey
R, eds
...
Cambridge, MA:
Harvard University Press, 1993:234–265
...
Body mass and encephalization in Pleistocene Homo
...

Smith RJ
...
Curr Anthropol
1996;37:451–481
...
Large animals mature late,
have long gestations, small litter sizes, long lactation periods, long
interbirth interval, and long lifespans
...
Hominins are relatively large animals, with life histories as
just described
...

Life-history variables are those factors that describe how
individuals of a species proceed from infancy through maturity to death, and the strategies involved in producing offspring
...

In 1978, Princeton ecologist Henry Horn encapsulated the
range of potential ecological options by posing the following
set of questions: “In the game of life an animal stakes its offspring against a more or less capricious environment
...
What
is an appropriate tactical strategy for winning this game?
How many offspring are needed? At what age should they
be born? Should they be born in one large batch or spread
out over a long lifespan? Should the offspring in a particular
batch be few and tough or many and flimsy? Should parents
lavish care on their offspring? Should parents lavish care on
themselves to survive and breed again? Should the young
grow up as a family, or should they be broadcast over the landscape at an early age to seek their fortunes independently?”
In responding to these challenges, the animal kingdom as a
whole has come up with a vast spectrum of strategies, ranging from species (oysters, for instance) that produce millions
of offspring in a lifetime, upon which no parental care is
lavished, to species (such as elephants) that produce just
a handful of offspring in a lifetime, each born singly and
becoming the object of intense and extensive parental care
...


Primates as large mammals
By their nature, mammals are constrained in the range
of life-history patterns open to them: mammalian mothers
are limited in the number of offspring that can be carried
successfully through gestation and suckling
...

In the order Primates, potential reproductive output is low
compared with that of mammals as a whole, with litters
being restricted in the vast majority of species to a single offspring
...
(Species with a high potential reproductive output are described as being r-selected
...

(See table 12
...
)
Within the overall Primate order, however, a wide range of
life-history patterns exists, as biologists Paul Harvey, Robert
Martin, and Tim Clutton-Brock have pointed out
...
On the other hand, adult female
gorillas [the largest species of primate] produce a single offspring every 4 or 5 years, and the young do not breed until
they are about 10 years old
...
1
...
“Such differences between
species have presumably evolved as adaptations for exploiting different ecological niches,” note Harvey and his colleagues
...
1 Characteristics of r- and
K-selection: r-selected species (such as
oysters) live high-risk lives and are more
affected by external factors than by
competition from within the population
...
Primates as a
whole, and apes and humans in particular,
are K-selected
...
1 A difference in body sizes: The gorilla and the
mouse lemur represent the largest and the smallest of the primates,
with the females of the species weighing 93 kilograms and 80 grams,
respectively
...
One of the most
dramatic involves potential reproductive output: the female mouse
lemur can grow to maturity and, theoretically, leave 10 million
descendants in the time it takes a female gorilla to produce a single
offspring
...
”
Success in simple Darwinian terms is often measured in
the currency of reproductive output, which is determined by
a series of interrelated life-history factors
...
(See
figure 12
...
)
Some species live “fast” livesaduring their short lifespan,
they mature early, produce large litters after a short gestation
period, and wean early
...
Other species live “slow” livesaduring their
long lifespan, they mature late, produce small litters (a single
offspring) after a long gestation period, and wean late
...

As it happens, the best predictor as to whether a species
lives “fast” or “slow” is its body size
...
(See figure 12
...
) As
potential reproductive output is highest in species that
experience fast lives, it might seem that all species would be
small
...

Such benefits might include (for a carnivore) a different
spectrum of prey species or (for a potential prey) better
antipredator defenses
...
Basal energy demands increase as the 0
...
2 Life-history factors: Body
size affects a broad range of life-history
factors, as illustrated here
...


Interbirth interval

Lactation period

Large body size

Longevity

Small body size

Cetacea
Proboscidea
Artiodactyla
Carnivora
Primates

Figure 12
...
Nevertheless, the
biology of hominoids is the biology of large
mammals
...


Rodentia
Chiroptera
Insectivora
1g

10 g

basal energy requirement per kilogram of body weight decreases,
a relationship known as the Kleiber curve
...
A further potential benefit of increased body
size is improved thermoregulatory efficiency
...
Any
particular body size increase is associated with a more or less
predictable change in, for example, gestation length, and age
at maturity
...
75 for
basal energy needs, 0
...
56 for weaning age, and so on)
...
This examination
amounts to analyzing how far particular features depart from
predictions based on body size
...
That is, all figures for each life-history variable
would fall on the appropriate straight lines
...
This variation reveals an individual species’ (or, more usually, a group of related species’)
adaptive strategy
...


Altricial and precocial strategies
Among mammals as a whole, a key dichotomy exists
in developmental strategy that has important implications
for life-history measures: the altricial/precocial dichotomy
...
The young of precocial species, on the other hand, are relatively mature and
can fend for themselves to a certain degree
...
In altricial species,
gestation is short and neonatal brain size is small
...
There is, however, no consistent difference in adult
brain size between altricial and precocial species
...

In addition to the distinction between fast and slow
lives based on absolute body size, some species’ lives may
be fast or slow for their body sizes
...
According to this theory, environments that are
unstable in terms of food supply (that is, are subject to
booms and busts) encourage r-selection: fast lives, with high
potential reproductive output
...

As mentioned earlier, primates are close to the K-selection
end of the spectrum among mammals as a whole, but
some primates are less K-selected than others
...

A second factor that influences whether a species might
live relatively fast or slow for its body size has been identified
by Paul Harvey and Daniel Promislow
...
” In other words, species that suffer
high natural rates of mortality live fast
...
”
Again, does the very slow life lived by Homo sapiens imply
evolution from an ancestor that experienced very low levels
of mortality?
Given that most mammals measure less than 32 centimeters in length, homininsaeven the early, small speciesa
must be classified as large mammals
...
7 meters (males) tall, and weighed some
30 to 65 kilograms (see unit 19)
...
5 million years ago and the
evolution of Homo erectus, which stood close to 1
...

(See unit 24
...
Surely, hominins lived slow lives in the terms of
life-history variables, with a vastly increased brain capacity
eventually distorting some of them
...

For instance, dietary scope could be broad; day and home
ranges could be large; mobility could be high; predator–prey
relations would be shifted from that of smaller primates;
thermoregulatory efficiency would be improved; sociality
would be extended; and enhanced encephalization would be
energetically possible
...
Much of human evolution may therefore be explained
in terms of a large hominoid exploiting a relatively stable
food supply, its stability perhaps being enhanced by virtue
of its breadth
...
A reduction in mortality, perhaps through improved
antipredator defense, would further encourage a “slow” lifehistory strategy
...


12: Bodies, Brains, and Energy

KEY QUESTIONS
• What are the limitations of a simple Darwinian measure of reproductive success?
• At any particular body size, which is the riskier strategy: living fast
or living slow?
• Primates as a group are twice as encephalized as other mammals
...
The evolution of human childhood
...

Charnov EL, Berrigan D
...
Evol Anthropol
1993;1:191–194
...
Humans before humanity
...

Harvey P, Martin R, Clutton-Brock T
...
In: Smuts BB, Cheney DL, Seyfarth RM, Wrangham

79

RW, Struthsaker TT, eds
...
Chicago: The University of Chicago Press, 1986:181–196
...
Comparing brains
...

Harvey P, Nee S
...
Nature 1991;350:23–
24
...
Life history theory and evolutionary anthropology
...

Kaplan H, et al
...
Evol
Anthropol 2000;9:156–185
...
Human bodies of evidence
...

Promislow D, Harvey P
...
J Zool Soc
London 1990;220:417–437
...
Environmental correlates of the intrinsic rate of natural
increase in primates
...

Ross C
...
Evol Anthropol 1998;6:54–62
...
Life history and the evolution of human maturation
...

Stearns SC
...
Oxford: Oxford University
Press, 1992
...
Social living has costs and benefits, but the ubiquity of
social living in primates implies that the benefits outweigh the costs
...


As highly social creatures ourselves, we may find it odd to
ask, Why should animals live in groups? This problem is, in
fact, a very good biological question because gregariousness
carries many costs
...
A lone individual
is not exposed to diseases that flourish in communities,
which provide a viable host pool for pathogens
...
Clearly, as most primates do live in
groups, the benefits must outweigh the costs
...
Whatever the size of the group, it serves as the focus of many
important biological activities, including foraging for food,
raising offspring, and defending against predators
...
The size,
composition, and activity of a group defines what is usually
meant by a species’ social organization
...
Consequently, an order
such as the Primates will display an astonishingly wide range
of social organization, in which even closely related species
may carry out their daily social lives in very different ways
...
Even if we consider just the
apesathe largest of the nonhuman primatesathe array of
social organization found in the species is as great as among
the primates as a whole
...
It will also examine
some of the consequences of group livinganot the costs
mentioned, but the ways in which individuals might adapt
behaviorally and anatomically to different types of social
structures
...

Gibbons and siamangs, the smallest of the apes (sometimes
called the lesser apes), live in forests in Southeast Asia
...
Gibbons are
territorial, and eat a diet of fruit and leaves
...
Mature males and females have
essentially the same body size
...

The other Asian ape, the orangutan, is much larger than
the gibbon and pursues a very different lifeway, although it
is also highly arboreal
...
The
mother and offspring occupy a fairly well-defined home
range, which usually overlaps with that of one or more
other mature females and their offspring
...
Males, which are
about twice the size of females, actively defend their territories against incursion by other males
...

Gorillas, the largest of the apes, live in the forests of central
and west Africa
...

Predominantly terrestrial animals that live on low-quality
herbage found in abundant but widely dispersed patches,
gorillas live in close groups composed of from 2 to 20 individuals
...
Mature males compete for control of the
group
...
New groups are established when a
lone silverback begins to attract transferring females
...

Chimpanzees, which are terrestrial and arboreal omnivores, live in rather loose communities composed of between
15 and 80 individuals, representing a mixture of mature
males and mature females and their offspring
...
The core of chimpanzee social life is a female with
her offspring; these units are often found by themselves but
sometimes link up with other females and their offspring
...
By contrast with
orangutans, single chimpanzee males do not maintain exclusive control of a group of female home ranges
...
Mating in chimpanzee
communities is promiscuous, with each estrus female copulating with several males
...

A key feature of chimpanzee social organization is that,
unlike in the general pattern of multimale societies among
primates, males remain in their natal group while young
adult females transfer (or are sometimes kidnapped) to other
communities
...
Adult male chimpanzees are typically 25 to 30
percent larger than females
...
1)
...
) This spectrum of social organization raises questions
about several aspects of group living
...
For each species, some kind of interaction
must take place between its basic phylogenetic heritageaits
anatomy and physiologyaand key factors in the environment
...
What else plays a part?
“There is no consensus as to how primate social organization evolves,” Richard Wrangham of Harvard University
observed, “but a variety of reasons suggest that ecological
pressures bear the principal responsibility for species differences in social behavior
...
As Wrangham explains, the problem is that “we do not
know exactly what the relevant ecological pressures are, or
which aspects of social life they most directly affect, or how
...

Even though it may be more conspicuous than a lone individual, a group can be more vigilant (more pairs of eyes and
ears) and more challenging (more sets of teeth)
...

It is certainly true that terrestrial species, which face
greater risk from predators than arboreal animals, live in
larger groups and commonly include more males in the
group; in addition, the males in such species frequently are
equipped with large, dangerous canine teeth
...
So, it is possible that terrestrial
primates evolved these characteristics for these other reasons;
once evolved, the properties proved highly effective in mitigating the threat of predation
...

Food distribution has also been suggested as a trigger of
social organization
...
1 Hominoid social organization: The range of
social organizations among the apes matches that found among
anthropoids as a whole
...
In gorillas, a single male
exerts control over a group of females (and their offspring); this
system is known as unimale polygyny
...
In chimpanzees, several related
males cooperate to defend a group of widely distributed females
(and their offspring); this system provides an example of multimale
polygyny
...
Wrangham has proposed a theory of social organization
that includes food distribution as a key influence, but the
focus of this model differs from that of earlier ideas
...
” In other

13: Bodies, Behavior, and Social Structure

:

Access to
mature females

:

Access to
food resources

Figure 13
...
By contrast, a male’s reproductive
success is limited by his access to mature females
...


words, whatever ecological setting a species might occupy,
the behavior of females is fundamental to the social system
that evolves within it
...
Access to mature males is not usually a
limiting factor, whereas access to food resources most certainly is
...

As a result, their reproductive success is determined by successful access to mature females
...
2
...
Any explanation of
why primates should form social groups at all must also

83

explain this asymmetry
...
Wrangham’s model does
offer an explanation, as follows
...

(See figure 13
...
) Food that comes in larger, defensible
patches can, however, support several mature females and
their offspring
...
Wrangham
suggests that the costs of competition within a group are
balanced against the benefits of cooperating with group
members to outcompete other groups for access to food
patches
...

Thus, when a species exploits food resources that come
in discrete, defensible patches, multifemale social groups
will evolve in which the females are closely related to one
another
...
Where do the males fit in? If patches of food
resources are relatively densely distributed, allowing a group
of females to defend them all and exercise territoriality, extra
males are somewhat extraneous and a unimale social system
usually forms
...
(See figure 13
...
) Indeed,
extra males can prove useful in the occasional competitive
encounters with other groups
...

In non-female-bonded systems, such as the chimpanzee
and orangutan, where food does not come in defensible
patches and females are mostly alone, the distribution of
males depends on whether they can defend a community
range alone or need the cooperation of other males
...
Again,
cooperation is most effective among relatives
...


Consequences of social organization
Given these underlying influences, says Wrangham, several
predictions can be made in terms of behaviors within and
between groups
...
Aggression within female-bonded groups should
arise over access to food resources, and females should play a
very active role in the encounters
...
These
predictions appear to have some support
...
Male primates
often must compete with other males for access to breeding
females, and the bigger their body size, the more likely they
are to succeed
...
Other factors that might be important in such
encountersacanine teeth, for exampleamay also become
exaggerated in males (see figure 13
...

In monogamous species, in which competition between
males is low or absent, males and females are typically the
same size
...
Enlarged
canines are also found in polygynous species
...
Species in which males typically control harems
of, for example, 10 females do not necessarily display greater

Monogamy
(Gibbon)

Figure 13
...
If a male can defend
a “community” of lone females, unimale
polygyny will result, as observed with the
orangutan
...
If a community of
females can be defended only by several
males, then a group of related males will
defend a number of unrelated females
(multimale polygyny), as observed in
chimpanzees
...

Although the notion that body size dimorphism represents
the outcome of competition among males for access to
females is popular among biologists, other explanations are
also possible
...
Once again, the problem of circularity arises here
...

Robert Martin of the Field Museum, Chicago, adds an
important note of caution to this discussion, noting that
perhaps our explanations have been too male-oriented in
seeking to explain why the male size has increased
...
“Smaller females may breed
earlier,” he notes; “selection for earlier breeding might
explain the development of sexual dimorphism in at least
some mammalian species
...


Single male can
assemble unrelated
females

(a)

Abundant, lowquality food

Females may or may
not be in groups

(Gorilla)

(b)

Unrelated males
form alliances to
defend females
High-quality food,
in occasional, large
patches

Related females form a
group to defend resources

Figure 13
...
A male
may be able to assemble a harem, as does the gorilla
...
Alliances among unrelated males
may form to defend the females from other males, as in savannah
baboons
...
5 Sexual dimorphism,
teeth, and bodies: In polygynous social
systems, the males are typically larger than
females, in terms both of body size and
canine teeth, as illustrated here for baboons
...
(Courtesy of John Fleagle/
Academic Press
...
Evolution of social organization
...

Dunbar RIM, Barrett L
...
New York:
Dorling Kindersley, 2000
...
Primate adaptation and evolution
...

Foley RA
...
In: Price CR, et al
...
Basel: Karger, 1994:27–36
...
Humans before humanity
...

Foley RA, Lee PC
...
Science 1989;243:901–906
...
Sexual dimorphism and reproductive
strategies
...
Human
sexual dimorphism
...

Lee PC
...
In: Slater PJB, Halliday TR,
eds
...
Cambridge, UK: Cambridge University Press, 1994:266–303
...
Socioecology and the ontogeny of sexual dimorphism in
anthropoid primates
...

Martin RD, et al
...

In: Short RV, Balaban E, eds
...

Cambridge, UK: Cambridge University Press, 1994:159–200
...
The road less travelled: phylogenetic perspectives in primatology
...

Rodseth L, et al
...
Curr
Anthropol 1991;32:221–254
...
Human behavioral ecology: II
...

Wooders M, van den Berg H
...
Economics Bulletin 2001;3:1–9
...
Evolution of social structure
...
,
eds
...
Chicago: The University of Chicago Press,
1987
...
In
the Homo lineage, mixed groups of males and females, with strong
male–male alliances, evolved over time
...
For instance, one can ask
questions about the social organization of the last common
ancestor between hominins and apes and of the early
hominins themselves
...
If the experience
of observing the behavior of modern ape species teaches us a
lesson, it is that we can expect different forms of social organization among different hominin species, depending on their
behavioral ecology
...
)

Three approaches to models
There are several ways in which modern primates can be
used to model the lives of the extinct species
...
Second, guided by phylogeny,
one can consider only the living African apes and humans
and seek commonalities of behavior that might therefore
have been present in a common ape/hominin ancestor
...


Primate models
The first of these three modelsathe specific primate modela
is the longest-established approach
...
It was
for this reason that Louis Leakey promoted the study of wild
apes, with Jane Goodall studying chimpanzees and Dianne
Fossey gorillas
...
(The very earliest hominins appear to have lived
in forest environments
...
A troop consists of mature
females (often related to one another) and their offspring,
and many mature males (unrelated to one another)
...
In other words, baboons
operate within a multimale, female kin-bonded social
organization
...
”
The chimpanzee has also been proposed as a model for the
last common ancestor and the early hominins, and for good
reason: it is our closest genetic relative, and it occasionally
hunts and uses tools
...
When, for
instance, a chimpanzee model is proffered, “an ape–human
dichotomy is created,” says Richard Potts, an anthropologist
at the Smithsonian Institution (Washington, DC)
...
”
Potts points out that the dentition of the early hominin
genus Australopithecusalarge, thickly capped cheek teeth set

88

Part Three: Humans as Animals
in robust jawsaresembles that of neither chimpanzees nor
humans, and therefore its diet and means of foraging were
probably different
...

The most recent entry into the primate model stakes is the
pygmy chimpanzee, or bonobo, which was proposed in 1978
by Adrienne Zihlman, John Cronin, Vincent Sarich, and
Douglas Cramer
...

The pygmy chimpanzee, which is now found only in a small
area in Zaire, is strikingly similar in overall body proportions
to the early hominin species, Australopithecus afarensis
...
Bonobos engage in
sex in every possible partner combination, often face-to-face,
usually as a way of reducing tension in the group
...
Nevertheless,
one must always remember that even closely related species
may exhibit distinctly different social structures when they
occupy different habitats
...
The case here is based upon strict analogy with
a supposed behavior: cooperative hunting
...
(See figure 14
...
)

Phylogenetic models

Figure 14
...
Here we see the pygmy chimpanzee (top left), the
common chimpanzee (top right), the savannah baboon, and the lion
(a social carnivore)
...
The rationale, as explained recently by Richard
Wrangham of Harvard University, is as follows: “If [a behavior] occurs in all four species, it is likely (though not certain)
to have occurred in the common ancestor because otherwise
it must have evolved independently at least twice
...
”
Wrangham examined 14 different behavioral traits, such
as social group structure, male–female interactions, intergroup aggression, and so on
...
On this basis Wrangham infers that
the common ancestor of hominins and African apes “had
closed social networks, hostile male-dominated intergroup
relationships with stalk-and-attack interactions, female

14: Nonhuman Models of Early Hominins
exogamy and no alliance bonds between females, and males
having sexual relationships with more than one female
...

But, for instance, it does seem to preclude the suggestion
made in 1981 by Owen Lovejoy that the then earliest known
hominin, Australopithecus afarensis, was monogamous and
nonhostile
...
The technique seeks to establish the range of
social structures that might have been available to hominin
ancestors, and then determine how these structures might be
altered in the face of changing environments
...
2
...
Just as ancestral anatomy
limits the paths of subsequent evolution, so too does ancestral social structure
...
In
other words, only certain evolutionary pathways are avail-

Figure 14
...
Species with different phylogenetic
constraints may therefore exhibit different social structures under
the same environmental conditions
...
Thus,
if you know where an ancestral species began among the
many possible social structures, you can predict the nature
of ecologically driven social change, because you know the
available pathways
...
1
...
The social structures

table 14
...
In the phylogenetic comparison, each of the 14 questions asks if a particular aspect of behavior exists in
all modern African apes
...
(Courtesy of
Richard Wrangham
...
In marked contrast with Old World monkeys, none of the apes show female
kin bonding or have a core of related females; and the African
apes involve a degree of male kin bonding
...
Toward
the end of the Miocene, approximately 10 million years
ago, a steadily cooling climate was reducing forest cover
...

Such an ecological shift would favor the evolution of a chimplike social structure: communities of dispersed females and
their offspring, with genetically related males defending the
community against males from other groups
...
As long as the cooling persisted, the ecological shift
would continue
...
Given the evolutionary pathways available under the
model, the larger social groups are more likely to be built
upon the male kin alliances rather than related females
...
The females and their offspring would
be forced to forage over larger areas to find dispersed and
seasonally limited food sources
...

Within the hominin species of 3 to 1 million years ago
there developed a degree of morphological diversity, presumably reflecting adaptation to different patterns of subsistence
...

Such foods tend to occur in large, widely dispersed patches
...

At the other extreme, Homo erectus evolved adaptations
including increased brain size and much reduced dental
apparatus
...
Instead of exploiting low-quality food

resources, its members increased their consumption of meat,
a patchily distributed but high-quality resource
...
This would
compromise males’ ability to defend females
...


The impact of brain enlargement
In addition to changes wrought by this subsistence strategy,
Homo would face another key change: the consequences of
brain enlargement
...
At some point it would have
become too expensive for the mother to provide for the offspring by herself, necessitating paternal involvement, strengthening male–female bonds
...

The 20 percent body size dimorphism in modern humans
would indicate a degree of male–male competition in our
recent past, not monogamy
...
One further factor is the size of the testes, an
indicator of subtle competition among males in multimale
groups
...
One way that an individual male might
outcompete his fellows is to produce more sperm in his
ejaculate
...

What of Homo sapiens? Human testes are small as well,
apparently ruling out competition in promiscuous, multimale groups
...
But, as Robert Martin
and Robert May commented recently, “these biological
antecedents are today often overlain by extremely powerful
socioeconomic determinants
...
Hunting strategies of Gombe and Tai chimpanzees
...
, eds
...
Cambridge, MA:
Harvard University Press, 1994:77–91
...
An evolutionary and chronological framework for human
social behavior
...

Kinzey W
...
New York: SUNY
Press, 1987
...
Meat-sharing as a coalition strategy by an alpha male
chimpanzee
...
, eds
...
Tokyo: University of Tokyo Press, 1992:159–174
...
Reconstructions of early hominid socioecology: a critique of
primate models
...
The evolution of human

91

behavior: primate models
...

Rodseth L, et al
...
Curr
Anthropol 1991;32:221–241
...
Chimpanzee hunting behavior
...

de Waal FBM
...
Sci Am March 1995:82–88
...
The significance of African apes for reconstructing
human social evolution
...
The evolution of human
behavior: primate models
...

Zihlman AL, et al
...
Nature
1978;275:744–746
...
Until relatively recently, the great apes were
considered each other’s closest relatives, with humans being separate
...


The superfamily Hominoidea (colloquially, hominoids)
includes all living and extinct ape and human (hominin)
species
...
Unit
16 will examine our knowledge of extinct ape species and
their possible relationship to living hominoids
...
This conclusion is based
principally on comparative anatomy of the hominoids
...

(It seems now to have been resolved, principally based on
molecular evidence
...
1 and 15
...
3)
which has a thin layer of enamel on the cheek teeth
...
In several cladistic analyses of living hominoids (by, for
example, Lawrence Martin of the State University of New

York at Stony Brook and Peter Andrews of the Natural
History Museum, London), the shared limb anatomy and
dental features of African apes were judged to be derived
characters that linked chimpanzees and gorillas as a separate
clade from humans
...
A
second schemeaa trichotomy in which African apes and
humans diverged simultaneously from a common ancestora
was also said to be possible, though less likely
...
For instance, one cladistic analysis grouped the
orangutan with the African apes in a clade separate from
humans, while another identified an African ape clade and a
human/orangutan clade
...
That is, gorillas were suggested to have diverged first
from the hominoid ancestor, with humans and chimpanzees
sharing a common ancestor from which they later diverged
...
4) As we shall see, this counterintuitive view
was also emerging from molecular studies of the time, and it
became ever more strongly supported throughout the following decade
...
If the
human/chimpanzee association was indeed correct, then
morphologists faced awkward puzzles
...
Furthermore, why have the

96

Part Four: Hominin Beginnings
Adaptations to bipedal locomotion
Head held vertically

Large, bulbous cranium
Short face
Reduced anterior
dentition, small
canines, large cheek
teeth coverd with
thick enamel

Reduced lower back
Short, wide pelvis

Shortened forelimb

Femoral head angled
and strengthened

Hand with enlarged
thumb, enhanced
fingertip sensitivity,
non-curved fingers
(a manipulative, rather
than a locomotor,
structure)

Increased hindlimb
length
Increased valgus
angle of knee
Foot forms a platform
structure with
non-opposable
great toe
...
1 Ape and human anatomy: The ape (left) is adapted
to a form of quadrupedalism known as knuckle-walking, which is
seen only in chimpanzees and gorillas
...


The wrist and elbow anatomy is adapted so as to “lock,” thus
providing a firm support for the body weight
...
Anthropologists are divided over
whether the common ancestor of humans and African apes was a
knuckle-walker
...
Recently, however, analyses of fossil and living
hominoids have added further evidence related to this point
...
He concluded that many characters in
gorilla once considered to be derived are actually primitive,
and that humans, chimpanzees, and australopithecines share
several characters that are derived for the group as a whole
...


Toe bones

Molecular studies
Human

Gorilla

Figure 15
...
A key difference, therefore, is in the relationship of
the great toe to the other toes of the foot
...


The term “molecular anthropology” was coined in 1962 by
Emile Zuckerkandl, who, with Linus Pauling, invented the
notion of using molecular evidence to uncover evolutionary
histories (see unit 8)
...
As mentioned earlier

15: Ape and Human Relations: Morphological and Molecular Views

Ape

Laetoli-Hadar
Dental arcade and diastema

Chimpanzee upper jaw

A
...
3 Palate and tooth anatomy: In apes, the jaw is
U-shaped; in modern humans and later extinct hominins, it is
parabolic
...
Ape incisors are large
and spatulate; a gap, the diastema, separates the second incisors
from the large canine; the premolars and molars have high cusps
...
4 Cladogram of catarrhine relations: This analysis
of 264 morphological characters leads to a chimpanzee/human
association as the most parsimonious tree; a tree with a hominoid
trichotomy is less parsimonious
...
(Adapted from Shoshani et al
...
In Australopithecus
species, the incisors are larger than in modern humans, as are the
canines; a diastema is sometimes present in early species; the
premolars and molars are large with low cusps
...
(Courtesy
of Luba Gudz
...
They used immunological reactions of certain blood proteins to measure genetic distances among the
living hominoids
...

As with all such calculations, Wilson and Sarich calibrated
their molecular clock using known (or assumed) divergence
times derived from the fossil record
...
According to their research, the genetic distance
between humans and African apes was one-sixth of that
between living African hominoids and Old World monkeys
...
5)
...
Although their results are by no
means unanimous, the great majority of these techniques

98

Part Four: Hominin Beginnings

Ramapithecus

Human

have supported the human/African ape linkage and have
yielded a divergence time of between 5 and 7 million years
ago
...

Much controversy surrounded this work, and not all disagreements pitted molecular biologists against morphologists
...
Supporters of the molecular clock (such as
Wilson) argued that the rate was constant and universal
...
Indeed,
Goodman initially attributed some of the surprisingly small
genetic distance between humans and African apes to a slowdown in the clock
...
By now, fluctuations
in the clock’s rate in general have been accepted, and a slowdown among hominoids in particular
...
For instance, using extensive DNA
sequences of certain globin genes, Goodman (previously a
critic of the clock) and his colleagues recently calculated the
human/chimpanzee divergence as 5
...

During the first two decades of molecular anthropology,
the vast majority of work agreed on two things: the reality
of a human/African ape affinity and an inability to break
the trichotomy
...
In the mid-1980s, evidence
began to build in favor of a tree with two divergence points:
the separation of the gorilla, followed later by a human/
chimpanzee split
...

Cladistic analysis requires specific characters (not genetic
distance); in this context, it means gene sequences
...
5 Ramapithecus
reconstructed: In the original
reconstruction of the two fragments of
upper jaw (maxilla) of Lewis’s Ramapithecus
specimen, the shape appeared to be
humanlike
...
The reconstruction was
inaccurate, in part because of missing
portions of the specimen
...
(Humans are known to share
98
...
5 percent identity in nuclear coding
sequences, or genes
...
This can yield a phylogenetic
pattern of the sort now heavily supported, even though the
evolutionary reality is a simple trichotomy
...

Imagine that an ancestral species possessed a gene A
...
Individuals in the population of the common ancestor may now possess two copies
of variant A (that is, homozygous for A), two copies of
variant A′ (homozygous for A′), or one copy of each variant
(heterozygous)
...
In
the population that leads to X, the variant A′ is lost, leaving
just A
...
A comparison of the sequences of this gene in
species X and Z would indicate that they diverged 10 million
years ago, despite the fact the speciation event occurred only
5 million years ago
...

What about species Y? If its population lost variant A, a
comparison of all three species would imply that Y is more
closely related to species Z than to species X; similarly, if Y lost
variant A′, it would appear to be more closely related to
species X than to species Z
...
(See figure 15
...
)
As this model indicates, for ancestral species possessing
many highly polymorphic genes, no simple, single picture
will emerge in a comparison of its descendants’ genes
...
6 Gene trees versus species
trees: Gene polymorphism in an ancestral
species followed by differential sorting of
variants can lead to erroneous conclusions,
regarding both the timing of divergence and
the relationship among descendant species
...
(b) Y looks more closely related
to Z than to X
...

(See text for details
...
7 Morphological versus
molecular views: The cladograms
show the current views that most
paleoanthropologists take on the two
approaches
...
Most molecular analyses favor
a human/chimpanzee clade
...

It is true that the gene tree/species tree problem can lead to
an erroneously old divergence date
...
How is
hominoid history to be assessed, given the data to hand?
The processes involved are stochastic, in terms of the
timing of the origin of polymorphisms and the subsequent
sorting of variants
...
The fact that so many data sets point to a
similar divergence time for the inferred human/chimpanzee
split provides some confidence in that date, unless all genes
just happened to have produced polymorphisms at the same
time in the ancestral species prior to speciationaan unlikely
event
...
Given the stochastic nature of the sorting
of variants, there is a one-third probability of genetic data
implying a human/chimpanzee alliance and a two-thirds
probability of seeing chimpanzee/gorilla or human/gorilla

Majority molecular view

alliances
...

In other words, the observed pattern is very likely to reflect
history rather than being a statistical quirk
...
7
...
5 and 8 million years is
still sparse
...
As a result, the common ancestor is now widely believed to have been intermediate in size between the gibbon and the chimpanzee; it
is imagined to have been principally (but not exclusively)
arboreal and to have incorporated a significant amount of
bipedalism in posture and locomotion, both in trees and on
the ground
...
The cranium would
have been prognathic (protruding), as is seen in fossil and
living apes
...
African apes, for example,
have thin enamel, a presumed shared derived character
...
If humans and chimpanzees are one
another’s closest relatives, and given that chimpanzees and
gorillas share so many anatomical features, the common
ancestor is likely to have been rather chimplike, says Pilbeam
...
) This proposed pattern would include
a degree of knuckle-walking and thin-enameled teeth
...
The recent discovery of a 4
...
This
species is chimplike in some aspects of its dentition, including
possessing thin enamel, and in its postcranial anatomy
...
For
instance, African apes have four lumbar vertebrae, early
hominins (as seen in two specimens of Australopithecus
africanus and one Homo erectus) have six (presumably as an
adaptation to bipedalism), and modern humans have five
...
Anatomists consider such a
progression as evolutionarily difficult, or at least unparsimonious
...
For instance, experimental modification in the timing of expression of certain genes
that control development (homeobox genes) in mice readily
changes the number of lumbar vertebrae that develop
...
The discovery
of the 6-plus million-year-old Sahelanthropus tchadensis,
announced in 2002, is a case in point
...


Classification of hominoids
The superfamily Hominoidea has traditionally been divided
into three families: Hylobatidae (gibbons and siamangs),
Pongidae (orangutan, gorilla, and chimpanzee), and
Hominidae (humans)
...

Morris Goodman proposed such a revision in the early 1960s,
based on his initial results
...
The Hylobatidae family would remain intact, while
orangutans would represent the sole occupants of Pongidae
...
One argument against it, promulgated successfully by the influential paleontologist George
Gaylord Simpson, notes that placing humans and African
apes in the same family obscures the evolutionary changes
that have occurred in the past 5 million years or so, in which
humans moved to a very different adaptation
...
8) A distinct ape grade exists, Simpson argued, which differs from the human grade
...
8 Hominoid adaptations:
This diagram by George Gaylord Simpson
expresses his rationale for supporting the
traditional hominoid classification, in which
all the great apes are members of a single
family, the Pongidae
...


15: Ape and Human Relations: Morphological and Molecular Views
table 15
...
B is an alternative proposed by
Mann and Weiss
...
(But see text for a later
modification
...
) To change
the hominoid classification would not only discard this grade
distinction, it is said, but also cause confusion
...
After all, a grade is an artificial construct of the
human mind, having no fundamental biological basis
...
The second point is correct: there is confusion over
terminology
...

Now, some see it as including humans and African apes; to
others, it means humans, African apes, and orangutans; and
to still others, it signifies humans, African apes, orangutans,
and Asian lesser apes
...
1 for some examples)
...
For instance, in Goodman’s classification, the family
Hominidae includes humans and all apes; at the lowest
level of the classification, the subtribe, gorillas belong to
the Gorillina but human and chimpanzee species share the
Hominina
...
Others suggest that this
classification is too inclusive, although it does reflect the
close evolutionary relationship of humans and chimpanzees
...
A still less
inclusive classification might give humans, chimpanzees,
and gorillas their own subfamiliesaHomininae, Paninae, and
Gorillinae, respectively
...
For instance,
humans would be called hominins under the latter scheme,
which is the chosen route in this book
...
Does it continue to
influence current thought?
• Why are the shared adaptations to knuckle-walking in African
apes unlikely to be homoplasies?
• How can local molecular clocks for the Hominoidea be tested for
accuracy?
• If, as some believe, the evolutionary tree for the African hominoids remains unresolved, what further data would clarify this
uncertainty?

KEY REFERENCES
Andrews P
...
Nature
1992;360:641–646
...
Cladistic relationships of extant and fossil
hominoid primates
...

Bailey W
...
Evol
Anthropol 1993;2:100–108
...
Relations among the great apes and humans
...

Burke AC, et al
...
Development 1995;12:333–346
...
Genetic differences between humans and apes
...

Goodman M
...

Mol Phylogen Evol 1996;5:269–285
...
Testing hominoid phylogeny with the
PHYLIP programs
...


102

Part Four: Hominin Beginnings

Kim H-S, Takenaka O
...
Am J Physical Anthropol 1996;100:301–309
...
Rates of nucleotide substitution in primates and
rodents and the generation-time hypothesis
...

Mann A, Weiss M
...

Mol Phylogen Evol 1996;5:169–181
...
Learning to live with a trichotomy
...

Moore WS
...
Evolution 1995;49:718–
726
...
Genetic and morphological records of the Hominoidea
and hominid origins: a synthesis
...


Rogers J
...
J Human Evol 1993;25:201–215
...
Molecular evolutionary processes and conflicting gene
trees: the hominoid case
...

———
...
Am J Physical Anthropol
1995;98:218–232
...
Molecular phylogeny of the hominoids
...

Shoshani J, et al
...
Mol Phylogen Evol 1996;5:102–154
...
A genetic perspective on the origin and history of
humans
...

Wildman DE, et al
...
4% nonsynonymous DNA identity between humans and
chimpanzees: Enlarging genus Homo
...


ORIGIN OF THE
HOMINOIDEA

16

Anthropoids (monkeys and apes) appear to have evolved some 50 million years ago, in Africa
...
Around 18 million years ago,
an African hominoid species migrated into Asia and underwent
an adaptive radiation
...


The Hominoidea (apes and humans) is one of two superfamilies that constitute the infraorder Catarrhini; the second
superfamily is the Cercopithecoidea (Old World monkeys)
...
This unit will
describe current thinking about the evolutionary history
of anthropoids, and particularly the hominoids, including
relationships between fossil and living species
...
1)
...
The early fossil record is concentrated in
North Africa and Eurasia, with some specimens found in East
and southern Africa
...
This pattern may reflect real changes in the
history of the group, or it may partly result from a biased fossil
record: forest habitats, such as those in sub-Saharan Africa,
are generally poor environments for fossil preservation
...
Some 15
genera and 65 species of Old World monkey exist, compared
with five genera (Pan, Gorilla, Pongo, Hylobates, and Homo)
and two dozen species of hominoid (a dozen of these are
members of the Hylobates group, or gibbons)
...

Third, the early apes were not merely primitive versions of
the species we know today
...
In fact, most fossil
apes are apelike only in their dentition, while much of the
postcranial skeleton was monkeylike
...
1 Features of the catarrhine
fossil record: A major lesson to be inferred
from the main features of the catarrhine
fossil record is that the present is not always
a direct key to the past
...
today

Many novel anatomical and
behavioral adaptations in fossil
species; cf
...
” Such anatomical novelties probably caused the early apes to be behaviorally distinct
as well, as measured in terms of the way they moved and
what they ate
...

If the current fossil record is a reasonable reflection of
catarrhine history, then a number of general trendsain body
size, brain size, and locomotor and dietary adaptationacan
be seen that are common to most groups undergoing adaptive radiation
...
Second, relative brain size is generally
larger among the catarrhines than among the prosimian primates; and ape brains are larger than monkey brains
...
Modes of locomotion come to include
suspensory climbing in trees (apes only) and terrestriality
(apes and monkeys); leaf-eating (folivory) becomes steadily more important within the group as a whole (mainly
monkeys)
...
The most abundant
early fossil evidence of anthropoids is found in North Africa,
at the early Oligocene sites of the Fayum Depression, Egypt,
where specimens range in age from 37 to 31 million years
...
The present fossil evidence strongly indicates an
African origin of hominoids, occurring some 25 million years
ago
...
The middle and later Miocene saw radiations
of at least two groups of ape, one (the most common) in
which the dentition resembles that of living hominoids and
the postcranial skeleton is primitive; and the other in which
the dentition is primitive and the postcranium more apelike
...


Early anthropoids
Algeripithecus minutus, a small primate that lived in North
Africa perhaps as long as 50 million years ago (early Eocene),
holds uncertain claim to be the earliest known anthropoid
...
A little younger is the
newly named Chinese genus Eosimias (dawn ape)
...
Eosimias also
possesses some dental characteristics of living hominoids but
is prosimian in all other respects
...
The presence of
other Eocene anthropoid species, Amphipithecus and Pondaungia, in Burma is taken by some to imply an Asiananot
Africanaorigin of anthropoids
...

Currently one of the driest places on Earth, the region was
covered with tropical forest bordering an inland sea 35 million years ago
...
Simons and his colleagues
have recovered fossils of 11 anthropoid species, from beds
dated at 37 to 31 million years ago
...

Parapithecids, which include Qatrania, Serapia, Algeripithecus, and Apidium, were small, marmoset-sized anthropoids
that were mostly leaf-eaters
...
They also possessed the New World monkey dental formula: two incisors, one canine, three premolars, and three molars on each side of the upper and lower
jaws
...
) The New World dental structure may therefore have
been primitive for all anthropoids
...

The Propliopithecidae includes Propliopithecus, Catopithecus,
and Aegyptopithecus, the largest of the Fayum anthropoids
(males weigh as much as 13 pounds)
...

Males were significantly larger than females in this group,
implying social systems in which males competed for females
in some kind of polygynous structure (see unit 13)
...
The origin of this group (and
the parapithecids) cannot be directly linked with known
earlier Eocene primates, however
...

Aegyptopithecus, or something like it, may therefore represent the form ancestral to Old World monkeys and apes
...
According to Simons, Aegyptopithecus was “a generalized arboreal quadruped” with “no
evidence whatever
...
”

The earliest hominoids
Hominoid fossils are known throughout much of the Miocene
in Africa and Eurasia, with the earliest specimens of a species

16: Origin of the Hominoidea

KNM-RU 2036

Figure 16
...
This individual, a young female that lived approximately
18 million years ago, has characteristics of both modern monkeys
(in its long trunk and arm and hand bones) and modern apes (in its
shoulder, elbow, cranial, and dental characteristics)
...
)

of Proconsul (dated at approximately 22 million years) coming from Africa, the likely region of origin for the clade
...
In any case, the hominoid clade apparently originated
some time between 31 and 22 million years ago
...
3 Miocene apes: These faces of African apes,
which lived some 18 million years ago, illustrate the diversity of
morphology among Miocene apes
...
)

105

Hominoids underwent several adaptive radiations, producing a great abundance and variety of species that followed
lifestyles not typical of modern apes (see figures 16
...
3)
...

Miocene hominoids were creatures of tropical and subtropical forests
...
Cercopithecoid diversity increased in parallel with this change,
and many monkey species came to occupy niches previously
filled by hominoids
...

Most Miocene apes more closely resemble monkeys in terms
of their posture and locomotion
...
(See figure 16
...
)
Proconsul fossils have been found at several sites in Kenya,
and this species is probably the best-known Miocene ape
...
The brain was relatively large,
and the increased surface area of the molars and broadening
of the incisors imply a more frugivorous diet
...
For instance, although it had no tail (like an ape),
its thorax was narrow and deep, a characteristic seen in
pronograde (body horizontal to the ground) monkeylike
locomotion rather than orthograde (body more vertical to
the ground) apelike locomotion
...

In the hindlimb the reverse is true: the foot and lower leg
bones are very apelike while the hip region looks less so
...
Interestingly, the hand had a large, opposable thumb,
which makes Proconsul more like humans than either monkeys or apes
...
4 Rusinga Island in the early Miocene: This
community of apes, living 18 million years ago, illustrates
something of the species diversity that would later become the
characteristic of monkeys
...
(Courtesy of John Fleagle/Academic Press
...


Later hominoids
The earliest hominoid species have (so far) been recovered
from African sites, indicating an African origin of the clade
...
(See
figure 16
...
) In Europe, the earliest species is Dryopithecus,
which enjoyed a widespread radiation and dated from the
same time period
...
The presence of Miocene hominoids in Eurasia

5 cm

Figure 16
...

The animal was roughly the same size as a chimpanzee but had the
facial morphology of an orangutan; it ate soft fruit (detected in the
toothwear pattern) and was probably mainly arboreal
...
)

reflects faunal migrations (and subsequent adaptive radiations) from Africa after the continents joined through tectonic
action, 18 million years ago
...
)
Hominoids later than Proconsul may be divided into archaic
forms (hominoid dentition; primitive postcranium) and
modern forms (primitive dentition; hominoid postcranium)
...

Some of the principal Miocene hominoids will now be
described in these terms
...
Afropithecus, from
northern Kenya, and Heliopithecus, from Saudi Arabia, are
slightly younger than Proconsul but very similar to it in
many ways
...
Thick enamel
on cheek teeth probably represents an adaptation to a
diet containing hard food items, such as tough fruits
...
For instance, Kenyapithecus (an archaic
Kenyan species that lived from 12 million years ago) and
Dryopithecus (a modern form that lived between 13 and 8 million years ago) have thick and thin enamel, respectively
...
Until that time two species of Kenyapithecus
had been recognized, the 15-million-year-old K
...
wickeri
...
The Baringo fossil closely resembles
K
...
africanus
...

wickeri as a stronger contender for ancestry of hominoids
...

Other archaic hominoids include Ouranopithecus (Greece),
Lufengpithecus (China), Sivapithecus, the recently discovered
Otavipithecus (a Namibian species from 15 million years ago),
and Ankarapithecus (a Turkish species, dated at 9
...
The first two lived approximately 8 million years ago
...
Ankarapithecus,
details of which were published late in 1996, exhibited a
mix of gorillalike and orangutanlike features in its cranial
anatomy
...
6 to 0
...
It had large, thickly enameled molar teeth, stood as
high as 8 feet tall, and weighed as much as 640 to 650
pounds, making it the biggest hominoid ever
...
This relationship is based on anatomical similarities in the structure of the face and palate
...

They include Oreopithecus (from Italy), Morotopithecus bishopi
(from Uganda), and Dryopithecus
...
Its dentition represents a mix of primitive and
derived characters (but not like those of living hominoids);
its trunk was short and the thorax broad, with long arms and
short legs
...

Its evolutionary relationships are unknown
...


107

The Ugandan fossil, first found in the 1960s and recently
dated to at least 20
...

Parts of its postcranial anatomy, including shoulder and lumbar vertebrae, were derived in the direction of living apes and
humans
...

Dryopithecus specimens have been found in Spain, Greece,
Germany, and Hungary
...

Dryopithecus has been subject to many different phylogenetic
interpretations since its discovery
...
The newly discovered postcranial material is interpreted
as reflecting more suspensory adaptation and orthograde
posture (similar to living apes) than are seen in any Miocene
ape
...
The ratio
of arm length to leg length (intermembral index) is larger
than in living African apes and similar to that in the
orangutan
...
5 million years,
indicating that the postcranial adaptations of living apes
might have evolved by that date, depending on the still
unsettled evolutionary relationship between Dryopithecus
and the living apes
...
Undoubtedly, the hominoid radiation
was diverse and successful, and the later fossil species lived
in drier, more open woodland habitats than either living
hominoids or the early Miocene species
...
Today’s African apes are
woodland and forest creatures, while early hominins lived in
more open environments
...

A recent study of fossil anatomy and of DNA from living
anthropoids has led to a novel scenario for the history of the
group
...
It underwent a rapid adaptive radiation, giving rise to

108

Part Four: Hominin Beginnings

the ancestors of the orangutan and the gibbons
...
Some anthropologists contend that the
evidence is not clear enough to back such a scenario
...

• Once abundant and diverse, hominoids were reduced to just a
few genera
...
Paleoecology and hominoid paleoenvironments
...

Andrews P, Pilbeam D
...
Nature
1996;379:123–124
...
Earliest complete dentition of an anthropoid primate
from the late Middle Eocene of Shanxi Province, China
...

Begun D
...
Yearbook
Physical Anthropol 1994;37:11– 64
...
Middle Miocene hominoid origins
...


de Bonis L, Koufos GD
...
Evol Anthropol 1994;3:75–83
...
Diamonds in the desert: the discovery of Otapithecus
namibiensis
...

Gebo DL, et al
...

Science 1997;276:401–404
...
The oldest Eurasian hominoid
...

Köhler M, Moyà-Solà S
...
Proc Natl Acad Sci
USA 1997;94:11747–11750
...
Rudábanya: A late Miocene subtropical swamp
deposit with evidence of the origin of African apes and humans
...

Moyà-Solà S, Köhler M
...
Nature 1996;379:156–159
...
Genetic and morphological records of the Hominoidea
and hominid origins
...

———
...
Proc Natl Acad Sci USA
2000;97:10684–10686
...
Functional and phylogenetic features of the forelimb in
Miocene hominoids
...
, eds
...
New York:
Plenum, 1996
...
Paranasal sinus anatomy of Aegyptopithecus: Implications for hominoid origins
...

Simons EL, Rasmussen T
...
Evol Anthropol 1994;3:128–139
...
Primate evolution—in and out of Africa
...
(See also correspondence, Curr Biol
1998;8:R745–R748; Curr Biol 1998;9:119–122; Curr Biol 1998;9:547–
550
...
Equatorius: a new hominoid genus from the middle
Miocene of Kenya
...


ORIGIN OF
BIPEDALISM

17

Upright walking (bipedalism) is the adaptation that defines
hominins, and preceded the origin of tool use and enlarged brains by
at least 2 million years
...


Although Homo sapiens is not the only primate to walk on two
feetafor instance, chimpanzees, a small species of orangutan,
and gibbons often use this form of posture in certain environmental circumstancesano other primate does so habitually
or with a striding gait
...
As a result, anthropologists have often
sought “special”athat is, essentially humanaexplanations
for the origin of bipedalism
...

Human evolution is often cast in terms of four major novelties: upright walking, reduction of anterior teeth and
enlargement of cheek teeth, elaboration of material culture,
and a significant increase in brain size
...
In
other words, hominins show a pattern of mosaic evolution
...
5 million years ago (see unit 23)
...
It is therefore possible that the first hominin might have been apelike
in all respects, apart from an adaptation to upright walking
...

In this unit we will examine some of the mechanics of

bipedalism, the ecological context in which it might have
arisen, and the development of hypotheses that purport to
account for its evolution
...
The leg in the swing phase pushes off using the power
of the great toe, swings under the body in a slightly flexed
position, and finally becomes extended as the foot again
makes contact with the ground, first with the heel (the heelstrike)
...
(See figure 17
...
)
Three key features differentiate human and chimpanzee
bipedalism
...

Thus, muscular power must be exerted in order to support
the body
...
The human knee can be “locked” into the
extended position during the stance phase, thereby minimizing the amount of muscular power needed to support the
body
...

Second, during each swing phase the center of gravity of
the body must be shifted toward the supporting leg (otherwise one would fall over sideways)
...
In humans,
because of the inward-sloping angle of the thigh to the knee
(the valgus angle), the two feet at rest are normally placed
very close to the midline of the body
...

Third, the transverse and longitudinal arches of the human
foot make it a propulsion-contributing lever, as compared
with the grasping function of the chimpanzee foot
...
As we shall see later, these differences
have implications for energetic efficiency
...
(See figures 17
...
6
...
1 Phases of bipedalism:
Upright walking in humans requires a fluid
alternation between stance phase and swing
phase activity for each leg
...


Pelvis tilts
Gluteus medius
and minimus

Ecological context of the origin
of bipedalism
The nature of the evolution of bipedalism in hominins
depended, of course, on the nature of the locomotor adaptation of the immediate ancestor
...
In any case, the quadrupedal
to bipedal transformation is not as dramatic a shift as it might
at first appear, because primates are not true quadrupeds
(like a horse), and body posture is often relatively upright,
such as in tree-climbing
...


Figure 17
...
They contract
on the side in the stance phase, preventing a collapse toward the
side of the unsupported limb
...
(Courtesy of David Pilbeam
...
In the 1960s, this
incipient “Man the Hunter” scenario found an added advant-

17: Origin of Bipedalism

Lumbar curve

Short, broad ilium

Short ischium

Large head of femur

Relatively long hindlimbs

Adducted knee

Short toes

Adducted great toe

Figure 17
...
These characters bring the knees
closer to the center of the body (adduction) to form the valgus angle
of the femur, and bring the great toe in line with the other toes
(adduction)
...

Recently, with the replacement of the “Man the Hunter” image

111

by “Man the Scavenger” (see unit 26), it has been suggested
that the endurance locomotion provided by bipedalism
enabled the earliest hominins to follow in the wake of migrating herds, opportunistically scavenging the carcasses of the
inexperienced young and the infirm old
...
7
...
5
million years, but also no indication of regular meat-eating
has been found in the dentition of the earliest known
hominins
...
8
million years agoathat is, until the origin of Homo erectus
...

The last explanation has been featured in two hypotheses in
recent years: the “Woman the Gatherer” hypothesis, and the
“Man the Provisioner” model
...
As often happens in modern chimpanzees,
females are envisaged as having foraged together and with
their offspring, with whom they shared food
...
The “Woman the Gatherer”
hypothesis is more conservative than the “Man the Hunter”
model, in that the first hominins are viewed as being basically apelike rather than already essentially human
...

Another hypothesis that focuses on the need to carry
things is “Man the Provisioner,” in which males gathered
food and returned it to some kind of home base; there, the
food was shared with females and offspring, specifically “his”
female and offspring
...
Such a provisioning pattern would enable females to reproduce at shorter
intervals, thus giving them a selective advantage over other
large hominoids, which, says Lovejoy, were reproducing at a
dangerously slow rate
...
Although it received widespread attention, Lovejoy’s
hypothesis has been widely criticized, not least because the

112

Part Four: Hominin Beginnings
Chimpanzee

Human

Figure 17
...


Human knee

Afarensis knee

very large degree of sexual dimorphism in body size seen in
these creatures is very difficult to explain, given the putative
monogamous social structure proposed (see units 12 and 13)
...
5 The valgus angles in
humans, apes, and an early hominin:
The angle subtended by the femur at the
knee, the valgus angle, is critical to bipedal
locomotion
...
An ape’s
femur is not angled in this way, causing
the animal to “waddle” during bipedal
locomotion
...

Also note the humanlike shape of the A
...
(Courtesy of Luba Gudz
...
Very simply, they suggest that
bipedalism might have evolved, not as part of a change in the
nature of the diet or social structure, but merely as a result of
a change in the distribution of existing dietary resources
...
In this scenario, the evolution

17: Origin of Bipedalism

113

Occipital
condyle

Figure 17
...
The
occipital condyles articulate with the first
vertebra (atlas vertebra) of the axial spine
...
7 Hypothesized causes
of bipedalism: Perhaps the defining
characteristic of hominins, bipedalism has
inevitably long been the focus of speculation
as to its evolutionary cause
...


Provisioning offspring

Freeing the hands

Predator avoidance

Tracking migrating herds

of bipedalism reflects the improved locomotor efficiency
associated with foraging, and nothing else
...
)
Rodman and McHenry’s proposal is based on a few simple
points
...
Second,
chimpanzees are roughly 50 percent less energy-efficient
than conventional quadrupeds when walking on the ground,
whether they employ knuckle-walking or move bipedally
...
” (See figure 17
...
)
For bipedalism to evolve among hominoids, only a selective advantage favoring improved energetic efficiency of
locomotion was necessary
...

Rodman and McHenry’s hypothesis has recently been
challenged on several counts, particularly by Karen Steudel

of the University of Wisconsin
...
In addition, the postcranial
skeleton of the early hominins differed from that of modern
humans, specifically in including a significant degree of arboreal adaptation
...
There is, concludes Steudel, “no
reason to suppose that our quadrupedally-adapted ancestors
would have reaped energetic advantages when they shifted
to an upright stance
...
The skeletal remains of Australopithecus afarensis have been widely interpreted to imply a bent
knee, bent hip (BKBH) mode of gait, as opposed to the striding gait of modern humans
...
0
2
...
8
2
...
6

Chimp walking

2
...
4

Human running

2
...
2

Human walking

2
...
25 ms–1
Running @ 3
...
0
–0
...
0

0
...
5

2
...
5

Log body mass (kg)

Figure 17
...
83 meters per second)
in mammals of different body size; the dotted line shows the cost of
walking (at 1
...
Note that chimpanzees are less
efficient than other mammalian quadrupeds at both running and
walking, while humans are less efficient at running but more
efficient at walking
...
In computer simulations and treadmill measurements,
Crompton and his colleagues show that oxygen consumption
increases by 20 percent, and core body temperature rises
almost 2°C after 15 minutes of BKBH locomotion
...
” Jack Stern, of the
State University of New York, challenged the conclusion, and

Bipedal

X′

Miocene
drying

Daily travel distance

y

ilit

ab

rc

ou

w
Lo

Quadrupedal

il
va
ea

s
re

Pan

X
ity

abil

vail
ce a
our

s
h re

Hig

Group size

Homo

pointed out that even BKBH locomotion would be effective
for moving between dispersed food sources, if not for longdistance journeys
...

Lynne Isbell, of Rutgers University, and Truman Young, of
Fordham University, recently extended the evolutionary
context of the energy-efficiency hypothesis to other African
hominoids
...
Isbell and Young accept
that bipedalism represents one potential adaptation to this
situation, which inevitably requires an increase in the daily
travel distance while foraging for dispersed resources
...
(A large group
requires more total food resources each day than a small
group, and must therefore travel further to harvest it
...
As
part of their argument, they cite field observations of gorillas
and chimpanzees in Gabon, where the apes feed heavily
on fruits
...
In contrast, chimpanzees continue to eat fruits, but
forage in smaller groups or even alone
...
9
...
A key issue, of course, is what exactly were
the environmental conditions when bipedalism originated,
not what they were when the new mode of locomotion was
well developed
...
9 Alternative adaptations:
The solid lines depict the relationship
between daily distance traveled and group
size under conditions of low resource
availability (upper line) and high availability
(lower line)
...
A shift from high to low
resource availability occurred during the
late Miocene
...

(Adapted from Isbell and Young
...
From more than 600 hours of field observations of
chimpanzees and their bipedal behaviorawhich included
stationary feeding of fruits from bushes and low branches in
small trees, and locomotion from one spot to anotheraHunt
made the following observations: 80 percent of bipedal
behavior was related to stationary feeding; only 4 percent
was observed during direct locomotion
...

The plethora of hypotheses offered to explain the evolution of bipedalism reflects both a fertility of ideas among
anthropologists and the difficulty of using available evidence
to discriminate between them
...


KEY QUESTIONS
• What does the rarity of primate bipedalism imply, other than that
it is “difficult” to evolve?
• Given the energetic differences between hominoid quadrupedalism and human bipedalism, would an evolutionary transformation
be necessarily fast or slow?
• Which hypotheses would suffer adversely if bipedalism evolved in
a wooded or even forested context?
• Could a hominoid that was completely apelike apart from being
bipedal be classified as a hominin?

115

KEY REFERENCES
Crompton RH, et al
...
J
Human Evol 1998;35:55–74
...
The evolution of human bipedality: ecology and functional
morphology
...

Isbell LA, Young TP
...
J Human Evol 1996;30:389–
397
...
Evolution of human walking
...

Richmond BG, Strait DS
...
Nature 2000;404:382–385
...
Bioenergetics of hominid bipedalism
...

Sellers WI
...
J Exp Biol 2003;206:1127–1136
...
Sunset on the savannah
...

Stern JT, Jr
...
J Human
Evol 1999;36:567–570
...
Limb morphology, bipedal gait, and the energetics of
hominid locomotion
...

Wang WJ, et al
...
J Human Evol 2003;44:561–577
...
In hominoids there was an evolutionary trend
toward shorter jaws and a deeper face, giving a less snout-like aspect
...
Eruption patterns give insight into a species’ life history
...


Jawsaparticularly lower jawsaand teeth are by far the most
common elements recovered from the fossil record
...

Because jaws usually serve as an animal’s principal foodprocessing machine, the nature of a species’ dentition can
yield important clues about its mode of subsistence and
behavior
...
For instance, human and ape dentition retains
roughly the basic hominoid pattern established more than 20
million years ago
...
Similar sets of
jaws and teeth may therefore arise in species with very different biological repertoires
...


Basic anatomy
Perhaps the most obvious trend in the structure of the primate jaw (and face) throughout evolution is its shortening
from front to back and its deepening from top to bottom,
going from the pointed snout of lemurs to the flat face of
Homo sapiens
...
(See figures
18
...
2
...
Grinding efficiency increases as the distance
between the pivot of the jaw and the tooth row decreases,
with hominins being closest to this position
...
This pattern is seen in
modern-day New World anthropoids, while Old World

Increased brain size
Shorter face
Reduced jaw robusticity
Larger anterior teeth
Smaller cheek teeth

Australopithecus

Homo

Figure 18
...
For
instance, the face became increasingly
shorter throughout hominid evolution,
while robusticity of the jaw first increased
and then decreased
...


18: Jaws and Teeth 117

Chimpanzee

Human

Incisors

Diastema

Canine
Premolars

Molars

Figure 18
...


Chimpanzee

anthropoids possess two premolars (not three), giving them
a total of 32 teeth
...
One of the most striking differences,
however, is that apes’ conical and somewhat blade-shaped
canine teeth are very large and project far beyond the level of
the tooth row; in these animals, males’ canines are substantially larger than those found in females, an aspect of sexual
dimorphism with significant behavioral consequences (see
unit 13)
...
As a result of the canines’
large size, an ape’s jaw is effectively “locked” when closed,
with side-to-side movement being limited
...
As a result,
the tooth rows have no diastemata, and a side-to-side
“milling” motion is possible, which further increases grinding
efficiency
...
2
...
In con-

Modern human

trast, human upper incisors are smaller and more vertical,
and, with the small, relatively flat canines, they form a slicing
row with the lower teeth
...
Ape molar teeth are
larger than the premolars and include high, conical cusps
...
” The molars themselves are
large and relatively flat, with low, rounded cuspsacharacteristics that are extremely exaggerated in some of the earlier
hominins (see unit 20)
...
In some of the earliest known hominins
aArdipithecus ramidus and Australopithecus anamensis from
more than 4 million years ago (see unit 19)athe dentition
remains strikingly apelike, with a significant degree of sexual
dimorphism
...
3 and 18
...
) Within 2 million
years, however, the canines in several hominin species have
become smaller and flattened, looking very much like
incisors (see unit 20)
...
Recently
anthropologists have debated this aspect of hominoid dentition, specifically asking how early hominins fit into this
picture
...

The ape tooth eruption pattern is M1 I1 I2 M2 P3 P4 C M3;
the corresponding human pattern is M1 I1 I2 P3 C P4 M2 M3
...
Associated with the prolonged period of
infancy in humans is an elongation of the time over which
the teeth erupt
...
3, 6
...
5 years in apes, whereas the ages are 6, 12,
and 18 years in humans
...
An ape’s jaw with the first molar just erupted would
indicate an individual a little more than 3 years old
...
3 Early hominin dentition:
The first premolar in apes is characteristic in
having one cusp (protoconid); in humans,
the tooth has two cusps (the protoconid
and metaconid)
...
In
Australopithecus afarensis, an early hominin,
the tooth is intermediate in shape between
humanlike and apelike, but its axis
resembles that seen in apes
...

University of Michigan anthropologist Holly Smith analyzed tooth eruption patterns in a series of fossil hominins
and concluded that most of the early species were distinctly
apelike
...
9 million until
approximately 400,000 years ago, her results implied that
early members of this species showed a pattern that was
intermediate between humanlike and apelike
...
The individual was a youth whose
second molar was in the process of erupting
...
In
fact, Smith’s analysis suggests that he was probably 9 years
old
...

Smith’s conclusion has been challenged by University
of Pennsylvania anthropologist Alan Mann, who a decade
earlier had proposed that all hominins followed the human

18: Jaws and Teeth 119
(b)
(a)
Small gap in
front of canine

Ramapithecus

Chimpanzee

Long muzzle
Projecting incisors
Gap in
front of canine

Fairly large canines,
worn down at sides

(c)

Large canines, worn
down at sides

Australopithecus

(d)

Long muzzle

Figure 18
...
(From Our Fossils
Ourselves, courtesy of the British Museum
[Natural History]
...
Nevertheless, Smith’s position
received support in late 1987, when Glenn Conroy and
Michael Vannier of Washington University School of Medicine published results of their computed tomography (CT)
analysis of the Taung child’s skull
...

The debate has been extended further by two researchers
at University College London, who claim to be able to determine the exact age of a tooth by counting the number of lines
astriae of Retziusawithin the enamel
...

When Bromage and Dean applied their technique to a
series of australopithecine and early Homo fossils, they
obtained ages that were between one-half and two-thirds
of what would be inferred if a human standard of dental
development had been applied
...
This insight implies that infant care in these early
hominins followed the ape pattern
...
As a result, social life becomes greatly
intensified
...


Small canines, worn
down at tips

Enamel thickness
The relative thickness of enamel on cheek teeth has played
an important role in anthropology, not least because Elwyn
Simons interpreted Ramapithecus as being an early hominin
through identification of this character
...
Until the 1994 discovery of
Ardipithecus ramidus changed the picture, all known fossil
hominins also possessed thick enamel
...
Thin enamel was seen as an adaptation to
fruit-eating, while thick enamel was envisioned as an adaptive response to processing tougher plant foods
...
Thin enamel appears to be a primitive character for
the hominoid clade as a whole, but thick enamel has arisen
several times independently during the history of the group
...
The most
recent analysis of enamel formation in hominoids and a
re-evaluation of late Miocene hominoids in Africa have
turned this view around, however
...
The thick

120

Part Four: Hominin Beginnings

enamel of later hominins and, for instance, the late Miocene
ape Sivapithecus reflects independent evolution, not homology
...
Using a scanning electron microscope, Alan Walker of Pennsylvania State University has produced images of a range of characteristic toothwear patterns:
for grazers, browsers, frugivores, bone-crunching carnivores,
and so on
...
In a
series of comparisons, all early hominins appear to fit into the
frugivore category, along with modern chimpanzees and
orangutans
...

A major shift occurs, however, with Homo erectus, whose
enamel is heavily pitted and scratched
...
Although it is not yet possible
to interpret precisely the implications for the Homo erectus
diet, it is significant that toothwear patterns indicate some
sort of abrupt change in hominin activities at this point in
historyaperhaps significant brain expansion, reduction in
body size dimorphism, systematic tool making, use of fire, or
migration out of Africa
...


KEY QUESTIONS
• How reliable are teeth as indicators of a species’ diet?
• What other information would one need to assess the significance of the reduction of overall size and loss of sexual dimorphism
in hominin canines?
• How would you recognize the jaws and teeth of the first hominins?
• How reliable a phylogenetic indicator is enamel thickness?

KEY REFERENCES
Beynon AD, et al
...
Am J
Physical Anthropol 1991;86:295–309
...
Re-evaluation of the age at death of immature fossil hominids
...

Conroy GC, Vannier MW
...
Nature 1987;329:625–627
...
Role of time and timing in hominid dental
evolution
...

Mann AE, et al
...
Nature
1987;328:673–675
...
Dental development in Australopithecus and early Homo
...

———
...
In: Walker A,
Leakey R, eds
...
Cambridge, MA: Harvard University Press, 1993:195–220
...
Dental microwear and dental function
...

Ungar PS, Grine FE
...
J Human Evol 1991;20:313–340
...
Inferences from quantitative analysis of dental
microwear
...


19

THE EARLIEST
HOMININS: A
HISTORY OF
DISCOVERIES

The first early hominin fossil was unearthed eight decades ago
...
Anthropologists’ view of when, where,
and how humans evolved was once relatively simple
...
The once popular notion
that hominins arose in open terrain, even savannah, is no longer
valid
...


In 1925 Raymond Dart published the description of what he
claimed to be a fossilized cranium of an early human ancestor
...

The specimen was said to be in the wrong place (Africa, not
Asia), and it was clearly an ape, not a human, in appearance
...

In 2002, three-quarters of a century after Dart’s discovery,
the announcement of another single cranium has again
grabbed the attention of the anthropological establishment
...
However, despite
some publicly aired reservations, the skull is being acknowledged as “one of the most important finds in the last 100
years,” and it is forcing a transformation of ideas on human
prehistory of a magnitude similar to Dart’s find
...

And the overall picture of human prehistory has changed
dramatically, going from one of great simplicity (essentially a
ladder ascended by a single species at any one time) to one of
much more complexity (essentially an evolutionary bush

with many twigs that have nothing to do with our direct
ancestry)
...
This unit will
describe some of the major discoveries of the past threequarters of a century, and will discuss some of the unfolding
notions about the shape of our past
...
And the prevailing sentiment was that Asia was the cradle of humankind
...

Dart was an Australian anatomist working at the University of the Witwatersrand, Johannesburg, South Africa,
giving him an “outsider” label that the British anthropological establishment also held against him
...
The specimen
consists of the face, part of the cranium, the almost complete
lower jaw, and a brain endocast, formed when sand inside
the skull hardened to rock, recording the shape of the brain
...
Moreover, the canine teeth were smallaalso a humanlike character
...

The remains were those of an immature apelike individual,

122 Part Four: Hominin Beginnings
Dating the South African hominins has proved difficult
because their cave context is not appropriate for radiometric
dating
...
5 to 2
...
0 to 1 million years for the robust species
...
At the caves near Johannesburg,
the habitat was more open
...
Acceptance finally came at the
end of the 1940s
...
At this point, A
...


Major australopithecine discoveries:
East Africa

Figure 19
...
(Courtesy of Peter Kain and Richard
Leakey
...
(See figure 19
...
)
A decade passed before further hominin discoveries were
made, when Robert Broom, a Scottish paleontologist, joined
Dart in Johannesburg and initiated further exploration
...
Sterkfontein and Makapansgat yielded further A
...
robustus, were recovered from Swartkrans
and Kromdraai
...
2
...
)

The first hominin discovery in East Africa was made in mid1959 at Olduvai Gorge in Tanzania, when Mary Leakey
found a cranium (but no lower jaw) that was similar to the
robust australopithecines of South Africa, but even more
heavily built
...
This was later changed to Australopithecus boisei in
recognition that it was a member of the australopithecine
clade
...
3
...
75 million years via the first
application of radiometric dating (potassium/argon) in
paleoanthropology
...
erectus, unit 24), no
unequivocal remains of A
...

Louis Leakey disliked the notion that australopithecines
were part of the direct lineage to Homo
...

The Leakeys’ work at Olduvai Gorge helped establish East
Africa as an important source of early hominins, and the
presence of volcanic ash greatly facilitated establishing an age
for the fossils
...
In his first full season of prospecting on the east
side of Lake Turkana in northern Kenya in 1969, Richard
Leakey found a complete, intact skull of A
...
4)
...
3 “Zinjanthropus”: Shown here with a reconstructed
mandible; the cranium was reconstructed from a jigsaw of hundreds
of fragments
...
)

(b)

Figure 19
...
(b) The gracile form,
from Sterkfontein
...
)

rupted period of discovery, which continues today under
the direction of Leakey’s wife, Meave
...
It is
now in the type specimen of Homo rudolfensis
...
)
Since the early 1980s, collections have also been made on
the west side of Lake Turkana
...
6 million-year-old robust australopithecine, which some term Australopithecus aethiopicus
...
Because
the sediments around Lake Turkana are interleaved with
volcanic tuffs, the fossils of the region can now be securely
dated
...
africanus
...
robustus and A
...

Important discoveries of a new species of Australopithecus,
A
...
These included the famous partial skeleton known
as Lucy (see figure 19
...
Australopithecus afarensis was the
oldest known hominin, at 3-plus million years, and was held
by many as the stem hominin, ancestral to Homo, perhaps
via A
...
Again, the evolutionary scenario is rather
simple, and the temporal distance between afarensis at a little
over 3 million years and the putative origin of the hominin
clade at 5 to 7 million years (from molecular data) should

124

Part Four: Hominin Beginnings
Recent fossil discoveries

Figure 19
...
(Courtesy of Peter Kain and Richard Leakey
...
The plethora of discoveries in the 1990s and
beyond shows that to be the case, and that East Africa was
not necessarily the home of the first hominins, as had been
widely assumed
...
(See figure 19
...
) Most of them are
older than Australopithecus afarensis, and several come from
outside of East Africa
...
5 million years), Australopithecus anamensis (Kenya, 4
...
9 million years), Australopithecus bahrelghazali (Chad, 3 to
3
...
7), Australopithecus garhi
(Ethiopia, 2
...
5 million years),
the specimen mentioned at the opening of this unit,
Sahelanthropus tchadensis (Chad, 6 to 7 million years), and
lastly, announced in March 2004, Ardipithecus Kadabba, represented mainly by teeth, and suggested as an ancestor of A
...
5 to 5
...
Clearly, a good
deal of rethinking is needed about where the hominin clade
arose, and the shape of the evolutionary tree
...
modernhumanorigins
...
)
The discoveries of Ardipithecus ramidus (1994) and Australopithecus anamensis (1995) simultaneously dislodged afarensis
as the earliest known hominin species and threw doubt on
its status as the ancestor of all later hominins
...
The A
...
The dentition is more primitive (that is, more apelike)

Figure 19
...
Her anatomy
combines ape and human characteristics
...
(Courtesy of the Cleveland
Museum of Natural History
...
afarensis

Middle Awash, Ethiopia
A
...
afarensis, A
...
tugenensis

Laetoli, Tanzania
A
...
tchadensis

Figure 19
...


than in afarensis, with narrower molar teeth capped with thin
enamel, unlike the condition in all other known hominins;
the canines are larger, but not as large as in living apes
...

Nevertheless, the position of the foramen magnum, through
which the spinal cord passes in the basicranium, suggests that
the creature may have employed some sort of bipedal
posture
...
The fossils (nine from Kanapoi and 12
from Allia Bay) include upper and lower jaws, cranial fragments, and the upper and lower parts of a leg bone (tibia)
...
The
tibia implies that anamensis was larger than ramidus and
afarensis, with an estimated weight of 46 to 55 kilograms; its
humanlike anatomy implies that anamensis was bipedal in
posture and locomotion
...
2 million years and those at Allia Bay at 3
...

Because the history of australopithecine discoveries was,
until recently, located exclusively in eastern or southern
Africa, many anthropologists assumed that it reflected a real
difference in the distribution of hominins and apes
...
The relatively continuous forest cover of central and western Africa
was thought to provide an unsuitable habitat for hominins
...
africanus

At the end of 1995, however, this picture changed, with the
announcement of the discovery of a hominin mandible in
Chad, central Africa, which is 2500 kilometers west of the
Rift Valley
...
5
million years old
...
On further study, however, they identified differences that signaled a different
species, which they named Australopithecus bahrelghazali
...
Some scholars,
such as White, have suggested an ancestor–descendant relationship, with ramidus being ancestral to anamensis, and anamensis being ancestral to afarensis
...

The discovery of bahrelghazali further complicates the picture
...

Because it is more gracile than other hominins of the time,
the authors say, this species may be related to the ancestry
of Homo
...

The 2001 announcement of Kenyanthropus platyops was
significant for several reasons
...
Second, K
...
afarensis (platyops
means “flat face”), a feature of hominins that was thought to
have evolved much later in human prehistory
...
5 million years ago was more
diverse than had been assumed
...
The cranium is rather
apelike, especially the prominent brow ridges, while the face
is much more humanlike, being quite flat, unlike in australopithecines
...

With an age of between 6 and 7 million years (based on
faunal correlation; see unit 7), it is very close to the split
between hominins and African apes
...
But this particular combination was quite
unexpected, because the flat face is characteristic of hominins
one-third its geological age, in Homo habilis, for example
...
Such evolutionary reversals
are viewed as unlikely
...
7 Australopithecus bahrelghazali: This newly
discovered partial mandible from Chad, central Africa, is the first
australopithecine to be found west of the Rift Valley, overturning
the assumption that hominin habitat was restricted to areas east of
the Rift Valley
...
(Courtesy of M
...
)

afarensis being ancestral to all later hominins is likely to oversimplify hominin evolution
...
Unearthed
in Ethiopia, it consists of parts of the cranium, upper jaw,
and a few limb bones
...
But the teeth are
much larger, which formed part of the reason that the discoverers, Berhane Asfaw and Tim White, believe a new
species is warranted
...
The first is a “linear” model, favored, for
instance, by Asfaw and White
...
The linear model argues that distinctive hominin anatomy evolved only once, followed by a ladderlike ancestor–
descendant series
...
The bushy model, by contrast, holds that hominin evolutionary history has been a series of adaptive radiations,
producing combinations of anatomies in different species
that are still little understood
...

A key lesson of the tchadensis discovery is that a lack of
evidence shouldn’t be taken to imply that evidence doesn’t
exist
...


EARLY HOMININ ENVIRONMENTS
Analysis of the geology of the Aramis site, from which A
...
For
instance, 30 percent of the vertebrate fossils at the site were
colobine monkeys, which are forest animals
...
The Hadar afarensis
population lived in a woodland or gallery forest habitat,
while Laetoli, in Tanzania, was much more open, possibly
even grassland savannah
...
It
is therefore apparent that the earliest hominins occupied a
diversity of habitats, including closed forest and open terrain
...
This is obviously not the case, and has important implications for assessing competing hypotheses for the origin
of bipedalism (see unit 17)
...
afarensis in particular?
• What are the implications of the discovery that the earliest
known hominins lived in heavily wooded or forest environments?

KEY REFERENCES
Andrews P
...
Nature 1995;376:555–556
...
Australopithecus garhi: a new species of early hominid
from Ethiopia
...

Brunet M, et al
...
Nature 2002;418:145–151
...
How reliable are human phylogenetic hypotheses? Proc Natl Acad Sci USA 2000;97:5003–5006
...
Adventures with the missing link
...

Johanson DC, White TD
...
Science 1979;203:321–330
...
New hominin genus from eastern Africa shows diverse
middle Pliocene lineages
...

Lieberman DE
...
Nature
2001;410:419–420
...
Australopithecus ramidus, a new species of early
hominid from Aramis, Ethiopia
...

Wood B
...

Nature 2002;418:133–135
...
Australopithecines were apelike from the neck up and
humanlike from the neck down
...
The anatomy of the pelvis,
legs, and feet has been taken to imply a bent knee, bent hip mode of
bipedalism
...

How many hominin species existed on the continent during
that period remains a matter of debate and uncertaintyano
fewer than six, and maybe more
...
The large-brained species
were members of the genus Homo, of which several species
may have coexisted
...
(See figure 20
...
) (One species, Kenyapithecus
platyops, dated at 2
...
)
Following their acceptance as hominins in the 1940s, australopithecines were considered to be the earliest members
of the hominin clade, with one of them ultimately being
ancestral to early Homo
...
afarensis, it is now clear that
australopithecines were not the earliest hominins; and their

purported ancestry to early Homo is questioned by some
scholars
...
afarensis skeleton
...
In this unit, we will therefore discuss
the anatomy, biology, and behavior of australopithecines;
unit 21 will address the earliest members of the Homo group;
and unit 22 will describe current hypotheses explaining how
these various hominin species were related to one another
atheir evolutionary tree, or phylogeny
...
afarensis is essentially apelike above the neck
and essentially humanlike below the neck (see figures 20
...
3)
...
The cranium
itself is long, low, and distinctly similar to that of an ape,
having a pronounced ridge (the nuchal crest) at the back to
which were attached powerful neck muscles that balanced
the head; the larger individuals (males?) have a sagittal crest
...
afarensis face is small,
while the lower part is large and protruding
...

Many details of the underside of the A
...
The hominin status of
A
...


132

Part Five: The Hominin Adaptation

Chad
A
...
afarensis
Omo, Ethiopia
A
...
boisei, A
...
africanus

Olduvai, Tanzania
A
...
afarensis

Sterkfontein
A
...
africanus

Swartkrans
A
...
robustus

Figure 20
...


A comparison of a modern ape’s dentition (the dentition of
a chimpanzee, for example) with that of modern humans
reveals some striking differences (see unit 18)
...
afarensis is somewhat intermediate between these
two patterns
...
In many individuals, the first premolar is
distinctly apelike in having a single cusp, but the development of a second cusp can sometimes be discerned
...


Figure 20
...
A relatively complete cranium was discovered in
1993, showing anatomy very much like this one
...

(Courtesy of the Cleveland Museum of Natural History
...
The question is, How well does A
...

Owen Lovejoy of Kent State University collaborated with
Johanson and his colleagues to concentrate on the pelvis and

20: The Australopithecines

Figure 20
...
(Courtesy of the Cleveland Museum of
Natural History
...
The pelvis of A
...
These differences were
not functionally significant in terms of achieving the balance
required for bipedal locomotion, concluded Lovejoy
...

In other words, A
...

Meanwhile, other researchers began to see indications
of arboreal adaptation in the A
...
French
researchers Christine Tardieu and Brigitte Senut studied the
lower limb and upper limb, respectively, and inferred a
degree of mobility that would be consistent with arboreality
...
William Jungers reported that although the arms of A
...

Examining certain A
...
(See figure 20
...
)
Following a more wide-ranging survey, Jungers, Jack
Stern, and Randall Susman (all of SUNY, Stony Brook) argued
that the full suite of postcranial anatomical adaptations indicated that, although A
...
Moreover,
they concluded, while the animal was moving on the ground
it could not achieve a full striding gait, as Lovejoy had
argued, but instead adopted a bent knee, bent hip (BKBH)
gait
...
afarensis
...
The selective advantage of a BKBH gait
would therefore have had to have been considerable, given
the energy costs of this form of walking (see unit 17)
...
afarensis locomotor
debate stem partly from a lack of agreement over how to
define the anatomy in certain instances and partly from
differences in functional interpretation of other aspects of
the anatomy
...
Since then, most publications have favored the partially arboreal, BKBH bipedal
locomotor posture
...

Opponents of arboreal adaptation dispute the degree of

134 Part Five: The Hominin Adaptation
Chimpanzee

Human

Curved phalanges
Large pisiform

Cranially oriented
shoulder joint

Australopithecus
afarensis
Funnel-shaped thorax

Long, curved
phalanges
Relatively short
hindlimb

Figure 20
...

(Courtesy of John Fleagle/Academic Press
...
afarensis ankle, and cite the loss of the
opposable great toe, which has become aligned with the
other toes, a clear adaptation to bipedality (but see the discussion below)
...
For
instance, although the forelimbs have assumed hominin proportions, thus improving weight distribution and balance
required for bipedalism, the legs are short, as in an ape
...
In addition, the foot is long
relative to the leg, meaning that clearance could be achieved
only by increasing knee flexion during walking (like trying to
walk in oversized shoes)
...
afarensis to imply a method of
balance during bipedalism more like that of a chimpanzee
than a humanathat is, involving a bent hip
...
afarensis than in modern humans
...
Ergo, this kind of stride does not occur in A
...

Completing the case for a bent knee, bent hip walking
posture is the suggestion by the SUNY researchers that the A
...
The Kent State researchers dispute
three points of this description of the anatomy, ultimately
rejecting the functional interpretation
...
If A
...

Finally, Jungers has examined the size of hindlimb jointsa
particularly the femoral headain modern apes, humans, and
A
...
The rationale was that distributing body weight
on four limbs for most of the timeaas chimpanzees and

20: The Australopithecines
gorillas do, for instanceawould not require the joint surfaces
of the lower limbs to be as extensive, relatively speaking, as
they must be if full weight was permanently balanced on the
hindlimbs, as occurs in humans
...
Although the femoral head surface in
A
...
This finding leads
Jungers to conclude that “the adaptation to terrestrial
bipedalism in early hominins was far from complete and not
functionally equivalent to the modern human condition
...
afarensis should not be too surprising, especially since the
postcranial anatomy of its predecessor, Ardipithecus ramidus,
is reported to be distinctly apelike
...
afarensis is the structure of the
hands
...
For instance, the
thumb is shorter than in the human hand, and the fingertips
are much narrower
...
It should be noted that the earliest
stone tools recognized from the fossil record date to approximately 2
...

Although bipedal in posture, A
...
As can be
seen in figure 20
...
In addition,
as Peter Schmid and Leslie Aiello have demonstrated independently, the shape of the trunk is apelike in being bulky
relative to stature
...
afarensis anatomyaand presumably
behaviorais somewhat intermediate between that of an ape
and a human, a pattern that does not exist today
...
5 Comparison of lower
jaws of Australopithecus robustus and A
...
robustus mandible from Swartkrans
(left) compared with that of A
...
(Courtesy of Milford
Wolpoff
...
africanus and
boisei, respectively, appear to imply substantial anatomical
differences between the two forms, with one being small and
delicately built and the other exhibiting a larger and generally more massive form
...
(See figure 20
...
africanus: 41 kilograms for males and 30 kilograms for
females, with statures of 138 and 115 centimeters, respectively;
• A
...
boisei: 49 kilograms for males and 34 kilograms for
females, with statures of 137 and 124 centimeters, respectively
...
In fact, both were considered to be very
close to 500 cubic centimeters (see unit 31)
...

The teeth, jaw, and cranial anatomy are really one functional complex
...
The two forms of
australopithecine differ in that the robust species have taken

136 Part Five: The Hominin Adaptation
Temporal

Temporal

Zygomatic
arch

Zygomatic arch

Masseter

Masseter
Chimpanzee

Human

Temporal
Zygomatic arch
Masseter
Australopithecus

Figure 20
...
The larger the masseter and
temporal muscles, the larger the arch
...


this adaptation to an extreme, having enormous, flat molars
and relatively small, bladelike incisors and canines
...
For instance,
all hominins have a tooth row that is tucked under the
face more than in apes, giving them a less projecting facial
profile and increasing chewing efficiency
...
The extra
muscle power necessary for this chewing action in the robust
species has two anatomical specializations
...
This sagittal crest, which is also found
in gorillas, is absent in gracile australopithecines
...
This feature and
the strengthening of the central part of the face by pillars of
bone give the robust australopithecine face a characteristic
“dished” appearance
...
6
...
The australopithecine pelvis of 2 million years ago
was very much like that of Lucy, who lived a million years
earlier
...

A partial skeleton of A
...
7 Partial skeleton: Found by Robert Broom and
John Robinson in the late 1940s (and partially reconstructed by
Robinson), these bones clearly show the bipedal anatomy of
Australopithecus africanus (museum number, Sts 14)
...
)

clearly shows a bipedal adaptation (see figure 20
...
And a
recent analysis of an A
...
This implies that this species probably climbed
trees as a significant part of its daily routine
...
8)
...
The shoulders, trunk, and
waist are important elements in human running: the
shoulders enable arm swinging and balance, and in Lucy
these features were more apelike than humanlike
...


Australopithecine biology

1 cm

Figure 20
...
5 million years, this species is
the oldest known hominin in South Africa
...
This feature might have been an
adaptation to a degree of arboreality
...
J
...
)

was not identical to that of a fully committed biped
...
Fred Spoor, an anatomist at
University College London, measured the dimensions of
these three arches (the anterior, posterior, and lateral semicircular canals) in living primates, including humans, and
found an important difference between humans and apes
...
Spoor interprets
the difference in humans as an adaptation to the demands of
bipedal locomotion
...
In all australopithecines, the pattern was
apelike; in contrast, it was humanlike in early Homo
...

An analysis of the trunk of Australopithecus (as seen in
Lucy) implies that, however well adapted this species was for
bipedal walking, bipedal running was not part of its repertoire
...
The hominin
mode of locomotion and dental apparatus are likely to have
been adaptations to a habitataand therefore dietathat
increasingly differed from the environments associated with
apes (see unit 17)
...
Food was probably located in widely scattered
patches and, judging from the structure of these species’
teeth and jaws, appears to have required more grinding than
an ape’s diet
...
robustus indicate that they
did include at least some meat in their diet
...
For instance, using scanning
electron microscopy, Alan Walker found that the microwear
pattern in robust australopithecines resembled that of chimpanzees and orangutans, both of which eat various forms of
fruit
...
The difference, they suggested, matches that found
between the modern-day spider monkey, which eats fleshy
fruits, and the bearded saki, which lives on seeds encased in a
tough covering
...

There is also evidence from the Swartkrans site in South
Africa that the robust australopithecines used “digging sticks”
to probe termite mounds
...
Functionally speaking, this notion is accurate in many
respects
...
Similarly, the mosaic set of
features seen in the A
...


Australopithecus, a tool maker?

Figure 20
...
6 million years
...
(Courtesy of Alan Walker
...
If true, then the fossil record should have revealed
a steady increase through time in dental, facial, and jaw
robusticity
...
The cranium was
as robust as any yet known, but was 2
...

Clearly, the huge molars, flared cheek bones, and dished face
could not be the end-product of an evolutionary line if it
were present at the origin of that supposed line
...

This cranium, known colloquially as the “black skull,” was
surprising not only because of its great age but also because it
contained an unexpected combination of anatomical characteristics (see figure 20
...
Although the face was distinctly
like that of that most robust of robust australopithecines,
Australopithecus boisei, the craniumaparticularly the top and
backawere not: they were similar to those of Australopithecus
afarensis
...

Evidence on this issue is necessarily indirect, such as the
anatomy of the hands
...
africanus have been
discovered
...

By contrast, recent analysis of robust australopithecine hand
bones from the Swartkrans site indicates that they were
much more humanlike
...
According to Susman, the robust australopithecines’ anatomy probably allowed sufficient manipulative
skills to enable stone-tool making, an ability that has usually
been thought of as strictly within the domain of Homo
...
The recently discovered simple bone toolsadigging
sticksamay be taken as support for Susman’s hypothesis
...
Furthermore, some scholars question whether the fossil hand bones
that Susman studied might have been those of Homo and not
A
...

Perhaps the strongest evidence of tool making by an
australopithecine comes from Ethiopia, where Tim White
and his colleagues found the cranial and dental remains of a
hominin they named Australopithecus garhi
...

The researchers point out that stone tools which are the same
age as A
...
No
remains of Homo have been recovered from the area
...
From the cover: evidence of termite
foraging by Swartkrans early hominids
...

Clarke RJ, Tobias PV
...
Science 1995;269:521–524
...
Endocranial capacity in an early hominid cranium
from Sterkfontein, South Africa
...

Crompton RH, et al
...

J Human Evol 1998;35:55–74
...
Evolutionary history of the robust australopithecines
...

Grine FE, Kay RF
...
Nature 1988;333:765–768
...
Environment and behavior of 2
...
Science 1999;284:625– 629
...
How big were early hominids? Evol Anthropol
1992;1:15–20
...
Behavioral implications of early hominid body size
...

———
...
J Human Evol 1998;35:1–22
...
Apelike body proportions in Australopithecus
africanus and their implications for the origin of Homo
...
):163–164
...
Diet of Australopithecus robustus from
Swartkrans
...

Spoor F, et al
...
Evol Anthropol 1996;30:183–187
...
Hand function and tool behavior in early hominids
...

Teaford MF, Ungar PS
...
Proc Natl Acad Sci USA 2000;97:13506–13511
...
2
...
Nature 1986;322:517–522
...
Early hominid species and speciation
...


EARLY HOMO

21

The earliest appearance of a species of Homo seems to be about 2
...
Where once a large collection of specimens from different
localities were designated as Homo habilis, there are now two species
of early Homo recognized, H
...
rudolfensis
...
It is generally assumed
that Homo included more meat in its diet than did species of
Australopithecus
...
1)
...

For the first time, simple stone tools are found in the record
(see unit 23), and diet may have shifted to include more
meat, procured by either scavenging or simple hunting, or
a combination of both (see unit 26)
...
The taxonomic interpretation of early Homo fossils was considered
contentious when they were first found, and in many ways it
remains so today
...
1 Hominin trends: The transition between
Australopithecus and Homo was accompanied by an increase in brain
size and a decrease in the robusticity of the cheek teeth and jaws
...


The first discoveries
The first discoveries of early Homo fossils were made at
Olduvai Gorge, not long after Mary Leakey had found
Zinjanthropus boisei (later known as Australopithecus boisei)
and Louis Leakey pronounced it to be the maker of the
gorge’s stone tools
...

The fossils, which were judged to be slightly older than Zinj
(therefore older than 1
...

Much of the analysis of these fossils was carried out by
John Napier, of London University, and Phillip Tobias, of the
University of the Witwatersrand, Johannesburg
...
The publication provoked near outrage among anthropologists, for two reasons:
(1) the naming of habilis as Homo required a redefinition
of the genus, including reducing the brain size required to
qualify as Homo; and (2) many argued that insufficient
“morphological space” divided Australopithecus africanus (the
presumed ancestor of habilis) and Homo erectus (the presumed
descendant)
...
2
...
” In the early days of paleoanthropology, the discovery of hominin specimens was
often accompanied by the proposal of a new species
...
By
the 1960s, anthropologists recognized what they should
already have knownanamely, that considerable anatomical
variation appears within populations
...


Further finds, more puzzles

Figure 21
...
This development, among other things, provoked a
strong reaction to its validity
...
)

lumping
...

For Homo habilis to be a valid species, it would have to be
intermediate between A
...
Lumpers expected considerable
anatomical variation in both africanus and erectus, which left
little or no room for an equally variable intermediate
...
Unfortunately, the
critics of habilis could not decide to which species it belonged;
some said that it was a large africanus, while others argued
that it was a small erectus
...
Nevertheless, the species’
history in the science has been rocky, principally because of
the large degree of anatomical variation found among specimens that are intermediate between africanus and erectus,
which are therefore putative members of habilis
...
That fossil, KNM-ER
1470, was the larger part of a cranium pieced together from
hundreds of fragments, and has been dated at 1
...
The face was large and flat, the palate was blunt
and wide, and, judging by their roots, the absent teeth would
have been large
...
Nevertheless, the cranium was large, estimated at
750 cubic centimeters, which betokened Homo
...

A year after the announcement of 1470’s discovery, a
second cranium was found at Lake Turkana, which was to
play an important role in the resolution of early Homo
...
(See figure 21
...
) Despite this disparity, 1813 has been described by some as a female Homo
habilis, though Leakey himself has not made this claim
...
The following year they published details of the
fossils, code-named OH 62 (and nicknamed “Lucy’s child”),
which they attributed to Homo habilis, and dated at between
1
...
75 million years old
...
Cranial remains were insufficient to estimate a brain
size
...

OH 62 was a small, mature female, comparable to Lucy in
being approximately 1 meter tall
...
The
unexpected aspect, as shown by Robert Martin of the Field
Museum, Chicago, and Sigrid Hartwig-Scherer of the
Anthropological Institute in Zurich, was that OH 62’s arms
were even longer than those possessed by Lucy, and its legs
shorter
...
(See figure 21
...
)
The year before OH 62 was found, the Homo erectus
(ergaster) youth had been unearthed on the west side of Lake
Turkana (see unit 24)
...
4 Body proportions of Lucy and “Lucy’s child”:
Comparisons of radius length against femur circumference (a) and
humerus length against femur circumference (b) indicate that
“Lucy’s child” (OH 62) is more apelike than its presumed ancestor,
Lucy (AL 288–1)
...
Hartwig-Scherer and R
...

Martin
...
3 Two skulls from Koobi Fora, Kenya: The
cranium KNM-ER 1470 (a) was found in 1972 and recognized as
belonging to the genus Homo, although no species attribution was
made initially
...
It is now attributed to Homo by most
observers
...
)

only 200,000 years later than OH 62
...
It would also require an evolutionary reversal, from moderately apelike limb proportions in
afarensis, to more apelike proportions in Homo habilis, to
humanlike proportions in Homo erectus (ergaster)athat is, if
OH 62 was indeed a member of Homo habilis
...
The question,
“Do you accept Homo habilis as a valid species?”, would likely
draw the response, “Well, it depends on which specimens
you want to include
...

One of the biggest surprises in the recent new finds was
that of Kenyanthropus platyops, a new species named by its
discoverers, Meave Leakey and her colleagues
...
5 million years, making it a contemporary of
Australopithecus afarensis
...
Does
this imply an ancestor–descendant link between K
...


0

143

1
cm

Figure 21
...

(Courtesy of F
...
G
...
)

The earliest known Homo
The strongest claims for evidence of Homo earlier than 2 million years come from the recent reassessment of a cranial
fragment from Kenya and a recently discovered mandible
from the site of Uraha in Malawi, which lies between East
Africa and South Africa
...
The structure around the eara
specifically the mandibular fossa, or jaw jointais diagnostic
of Homo
...
4 million
years old, making it close to that of the oldest known stone
tools, from Kenya and Ethiopia
...
5)
...
5 and 2
...

The authors assigned the Malawi specimen to Homo rudolfensis,
a contemporary of Homo habilis that is also found at Lake
Turkana (as described later in this unit)
...
5 million
years ago, and these two early specimens are consistent with
that hypothesis (see unit 5)
...
4 million years ago;
how much earlier it arose is a matter of speculation
...
(See
figure 21
...
)

Anatomy and biology of early Homo
As previously noted, the brain capacity of early Homo is larger
than that of the australopithecines, a change that produces
several associated anatomical characteristics
...
In early Homo, this constriction is
much reduced because of the expanded brain
...
The cranial bone itself is thicker in Homo than
in Australopithecus
...
The jaw and dentition
of Homo, however, are less massive than in the australopithecines
...
The patterns of wear on early Homo teeth are,
however, indistinguishable from those of the australopithecines: the pattern is that of a generalized fruit-eater
...
9 million years
ago does the toothwear pattern make a dramatic shift, perhaps indicating the inclusion of a significant amount of meat
in the diet
...
6 Sites of early Homo fossil
finds: The species attributions are those
suggested by B
...


Sterkfontein (habilis)

The original set of Homo habilis fossils from Olduvai Gorge
included a relatively complete hand, whose structure was
compatible with an ability to make and use tools
...
If australopithecines were equally skillful, then this explanation fails
...

Whether this separation was associated with the development of more complex subsistence activities or lay in the
realm of more complex social interaction (see unit 31) is
difficult to determine
...
All australopithecines
are characterized by the apelike form; Homo erectus/ergaster is
humanlike, as are certain specimens attributed to Homo
habilis
...

The shift from apelike body proportions to humanlike proportions is seen only in Homo, and is assumed to be associated
with an adaptive shift that includes greater routine activity
...
7 Comparisons of Homo rudolfensis and H
...
habilis
...
At the time of its discovery, the taxon
included dozens of specimens (from Olduvai, Lake Turkana,
and Sterkfontein) that displayed an uncomfortably wide
range of anatomical variation
...
In a major cladistic analysis published in Nature
in February 1992, Bernard Wood formally proposed two
species, a proposal that is widely accepted at present
...
7)
...
” Homo rudolfensis also has a larger

21: Early Homo
cranium
...
habilis and H
...
The small,
enigmatic cranium 1813 is included in H
...
The famous 1470 skull is
designated as Homo rudolfensis, together with a collection of
other specimens that includes examples of modern-looking
leg bones
...
rudolfensis
...
(In 1999, Wood and his colleague
Mark Collard proposed that both habilis and rudolfensis
should be assigned to Australopithecus rather than Homo
...
)
Other workers, such as Christopher Stringer and Richard
Leakey, agree that two species existed
...
Other suggestions have been put forth
as well
...
Although Wood’s taxonomic distinction
is based principally on certain cranial and dental characters, it
is useful to think of Homo habilis as a smaller-brained creature
with archaic postcranium, and H
...
Which of the two (if
either) gave rise to later Homo is still debated
...
habilis has a better
claim in this latter respect, but its smaller brain and archaic
postcranium militate against it
...

The discovery of the strikingly Homo-like Kenyanthropus
platyops has added a further uncertainty
...


KEY QUESTIONS
• How strong is the evidence that two species of early Homo
coexisted?
• How strong is the evidence as to which of these species might
have been ancestral to later Homo?
• What lessons are to be learned from the complex evolutionary
pattern that has apparently been uncovered in the Homo lineage?
• What shift in subsistence strategies might be consistent with the
change in body proportions between Australopithecus and Homo?

KEY REFERENCES
Aiello LC
...
J Human Evol 1992;22:127–147
...
Was “Lucy” more human than her
“child”? J Human Evol 1991;21:439–449
...
Earliest Homo
...

Johanson DC, et al
...
Nature 1987;327:205–209
...
Homoplasy and early Homo: an analysis of the
evolutionary relationships of H
...

rudolfensis
...

McHenry HM, Berger LR
...
africanus and the origin of the genus Homo
...

Miller JMA
...
Am J Physical Anthropol
2000;12:103–128
...
Oldest Homo and Pliocene biogeography of the
Malawi Rift
...

Stanley SM
...
Paleobiology
1992;18:237–257
...
Origin and evolution of the genus Homo
...

———
...
In: Meikle WE, et
al
...
Contemporary issues in human evolution
...

———
...
Human Evol 2000;15:39–
49
...
The changing face of genus Homo
...


HOMININ
RELATIONS

22

This unit will explore recent developments and current thinking
about how early hominins were evolutionarily related to one another
...


During the first half of the twentieth century, scholars commonly assigned a new species name to virtually each new
fossil unearthed
...
(See figure 22
...
) The result was a plethora of names
in the hominoid record
...
(See
figure 22
...
)
Lumping became the guiding ethic of anthropology
...
Although the single-species hypothesis is no longer considered valid, there is a persisting tendency to interpret
anatomical differences as within-species variation rather
than among-species variation
...
“The reason for this is, of course, that there is no
direct relationship, indeed no consistent relationship at all,
between speciation and morphological change,” says Ian
Tattersall, an anthropologist at the American Museum of
Natural History (see unit 4)
...
Unless the living animals are
available so that you can observe their behavior, it is often
impossible to know whether the individuals belong to one

Figure 22
...
(Courtesy of the
L
...
B
...
)

22: Hominin Relations
Figure 22
...
In its
early years, anthropology was dominated by
splitters, which yielded a plethora of species
...
Recently, a
swing away from lumping has occurred, but
not a return to the previous excesses
...
As a result, it is obviously easier to subsume
anatomical differences under within-species variation rather
than to argue for separate species
...
The result, argues
Tattersall, “is simply to blind oneself to the complex realities
of phylogeny
...

Although most anthropologists would regard Tattersall’s
position as somewhat extreme, many are coming to accept
that hominin phylogeny is more complex than it is usually
portrayed
...
Cladistic methodology appears to offer the
most promising approach for overcoming the problem of
lumping (see unit 8)
...
As discussed in unit 8, only those similarities that result from a
shared evolutionary history (homologies) can reliably lead to
accurate phylogenies
...
Most anthropologists now accept that homoplasy has been common in hominin evolution but, as we will
see later in this unit, less agreement has been reached regarding which traits are homoplasies between certain lineages
and which are not
...

A further obstacle to accurate phylogenetic reconstruction
arises from the way in which different traits are treated
...
In one of the more complete cladistic analyses of hominin phylogenetics, Randall

147

More species
Anatomical variation seen as:
Intraspecific

Interspecific

Skelton, of the University of Montana, and Henry McHenry,
of the University of California, Davis, employed 67 such
traits
...

If all 67 traits were independent, then they would provide
information on 67 evolutionary transformations, forming a
powerful body of evidence
...
For
instance, an important trend in early hominin evolution was
toward heavy chewing in order to process tough plant foods
...
Bigger teeth and more powerful chewing also
require a more robust mandible, changes in face structure,
and possibly alterations in the mechanics of muscles that
move the jaws
...

Thus, phylogenetic analyses should logically group traits
into functional packages, rather than treat them as independent
...

Grouped in this way, the 67 traits give phylogenetic information on just five evolutionary transformationsanot 67
...
3
...
For instance, the
evolution of traits associated with anterior dentition is linked
in part to the evolution of heavy chewing, as is the shape of
the face and certain cranial traits, such as the possession of a
sagittal crest
...

Traits associated with heavy chewing are obviously the most
common, because teeth and jaws are the most resilient parts
of the cranium and consequently become part of the fossil
record much more frequently
...
3 Interdependence of characters: Individual
anatomical traits are typically parts of functional complexes and are
not evolutionarily independent
...


have concentrated much of their work on teeth and jaws,
including basing phylogenetic reconstruction on them
...
Teeth and jaws, and their interpretation, may therefore receive more attention than their
phylogenetic reliability justifies
...
afarensis were discovered no consensus had been reached
on whether they represent one extremely sexually dimorphic species or two less variable species (one large and one
small)
...
9 and 2
...
The
discoveries of more A
...
(See unit 19
...
afarensis
proved false the often implicit assumption that A
...
The likelihood that ramidus and anamensis, for instance, were part of a
bushy phylogeny prior to afarensis, rather than being stages
in a single, transforming lineage, impacts the status of afarensis
...
) It is unlikely that a phylogenetically
bushy clade would be reduced to a single species, which then
gives rise to further bushiness
...

Further fossil finds in the period 5 to 3 million years ago will
be necessary to resolve this issue
...
aethiopicus in the evolutionary
tree: Is it ancestral to the two later robust australopithecines,
or is it separate from them? The issue of the origin of the
genus Homo concerns the identity of its direct ancestor: Is it A
...
africanus, or some as yet unknown third species?
These two questions will be considered through Skelton and
McHenry’s cladistic analysis, not because it is universally
accepted (it is not, but it is widely respected), but because it
offers a strategy for addressing some key problems, particularly that of homoplasy
...

• The relationships among the robust australopithecines (A
...

• The origin of the genus Homo
...
4
...
afarensis
to early and later hominins

Relationships among
the robust australopithecines

The Skelton/McHenry analysis
Skelton and McHenry performed a cladistic analysis of the
67 cranial traits in several ways: they treated the traits as if
they were independent; they compared the five functional
complexes discerned; and they grouped the traits by anatomical region (face, anterior dentition, posterior dentition,

Origin of the genus Homo

Figure 22
...


22: Hominin Relations

2
...
0

africanus

WT

3
...
0
Hadar

Hadar
17000
and Laetoli 4
...
0

anamensis
ramidus
5
...
0

2
...
0

3
...
0

4
...
0

Humans

1
...
0

ramidus
Hypothesis two

boisei

Hypothesis one

robustus

?

anamensis

aethiopicus

Time (mya)

2
...
0

0
Humans

0

Time (mya)

mandible, palate, basicranium, and cranial vault), which is
another way of overcoming linkage between traits
...
Their
study was performed prior to the discovery of Ardipithecus
ramidus and Australopithecus anamensis, and it took the conservative position that Australopithecus afarensis is indeed a
single species
...
One of the most important, and controversial, conclusions of their work was that
traits associated with heavy chewing in hominins are subject
to homoplasy
...
Traits associated with
heavy chewing are least developed in A
...
boisei
...
aethiopicus,
also possesses large cheek teeth and a robust mandible,
which many anthropologists interpret as indicating an ancestral relationship to A
...
robustus
...

aethiopicus, however, is more similar to that of A
...
The degree of prognathism in A
...
afarensis, while the other robust australopithecines are much less
prognathic and more similar to Homo
...
Analyses using posterior dentition, an anatomical region associated with heavy chewing, produce the same phylogenies
...
(See figure 22
...
) In this tree, A
...
afarensis that became extinct with no
descendants
...
aethiopicus and the other two robust australopithecines
are homoplasiesanot the result of common ancestry
...
boisei and robustus) and earliest Homo (discussed
below)
...

Skelton and McHenry’s phylogeny is as follows
...
They propose that
afarensis gave rise to an as yet unknown species that was
aethiopicus-like in some ways (in traits not related to heavy

149

anamensis

anamensis

ramidus
5
...
0

Hypothesis four

Figure 22
...
Hypothesis 4 is based on Skelton and McHenry’s
analysis, and shows the hypothetical ancestors as open boxes
...


chewing); this species was the common ancestor of aethiopicus on one hand, and gave rise to A
...
Australopithecus aethiopicus is therefore viewed as a side branch
that became extinct, while A
...
Australopithecus africanus is derived from the aethiopicus-like ancestor,
and in its turn gave rise to another proposed africanus-like
species; this species was the common ancestor of earliest
Homo on one hand and the robust australopithecines (via a
proposed robustus-like common ancestor) on the other
...
The close relationship between
Homo and A
...
boisei (they share a common
ancestor to the exclusion of other hominins) is reflected in a
more flexed cranial base, a deeper jaw joint, less prognathism,
and greater encephalization compared with A
...


150 Part Five: The Hominin Adaptation
This phylogenetic scheme, like other proposed alternatives, implies considerable homoplasy in hominin evolution,
particularly in the heavy chewing complex
...
aethiopicus was ancestral to the other robust
australopithecines, and that heavy chewing traits are homologous (not homoplasic)
...
This phylogeny
shifts the requirement for homoplasy to other traitsanamely,
anterior dentition, basicranial flexion, encephalization, and
prognathism/orthognathismathat A
...

A second area of homoplasy appears in the evolution of
Homo
...
afarensis
...
A study
of the ontogeny of facial development reveals that the
formation of facial anatomy in Homo is unique, not a primitive retention
...
If, as Skelton and McHenry
point out in their analysis, the face and dentition of Homo are
indeed uniquely derived, then these traits provide no useful information about the large-toothed australopithecine
(known or yet to be discovered) from which it evolved;
other, shared traits, such as basicranial flexion and orthognathism, are necessary to link Homo to A
...

Skelton and McHenry’s preferred phylogeny is one of
several that can been seen in the anthropological literature;

its strength, however, lies in its cladistic methodology and
thoughtful treatment of potential biases
...
afarensis, for instance,
and designate A
...
The most controversial aspect of
the Skelton/McHenry phylogeny is its suggestion that the
robust australopithecines are not monophyletic
...
africanus rather than from A
...
boisei considered controversial?
• What kind of fossil discovery would most upset current views of
hominin phylogeny?

KEY REFERENCES
Foley R
...
Evol Anthropol 2002;11:32–37
...
Homoplasy, clades, and hominid phylogeny
...
, eds
...

San Francisco: California Academy of Sciences, Memoir 21, 1996
...
Human origins
...

Skelton RR, McHenry HM
...
J Human Evol 1992;23:309–349
...
A reappraisal of early hominid phylogeny
...

Tattersall I
...
J Human Evol 1992;22:341–349
...
Origin and evolution of the genus Homo
...
, eds
...
San Francisco:
California Academy of Sciences, Memoir 21, 1996
...
5-plus million years ago
...

However, several lines of evidence indicate that australopithecines
might have been the first tool makers
...


Stone artifacts have been collected by amateurs and professionals alike for centuries and studied as evidence of earlier
societies
...
Today a strong interest
has developed in studying artifacts within the subsistence
context of early hominins
...

Stone-tool assemblages have been classified into five categories, or modes, that are defined by characteristic artifacts in
them
...
1
...
Mode I technology, the
earliest, is based on simple chopping tools that are made by
knocking a few flakes off a small cobble
...
In mode III, large
cores are preshaped by the removal of large flakes and then
used as a source of more standardized flakes that are

retouched to produce a large range of artifacts
...
Mode V consists of microlith technology,
which, as implied, constitutes the production of small, delicate artifacts
...

Desmond Clarke, of the University of California, Berkeley,
permits a description of the characteristics of archeological
assemblages, not of archeological time period
...
6 million years
ago and persisted (as an opportunistic practice) until historical times
...
For instance, mode
IV (blade tools) were produced in Africa nearly 250,000 years
ago, but did not enter the European record until 40,000 years
ago
...

For reasons related to the development of the science
of archeology, a different terminology is used to describe
archeological time periods in sub-Saharan Africa and those
in Eurasia
...
It is divided into three parts: the
Earlier Stone Age (ESA), the Middle Stone Age (MSA), and
the Later Stone Age (LSA)
...
These
stages have been defined according to cultural evolutionaa
somewhat confusing system given that, while the boundaries
between the stages are relatively clear in Eurasia, Africa has
been associated with a more continuous flow of development
...
As mentioned earlier, the timing of first appearance
of characteristic cultural artifacts (such as blades) often varies
between the two geographic regions
...
6M

Bearing in mind the elasticity of stage boundaries, technology development unfolded as follows
...
6 million years ago; the entire ESA includes the first
appearance of mode II, approximately 1
...
Traditionally, the LSA was characterized by the
first appearance of blade tools and artifacts of personal
adornment (mode IV), such as beads, some 60,000 years ago
...

In Eurasia, the Lower Paleolithic begins when humans
moved beyond Africa, perhaps close to 2 million years ago
(see unit 27), and ends with the first appearance of prepared
cores (mode III), some 200,000 years ago
...
The Upper Paleolithic begins with the first appearance of

Figure 23
...
(See text for
details
...

This unit will focus on the first part of the African Earlier
Stone Age
...
The archeology associated with
the origin of modern humans (the MSA and LSA of Africa
and the Upper Paleolithic of Eurasia) is the subject of unit 30
...
6 million years ago, and are known from
sites in the Lower Omo Valley, the Hadar region, and the
Gona region of Ethiopia, and the western shore of Lake
Turkana, Kenya
...
Most tools dating
from the period 2
...
5 million years ago were made from

23: Early Tool Technologies
lava cobbles, and constitute a range of so-called core tools
and small, sharp flakes
...
(The gorge was
once called Oldoway Gorge; hence the derivation of the tool
technology’s name
...
9 to 1
...
The artifacts fall into
four categories:
• Tools, which include types such as scrapers, choppers, discoids, and polyhedrons;
• Utilized pieces, such as large flakes produced in the manufacture of tools, having sharp edges useful for cutting;
• Waste, or small pieces produced in the manufacture or
retouching of tools and utilized pieces that had no use; and
• Manuports, which are pieces of rock carried to a site but
not modified
...
The different
forms tended to flow into one another typologically, and
they carry an air of opportunistic production
...

Frequently the labels applied to the various core forms
implied function, such as scrapers and choppers
...
In the early 1980s, however, a series of experimental
studies by Indiana University archeologist Nicholas Toth led
to the conclusion that the real tools in the Oldowan assemblages were the flakes, and that the core forms represented
the by-products of flake production
...
2–23
...
)
Toth discovered that undirected flaking of cobbles of different shapes led automatically to specific core forms, depending on the shape of the cobble used
...

In experimental butchering, Toth found that the most effective implement for slicing through hide was a small flake; a
similar finding applied to dismembering and defleshing
...
A heavy core
or unmodified cobble was effective for breaking bone to gain
access to marrow or brain
...
Flakes and scrapers

153

Figure 23
...
(top row) Hammerstone,
unifacial chopper, bifacial chopper, polyhedron, core scraper,
bifacial discoid
...
An actual tool
kit would comprise mainly flakes
...
)

Figure 23
...
(Courtesy of Nicholas Toth
...
Nuts
could be cracked easily with an unmodified stone hammer
and anvil
...
Nevertheless, Toth and Lawrence
Keeley, of the University of Illinois, examined 54 flakes from
a 1
...
Four had been used in butchering, three

154

Part Five: The Hominin Adaptation
their source of energy, which was important in the further
expansion of the brain (see unit 31)
...
4 Tool profile: A chopper and the flakes produced
during its manufacture
...
)

were applied to wood, and two were associated with soft
vegetation
...
The small, sharp flake is,
however, probably the most important implement and represents a technological and economic revolution
...
The use of digging
sticks permitted more efficient access to underground food
sources, such as tubers
...
Although the Oldowan industry is technically rather crude, the regular production of flakes is not a
matter of chance
...
5 and 23
...
) Three conditions must be met by a stone knapper who wishes to produce
flakes routinely by percussion
...
Second, the core must be struck with a glancing
blow about 1 centimeter from the acute edge
...
By examining the composition of cores and
flakes at archeological sites, Toth could infer that the tool
makers of 2
...
5 million years ago had indeed mastered
the percussion stone-knapping skill
...
Toth demonstrated that of the three possible
techniques for producing flakesapercussion, anvil (striking
the core on a stationary anvil), and bipolar (striking the core
with a hammerstone while it rests on an anvil)apercussion
was the most efficient
...

A debate over how much skill is required to carry out this
simplest of stone knapping has recently been addressed in
a most interesting fashion: by asking a bonobo (pygmy

5

10 cm

Bifacial chopper

Heavy-duty scraper

Light-duty
side scraper

Light-duty
scraper

Outil écaillé

Awl

Figure 23
...


23: Early Tool Technologies

155

Hammerstone

Platform of flake
Flake to be removed

Percussion angle =
Less than 90 degrees

Core side view
Point of percussion,
with negative bulb

Flake to be removed

Cortex (natural
stone surface)
Flake scar
Core front view

Cortex

Figure 23
...
Flakes
produced in this manner have certain
features produced by concoidal fracture
...
)

Platform
Bulbar scar
Bulb

Dorsal scars
Fissures
Ripple marks
Flake

chimpanzee) to make Oldowan tools
...
In 1989, the two researchers published a paper called “An ape’s view of the Oldowan,” in
which they asked the following question: “When in human
evolution did our ancestors cease behaving like apes?” In
other words, given the opportunity and motivation, could an
ape make Oldowan tools?
Toth had an opportunity to test this experimentally, when
he collaborated with Sue Savage-Rumbaugh, of Georgia
State University
...
Toth encouraged Kanzi to make sharp stone flakes in
order to gain access to favored food items enclosed in a box
that was secured with string
...

Despite being shown the percussion knapping technique,
however, he never used it
...
Kanzi knew what he needed (sharp
flakes) and figured out ways to obtain them (banging or
throwing rocks), but he was not an Oldowan tool maker
...


Who made the tools?
In the period 2
...
5 million years ago, several hominin
species (Homo and Australopithecus) lived as contemporaries
(see unit 22)
...
The argument from parsimony,
therefore, would be that the earliest technology was also the
product of Homo
...
5 million years ago (see unit 21)
...
He bases his contention on the anatomy of the hand bones, and particularly
the thumb, gathered from deposits in the cave of Swartkrans,
South Africa
...
8 million years ago, also contain stone tools and
putative digging sticks
...
Recent detailed studies of the thumb have
indicated that it was capable of forming a power grip, which
is important in percussion stone knapping
...
Susman concludes that,
although early australopithecines were unable to make tools,
later species, including early Homo, may have possessed this
capacity
...

As Susman points out, 95 percent of the hominin cranial
bones found are those of Australopithecus, suggesting “an
overwhelming probability” that the hand bones are indeed
remnants of this species
...

Some observers contend that this evidence is too tenuous for
definitive conclusions to be drawn
...
No specimens of Homo
have been discovered in the area
...
Tracing the identity of the first tool makers
...

Gibson KR, Ingold T, eds
...
Cambridge, UK: Cambridge University Press, 1993
...
Microwear polishes on early tools from Koobi
Fora, Kenya
...

Panger MA, et al
...
Evol Anthropol 2002;11:235–245
...
Making silent stones speak
...

Semaw S, et al
...
5-million-year-old stone tools from Gona, Ethiopia
...

Susman RL
...
Science
1994;265:1570–1573
...
The Oldowan reassessed
...

Toth N, et al
...

J Archeol Sci 1993;20:81–91
...
The oldest whodunnit in the world
...

Wynn T, McGrew WC
...
Man NS
1989;24:383–398
...
Now, however, many
scholars believe that the specimens assigned to Homo erectus in fact
represent two species, Homo erectus and Homo ergaster, with
ergaster being the precursor of erectus
...


This unit deals with the species of Homo that has been
assumed to be intermediate between early Homo (habilis/
rudolfensis) and modern-day humans, Homo sapiens
...
Roughly 1 million years ago, Homo erectus
expanded its range beyond Africa, first into Asia and then
into Europe, developing geographically variable populations
...
(See units 27 through 30
...
It will be helpful to
give a snapshot of evolutionary events as currently viewed
by most anthropologists
...

Homo ergaster expanded its range beyond Africa and into Asia
soon after its origin and at least by 1
...
Homo erectus

expanded its range throughout Asia, back into Africa, and
presumably into Europe, although few unequivocal fossils
have been found (most evidence takes the form of the
stone-tool technology often associated with the species)
...


A brief history of discovery
The first discoveries of Homo erectus were made in 1891 and
1892 in Java, Indonesia, by Eugene Dubois, a Dutch medical
doctor, who had gone there specifically to search for “the
missing link
...
Although he was initially ambivalent
over the human nature of his fossil find, Dubois eventually
came to name the species Pithecanthropus erectus, or upright
ape man, inspired in part by Ernst Haeckel’s speculations on
human ancestry (see unit 3)
...
1
...

The rehabilitation of Pithecanthropus erectus as an important
discovery in human evolution coincided with discoveries in
China, at the Choukoutien (now Zoukoutien) site near
Peking (now Beijing)
...

He named it Sinanthropus pekinensis, or Chinese man from
Peking
...
Within a decade a rich haul had accumulated,
including 14 partial or fragmentary crania, 14 mandibles,
more than 100 teeth, and many other fragments
...
1 Dubois’s view: In his first reconstruction of
Pithecanthropus (1896), Dubois reflected his ambivalence over the
human nature of the fossil, and chose to emphasize an apelike
nature, seen in the prognathism and large canines
...
Black
died prematurely of a heart attack in 1934, and his work was
continued by the German anatomist Franz Weidenreich
...
H
...
Many Pithecanthropus teeth and jaw and cranial
fragments were recovered, including the almost complete
cranium of a child from the Modjokerto site
...
The issue of provenance of the fossil, or its exact location in the sediments from
which it was recovered, was therefore often a serious problem
...
This caveat applies particularly to the Modjokerto
skull, found in 1936, as we will see below
...
(See figure 24
...
)
Since the 1950s, discoveries of Homo erectus fossils have
been made sporadically, principally in Africa, but also in Asia
...
3
...
Later
finds in northern Africa were made at Sidi Abderrahman
(a jaw), in Morocco soon after the first Ternifine find, and at
Salé (cranial fragments), also in Morocco, in 1971
...
2 million years (although it is probably younger)
...
Fossil prospecting in Java contributed an important
cranium (Sangiran 17) in 1969 and a face and cranium
(Sangiran 27 and 31) in the late 1970s in the Sangiran dome
region of the island
...
2 Homo erectus: These
two reconstructions by Weidenreich
of Zoukoutien Homo erectus (top) and
Indonesian Homo erectus (bottom) show some
of the anatomical variations present in
Asian Homo erectus
...
7)

Ternifine,
Algeria (0
...
4)

Sidi Abderrahman

Figure 24
...
Until recently, no fossil
specimen outside of Africa was dated as
being older than approximately 1 million
years
...


Salé

Nariokotome (1
...
25)
Swartkrans (1
...
These sites have yielded
both the oldest known and the most complete specimens
...
8 million years,
and a brain size of 850 cubic centimeters
...
(See figure 24
...
) The boy stood more
than 5 feet tall when he died, and would have exceeded
6 feet had he lived to maturity
...
And his body stature and proportionsa
tall, thin, long arms and legsaare typical of humans adapted
to open, tropical environments (see unit 11)
...
5
...
First, anatomical variations,
which were seen initially in Asia, appeared to have proliferated elsewhere
...
In
recent years, both of these assumptions have been challenged
...
Even where the
presence of volcanic tuffs makes radiometric dating possible,
as in Java, uncertainty has arisen over the reliability of such
dates because of questions about provenance, as explained
earlier
...
3)
Koobi Fora,
Kenya (1
...
13)

Hexian
Lantian, China (0
...
6)

Sangiran (1
...
8)

erectus specimen outside of Africa was older than approximately 1 million years
...
The oldest
non-African Homo erectus sites were held to be in Java, with
estimates of a little more than 1 million years for the
Modjokerto child and something close to 750,000 years for
Sangiran 27/31
...
8 million years
...
This
apparent delay constituted a major puzzle to be explained
in the overall history of Homo erectus
...
This technology, the Acheulean industry (see
unit 25), is first seen in the archeological record some 1
...
A new fossil find in 1992 and the redating of
certain Javan fossils in 1994 implied one of two things: either
no delay occurred, and Homo erectus expanded its range
beyond Africa as soon as it evolved there, or Homo erectus
evolved in Asia, not Africa, close to 2 million years ago
...
Its ageainferred from faunal correlationawas said to be
1
...
8 million years
...
In early
1994, Carl Swisher and Garniss Curtis, of the Geochronology
Center, Berkeley, announced new dates (based on singlecrystal laser fusion; see unit 7) for the Modjokerto and
Sangiran fossils: 1
...
6 million years, respectively
...

Some anthropologists are reluctant to accept the new
dates, however, because of the lingering uncertainties about
the provenance of the Modjokerto find
...

Although KNM-ER 3733 and the Modjokerto skull are of
equivalent age, a sufficient margin of error exists in the dates
to permit a gap in age of at least 100,000 years
...

An African origin followed by population expansion into
Asia is therefore consistent with the dates as currently
known
...


Changing views: anatomy and
evolutionary pattern

Figure 24
...
(Courtesy of Alan Walker/National Museums of Kenya
...
The early African specimens, such as
KNM-ER 3733, the slightly younger 3883, and WT-15,000
(the Turkana boy), have been assigned to a new species,
Homo ergaster, while the Asian specimens remain as classic
Homo erectus
...
6
...
In this hypothesis, the later presence of erectus
in Africa (such as the robust OH 9 from Olduvai Gorge) is
interpreted as an Asia-to-Africa population expansion
...
(See figure 24
...
)
Many aspects of ergaster and erectus anatomy are, of course,
similar, with the principal differences being a higher cranial
vault, thinner cranial bone, absence of a sagittal keel, and
certain cranial base characteristics in ergaster
...

The body size of ergaster/erectus also represents an increase
relative to that of early Homo, and reached nearly 1
...
55 meters and 52
kilograms in females; this size compares with 52 and 32 kilo-

24: The Changing Position of Homo erectus
Homo sapiens

163

Homo erectus
Slight postorbital
constriction

No sagittal keel
Pronounced postorbital
constriction

Sagittal keel

Low, flat forehead

Vertical forehead

Prominent brow
ridges

Slight brow
ridges

Occipital torus
Large facial skeleton
with large orbits and
large nasal opening

Relatively small
facial skeleton
Rounded
occipital

Relatively small
teeth

Angular occipital

Relatively large
teeth
Large mandible

Small mandible

Figure 24
...


grams, respectively, for male and female habilis
...
Equally significant is the fact that the difference in
body size between males and females is far less than that
observed in all earlier hominins
...
For instance,
perhaps the greater complexity of ergaster/erectus lifeways
included a degree of male–male cooperation (see unit 13)
...
6 million years old, the postcranial anatomy was
known from only a few elements, such as the femur and
pelvis
...
ergaster is similar to that of modern humans, but more robust and heavily
muscled; this structure implies routine heavy physical exertion
...
This combination repres-

Figure 24
...
8 million years old
...


ents something of a mix between modern human and
australopithecine anatomy: modern humans have a short
femoral neck attacked to a large head, while australopithecines possessed a long neck and a small head
...
This structure has been interpreted to imply less control over breathing patterns than
in modern humans, related to the absence of an ability for
spoken language (but see unit 32 for a qualification)
...
The birth canal was smaller
than in modern humans, but its absolute size suggests that
humanlike infant development appeared for the first time
...
An apelike pattern of development (a brain-size doubling from birth to maturity) would
lead to an adult brain of less than 600 cubic centimeters,

164

Part Six: Homo erectus: Biology and Behavior
Africa
Modern

Present

Eurasia
Humans

Million years ago

?

Archaic
sapiens

?

1
...
e

H
...
0

H
...
rudolfensis

which is significantly smaller than actually develops
...
Infant helplessness and prolonged childhood might
therefore have already begun in Homo ergaster, thus giving an
opportunity for more cultural learning
...

In an analysis of tooth development as an indicator of lifehistory patterns, Holly Smith, of the University of Michigan,
has also produced evidence for a shift to a life-history pattern
similar to that seen in modern humans (see unit 12)
...
9 years and 66 years, respectively
...
While late
Homo erectus fit the modern human pattern, as do Neanderthals and other archaic sapiens, Homo ergaster was somewhat
intermediate between humans and apes; its first molar eruption occurred at 4
...

For the Turkana boy, a recent analysis of tooth development shows that it is fast paced, giving the boy’s age at death
to have been around 8 years
...
7 A postulated phylogeny:
Homo ergaster is seen here as being the
descendant of H
...
erectus
...
ergaster gives rise to modern humans,
which replace established archaic
populations
...
Walker, who was one of the authors of the study,
together with Christopher Dean and others, concludes that
this calls into question his earlier conclusion about brain
growth and prolonged childhood
...

The accumulations of bones and stones that appear in the
archeological record coincidentally with the origin of the
genus Homo become more frequent through ergaster and
erectus times, giving an increasingly clear putative signal
of some hunting activity (see unit 26)
...
Whatever the niceties of taxonomy, the evolution of ergaster/erectus signals the appearance of a new grade
of hominin evolution
...

Thus, these species were apparently capable of a life more
complex and varied than had previously been possible
...
Homo erectus features used in cladistics and their
variability in Asian and African hominids
...

Brown FH, et al
...
Nature 1985;316:788–792
...
Growth patterns in teeth distinguish modern humans
from Homo erectus and earlier hominins
...

Gabunia L, et al
...
Science 2000;288:1019–1025
...
Dmanisi and dispersal
...

McHenry HM
...
J Human Evol 1994;27:77–87
...
Grandmothering and the evolution of Homo erectus
...

Rightmire GP
...

Smith H
...
Ossa 1989;14:63–96
...
Age of the earliest known hominids in Java,
Indonesia
...

Vekua A, et al
...

Science 2002;297:85–89
...
The Nariokotome Homo erectus skeleton
...

Wood B
...
Nature
1992;355:783–790
...
The changing face of genus Homo
...

Wood B, Turner A
...
Nature
1995;378:239–240
...
Known as the Acheulean, the assemblage is characterized
by large forms, particularly the handaxe, which required greater skill
in conceptualization and manufacture
...
The Acheulean
is seen first in Africa, and later in Eurasia, but not in East Asia
...


As we saw in unit 24, the evolution of Homo ergaster and subsequent appearance of Homo erectus brought many changes in
the biology of our direct ancestors
...
In particular, the further development of
meat as a significant component of diet (see unit 26) must
have been very important, both in increasing the stability
and richness of energy resources and in allowing new
habitats to be exploited
...
It might be expected that these developments would
be accompanied by significant enhancement of stone-tool
technologies
...
The earliest known example of this assemblage
comes from Konso-Gardula, Ethiopia, and is 1
...
The name derives from the site of St
...
The innovation consisted of the introduction of larger toolsaknown as handaxes,
picks, and cleaversathan appear in Oldowan assemblages
...
1 and 25
...
) Although each of these tools is

Figure 25
...
(bottom
row) Spheroid (quartz), flake scraper, biface trimming flake
...
(Courtesy of Nicholas Toth
...
Compared with
Oldowan choppers, Acheulean handaxes required a higher
level of cognitive ability in the conceptualization of the endproduct and its manufacture and greater precision in their
manufacture
...
Several interpretations of this temporal gap have been
suggested
...
Alternatively,
the Acheulean may have been a Homo erectus innovation
...
2 Early bifaces from Africa:
Drawings of (a) a pointed handaxe, (b) an
ovate handaxe, and (c) a cleaver
...


assemblages of the appropriate age in eastern Asia lack characteristic Acheulean artifacts (as discussed later in this unit)
...
Glynn Isaac argued, for instance, that
it required the production of large ovoid flakes, greater than
10 centimeters long, which were then trimmed by a few or
many repeated blows along both edges
...
The
regular production of large flakes according to a preferred
shape would have represented a punctuation in technological expression upon which other bifacial implements
could be built
...
The Developed Oldowan (see unit
23) included small bifaces, sometimes constructed from
ovoid cobbles and sometimes derived from relatively large
flakes
...

Once the large, bifacial handaxe appeared, it remained a
characteristic of Acheulean assemblages for a very long time,
in both Africa and Eurasia
...

While no early handaxe was the product of long, careful
flaking to yield an esthetically pleasing, perfectly symmetrical teardrop shape, many late examples appeared as
crude as the earlier versions
...
This core preparation, known as the Levallois technique (named after the site in France where the first
examples of later prepared-core assemblages were found),
became especially dominant in Middle Stone Age and Middle
Paleolithic technologies
...

Acheulean assemblages are known from many sites in
Africa, some of which are spectacularly rich
...
This industry persisted until roughly 200,000
years ago, when it is superseded by Middle Stone Age (Middle
Paleolithic) assemblages
...
3 million
years of the Acheulean period, for reasons that remain
unclear
...

The earliest Acheulean site outside of Africa is Ubeidiya,
west of the Sea of Galilee, in Israel
...
Migration into Europe may
have followed the same route, or it may have moved across

168

Part Six: Homo erectus: Biology and Behavior

the narrow Straits of Gibraltar from northwestern Africa to
Spain, or it may have involved island hopping across the
Mediterranean; it may also have occurred via any combination of these paths
...
Early sites include Isernia in
Italy (700,000 years) and Vértesszöllös in Hungary and Arago
in France (both somewhat older than 300,000 years)
...

Acheulean sites in Europe begin to appear soon after 500,000
years ago
...

Many Acheulean industries in Africa, Europe, and Asia
bear local names
...


Geographical distribution of
the Acheulean
The earliest Acheulean assemblages are located in Africa, but
later sites are found in western Asia and Europe
...

(See figure 25
...
) Stone-tool assemblages east of the so-called
Movius line take on the chopping-tool form
...


Bifaces
Non-bifaces (chopping tools)

Movius, for example, considered the hominins in the east to
be less evolutionarily developed than hominins elsewhere
...
”
Some scholars suggest that the pattern is simply the result
of an absence of suitable raw material for fashioning large
bifaces east of the Movius line or that other material allowed
the manufacture of tools that substituted for Acheulean
handaxes
...

He points out that the region is rich in bamboo, an extremely
versatile raw material that is used in the modern world for
applications ranging from furniture to scaffolding in the
building of skyscrapers
...

Others suggest that the pattern reflects a division of
cultural tradition, and has no functional or technological
significance
...
If, as seems likely, Homo ergaster extended
its range beyond Africa soon after it arose, then the first occupants of Asia would have long predated the first appearance
of the Acheulean technology
...


Figure 25
...
The dividing line
between the two regions is called the
Movius line
...
A particularly unlikely explanation is that
they were used as lethal projectiles, thrown like discuses as a
means of killing prey
...
In experimental studies, Indiana University archeologist Nicholas
Toth found that handaxes (and cleavers) were highly effective at slicing tough hide, such as that of elephants
...

Microwear studies by Lawrence Keeley, of the University of
Illinois at Chicago, reveal that handaxes were used for many
functions, and for materials ranging from meat and bone to
wood and hide
...

The end of the Acheulean industries, which occurred from
300,000 to 200,000 years ago throughout some areas of the
Old World, marked the end of these stone-tool assemblies
that had few artifact types and enjoyed enormous longevity
...
The end of the Acheulean brought the Lower
Paleolithic (Early Stone Age) to a close and marked the
beginning of the industries of the Middle Paleolithic (Middle
Stone Age)
...
Real technical innovation had begun, although
even this development was overshadowed by what followed
in the Upper Paleolithic (Later Stone Age) (see unit 30)
...
The earliest Acheulean from Konso-Gardula
...

Carbonell E, et al
...
J Anthropol Archeol 1999;18:119–128
...
Chinese stone tools reveal high-tech Homo erectus
...

Gowlett J
...
In: Bailey G, Callow P, eds
...
Cambridge, UK: Cambridge University Press, 1986:243–260
...
Bamboo and human evolution
...

Schick KD, Toth N
...
New York: Simon
and Schuster, 1993
...
Early Paleolithic of China and Eastern Asia
...

Wynn T
...
J Anthropol
Archeol 1993;12:299–322
...
Mid-Pleistocene Acheulean-like stone technology of
the Bose Basin, South China
...


HUNTER OR
SCAVENGER?

26

Interpretations of the lifestyle of early Homo have undergone many
changes
...
These days, their lifestyle is regarded as considerably less “human” than this implied
...


Some time between the beginning of the hominin lineage
and the evolution of Homo sapiens, an essentially apelike
behavioral adaptation was replaced by what we would recognize as human behavioranamely, the hunter-gatherer way of
life
...
As we have seen, fossil evidence reveals the fundamental anatomical changes during this
period, but it is to archeology that one turns for direct
evidence of behavior
...
6 million years ago (see unit 23),
which coincides closely with the earliest evidence of the
genus Homo
...
What
this association between bones and stones means in terms of
early hominin behavior has become the subject of heated
debate among archeologists
...

Others have countered by suggesting that these combinations merely indicated that hominins used the stones to
scavenge for meat scraps and marrow bones at carnivores’
kill sites; according to this hypothesis, the associations had no
social implications
...


Early hypotheses and recent
developments
During the 1960s and early 1970s, paleoanthropologists
considered hunting to be the primary human adaptation, a
notion that has deep intellectual roots, reaching back as far as
Darwin’s Descent of Man
...
” The
conference not only stressed the idyllic nature of the huntergatherer existencea“the first affluent society” as one authority
termed itabut also firmly identified the technical and organizational demands of hunting as the driving force of hominin
evolution
...
” Cooperation was what made us human, argued
Isaacaspecifically, cooperation in the sharing of meat and
plant food resources that routinely were brought back to a
social focus, the home base
...
As for “Man the Hunter,” Isaac claimed that
it was not possible to evaluate the importance of hunting
relative to that of scavenging
...

Although the shift from the hunting hypothesis to the
food-sharing hypothesis changed what was perceived to
be the principal evolutionary force in early hominins, it
nevertheless left them recognizably human
...

Although the food-sharing hypothesis was often described
by proponents as merely one of many possible candidates for
explaining the evolution of human behavior, it proved very
seductive
...
1 An evolution of
hypotheses: During the past four decades,
ideas about the nature of early hominin
subsistence (social and economic) activities
have passed through several important
stages
...

In the 1970s, the image shifted, with the
focus emphasizing social and economic
cooperation through a mixture of hunting
and gathering in a protohuman context
...
The
current position is that scavenging was
probably a very important route of meat
acquisition, but not the exclusive one;
this view is taken within the context of a
human/animal model
...
” (See figure 26
...
)

Testing assumptions
Realizing that several assumptions were implicit in these
interpretations, in the late 1970s Isaac initiated a program of
research that would test the food-sharing hypothesis
...
Both studies addressed
several basic issues
...
8-million-year-old sites at Olduvai Gorge and a
newly excavated, 1
...
(See figures 26
...
4
...

In fact, bone fragments and stone artifacts might accumulate at the same site and yet be causally unrelated for several
reasons (see figure 26
...
For instance, they might be independently washed along by a stream and then deposited
togetheraa hydraulic jumble, as it is known
...
The first possibility can be tested by the detailed
stratigraphy of the site
...
(See figure 26
...
)
Of the six major early bone and artifact sites at Olduvai bed
I, the most famous site is the Zinj “living floor,” which
includes an accumulation of more than 40,000 bones and

172 Part Six: Homo erectus: Biology and Behavior

W

E

Figure 26
...
5-million-year-old
site: Excavated on the floodplain east of
Lake Turkana, site 50 has yielded 1405
stone fragments and 2100 pieces of animal
bone
...
5 million years ago, the site,
which was located in the crook of a river
course, was used for only a relatively short
period of time
...
Microscopic
patterns on stone-tool edges indicate their
use in cutting meat, soft plant material,
and wood
...
(Courtesy of A
...

Behrensmeyer
...
3 Excavation in progress: Site 50, on the eastern
shore of Lake Turkana, has yielded important information with
which to test the hypothesis that the co-occurrence of bones and
stones resulted from hominin activity
...
Geological analysis indicates that hydraulic processes probably had little or no influence in the formation of
most of the bed I sites
...

His conclusion was forthright: “The only clear picture obtained
is that of a hominid scavenging the kill and death sites of
other predator-scavengers for abandoned anatomical parts of
low food utility, primarily for purposes of extracting bone
marrow
...
”

Figure 26
...

(Courtesy of Glynn Isaac
...
No humanlike social

26: Hunter or Scavenger?

Owl

Scavengers
remove

nes

Chewing

Sto n

es

Breaking

o
Flo

ht

hin

nes
Bo

Hominid
carrying

g s I N and O

Cutting

Input

UT

Feeding

w
as

Carnivore
carrying
Bo

ds

Bon

es
Exit

Stones and
bon
es

Hominids
remove

Figure 26
...
Archeological excavations can recover only what
remains at a site and what can be preserved (bones and stones, not
plant and soft animal material)
...
)
Hypothesis X
Whole carcasses
Transport

Cache of stones
Hypothesis Y

173

implications can be made for such species
...

This last conclusion has also been reached by several
of Isaac’s associates, including Potts, Pat Shipman (of Pennsylvania State University), and Henry Bunn (of the University
of Wisconsin)
...
Specifically, none of the three
agrees with Binford that the accumulations are primarily the
result of carnivore activity
...
The assessments made by Potts, Bunn, and Shipman
differ in terms of how much of the accumulations are
attributed to hunting and how much to scavenging
...
For example, as Potts points out, this version of
residual analysis makes the a priori assumption that hominins
displayed no carnivore-like activity
...
Potts’ own analysis of the
Olduvai archeological sites indicates that the pattern of bone
accumulation is more diverse than would be expected at
exclusively carnivore sites
...
” Early scavenging could occur when, for example,
a hominin locates a dead animal that has not yet been partially eaten by a nonhuman carnivore
...
6 Rival hypotheses: Accumulation of stone artifacts
and broken animal bones in the same location form an important
element of the early archeological record
...
For
instance, hypothesis Y suggests that the accumulation occurs at one
location because hominins used trees there to escape competition
from other carnivores while eating scavenged meat
...
Both cases produce
the same result: an accumulation of bones and stones in one
location
...
)

In 1979, Potts, Shipman, and Bunn simultaneously discovered
cutmarks on fossil bones at Olduvai, which apparently had
been inflicted by stone flakes used to deflesh or disarticulate
the bones
...
(See figures 26
...
8
...

Shipman, for instance, sees little or no indication that the
Olduvai hominins were disarticulating bones and therefore
concludes that the bone accumulations were principally the
fruits of scavenging from other carnivore kills
...
Of the two, Bunn more strongly favors hunting as an
important aspect of the Olduvai hominins’ behavior
...
“To ask whether early
hominids were hunters or scavengers is therefore probably
not an appropriate question,” he says
...
7 Bone jigsaw puzzle: Fragments of bone found at
site 50 were conjoined, producing these two ends of the humerus of
a large, extinct antelope
...
Cutmarks were also
present on the bone
...
8 Cutmarks in closeup: This fragment of bone from
site 50 bears characteristic marks that are left when a stone tool is
used to deflesh a bone
...


Nevertheless, whether they were hunted or scavenged, the
remains of animals at the Olduvai sites could, in principle,
serve as an indication of hominin home bases
...
Typical hunter-gatherer home
bases are places of intense social activity and havens of safety
that are occupied for periods of a few weeks and then abandoned
...
The carnivores left their signatures on the sites in the form of tooth marks on certain bones
...
Other tooth marks are
overlapped by cutmarks, which appears to confirm that the
hominins occasionally scavenged from carnivore kills
...
This work was based on a comparison of tooth marks and percussion marks on fossil bones
from Olduvai with marks produced experimentally
...
Potts’ computer simulations appeared to
show that, on energetic grounds, forming stone caches and
bringing carcasses to them would be an optimal strategy
...

Some of this raw material was never processed, but was left
as lumps called manuports
...
Instead of home bases, these sites appear to have been
meat-processing and consumption places
...
For instance, some locations at Koobi
Fora, including site 50, are clearly not stone caches because
the stone artifact raw material is sourced on the spot
...
Whether this development represents
a change through timeasite 50 is approximately 300,000
years younger than the Olduvai sitesaor differences in ecological context remains unknown
...
“Conscious motivation for ‘sharing’ need
not have been involved,” he wrote in 1982
...
”
Here Isaac was touching on a difficult methodological issue
athat of trying to imagine the lives of humanlike creatures in
unhumanlike terms
...
Lacking weapons to kill at a distance, as humans did
until late in prehistory, hunters could achieve only very limited goals and might not qualify as hunters in the commonly
understood sense
...

It is worth noting the evidence, produced by Leslie Aiello,
for a change of body proportion between Australopithecus
and Homo that would be consistent with an adaptation for
great routine activity (see unit 24)
...
5 million years onward, plus shifts in dentition in Homo
(reduced posterior, increased anterior), it might signal a
significant shift in subsistence strategies
...

The discovery of wooden spears at the site of Schöningen
in Germany, dated about 400,000 years old, and their descriptions published in February 1997, implies that systematic
hunting had been well developed by that date
...
Human ancestors: changing views of their behavior
...

Blumenschine RJ
...

J Human Evol 1998;34:565–607
...
Percussion marks, tooth marks, and experimental determination of the timing of hominid and carnivore access to long
bones at FLK Zinjanthropus, Olduvai Gorge, Tanzania
...

Blumenschine RJ, Cavallo JA
...
Sci
Am Oct 1992:90–96
...
Systematic butchery by Plio/Pleistocene hominids
at Olduvai Gorge, Tanzania
...

Dennell R
...
Nature 1997;385:767–768
...
The behavioral ecology of hunter-gatherers, and
human evolution
...

Isaac G
...
World Archeol 1982;3:1–
87
...
Archeology and the evolution of human behavior
...

Lupo KD
...

J Archeol Sci 1994;21:827–837
...
A hypothesis to explain the role of meat-eating in human
evolution
...

O’Connell J, et al
...
J Human Evol 2000;38:A23–A24
...
Meat eating, hominid sociality, and home bases
...

Shipman P
...
Am Anthropol
1986;88:27–43
...
Early hominid hunting and scavenging: the role of meat as
an energy source
...


PART 7

THE ORIGIN
OF MODERN
HUMANS
27
28
29
30

The Neanderthal Enigma
Anatomical Evidence
Genetic Evidence
Archeological Evidence

27

THE
NEANDERTHAL
ENIGMA

Neanderthals were the first fossil humans to be discovered, in the
mid-nineteenth century
...
The relationship of Neanderthals has long been
debated
...


Neanderthals, everyone’s favorite “caveman,” lived in much of
Europe, part of Asia, and the Middle East between 150,000 to
probably just less than 30,000 years ago (these last occurrences
were observed in western Europe)
...
More bones of Neanderthals
are known than for any other fossil hominin group, including some 30 nearly complete skeletons, so this preoccupation
within the anthropological profession is understandable
...
1 Neanderthal anatomy
...
At
times, they have been viewed as the direct ancestors of modern Europeans; at other times, they have been regarded as a
side branch of the human evolutionary tree, with extinction
as their fate
...


Neanderthal anatomy
Neanderthal anatomy represents a mixture of primitive
characters, derived characters that are shared with other
hominins, and derived characters that are unique to Neanderthals (see figure 27
...
In general terms, Neanderthals

d
a
b
b
a
c
c

b

e

f

d
d

e

c

Primitive features

Shared, derived features

Unique, derived features

a
...
Well-developed supraorbital torus
c
...
Large dentition
e
...
Broad cranial base

a
...
Reduced occipital torus
c
...
Large brain
e
...
Spherical shape of cranial vault
(seen in rear view)
b
...
Teeth positioned forward
d
...
3 La Ferrassie: A 50,000-year-old Neanderthal from
the site of La Ferrassie, France, discovered in 1908
...
)

may be described as being robustly built, heavily muscled,
and short in stature
...
This structure implies that, whatever the details of Neanderthal subsistence, this species’ daily
life involved routine, heavy work
...
2 Skull shape: The triangle in
the Neanderthal skull (left) shows the spatial
relationships between the forward edge of
the first molar (C), the lower edge of the
cheek bone (A), and the upper edge of the
cheek bone (B)
...


consistent with life in a cold environment (Bergmann’s rule;
see unit 11), as are the short forearm and lower leg relative to
the humerus and femur (Allen’s rule; see unit 11)
...

An aspect of the skull anatomyathe extreme protrusion
of the upper faceahas also been speculated to be related to
cold adaptation
...
Now hold the nose and pull
it out several inches
...

Two bony projections jut into the front of the nasal cavity
from either side, an anatomical feature not seen in any other
hominins
...
2 and 27
...
)
Body weight for the Neanderthals is estimated at 63
...
67 meters for males and 1
...
Despite their short stature, Neanderthals had large
brains, an average of 1450 cubic centimetersasome 100 cubic
centimeters larger than the modern average
...

Inevitably, brain size impinges on the question of Neanderthals’ capacity for spoken language
...

These specimens share the overall shape of brains of earlier
humans, with the brain appearing low and broadest near
the base, with small frontal lobes and large occipital lobes (at
the back of the brain)
...
The hyoid attaches to the
base of the tongue, and thus is important in the mechanics of

27: The Neanderthal Enigma
verbalization
...
Evidence of limited verbal skills does appear in the
structure of the larynx, which is inferred from the shape of
the cranial base (see unit 32)
...
The canal is the hole through which nerve
fibers exit from the brain to the tongue
...
(The
canal is much smaller in other creatures
...
They
concluded that there was too much variation within and
between species for a sound conclusion to be drawn
...

The Neanderthal pelvis is unique
...
When a more complete specimen came to light in
1987 (from Kebara), it revealed that the pelvic canal is not
unusually largeajust that the pubic bone is extraordinarily
long
...
4 Mousterian tools: Neanderthals made stone tools
using the Levallois technique, which involves striking flakes from a
prepared core and then fashioning tools from the flakes
...


Neanderthal behavior
Neanderthals lived by hunting and gathering, probably in
small, nomadic groups, an existence that, judging from their
extremely robust anatomy and large muscle attachments,
evidently required extraordinary strength
...
For the Neanderthals, this
Middle Paleolithic technology is termed the Mousterian
technology, with the name being derived from a cave at Le
Moustier, France
...
4
...
Mousterian assemblages
show little use of bone, antler, or ivory
...

Known as the Chatelperronian, after a cave site near to
Chatelperron in France, this technology was long a mystery
to archeologists
...
5
...
In 1979, Neanderthal remains were found in
association with Chatelperronian tools at the cave site of
Saint-Césaire in France, which is dated at 36,000 years old
...
In this case, part of a
33,000-year-old temporal bone of a child was identified as
Neanderthal on the basis of the structure of the bony
labyrinth (inner ear), in which Neanderthals are derived
with respect to Homo erectus and modern humans
...
Upper Paleolithic technology first appeared in
western Europe 40,000 years ago; called the Aurignacian
(see unit 30), it represented the work of modern humans
...


182

Part Seven: The Origin of Modern Humans

Figure 27
...
(Courtesy of Ofar Bar-Yosef
...
5 Chatelperronian tools: Late in Neanderthal
history, populations in western Europe manufactured tools that
included many Upper Paleolithic elements, such as blades
...


Another tool that the Neanderthals used routinely was
their front teeth
...

Remains of Neanderthals have often been found in caves,
sometimes in circumstances suggesting deliberate burial, as
at the Kebara Cave in Israel, for example
...
6
...
And a
woman’s skeleton was also found in an exaggerated fetal
position in the cave of La Ferrassie
...

Some of the “burials” can probably be explained by natural
events, such as the collapse of cave roofs on occupants or
abandoned bodies, and thus are devoid of ritual
...
The evidence is convincing that Neanderthals, and probably other archaic sapiens, occasionally buried
their dead with a degree of ritual that we recognize as
human
...


Finally, there have been many tantalizing hints over the
years that Neanderthals practiced cannibalism
...
The bones of red deer and
Neanderthals in the same cave appear to have been handled
in identical fashion
...

“No mortuary practice has ever been shown to leave these
patterns on the resulting osteological assemblages
...


A brief history of discovery and
interpretation
In August 1856, quarry workers in the Neander Valley,
Germany, unearthed humanlike bones in a cave, Feldhofer
Grotto, above the Düssel River
...
Clearly the
remains of a bulky and powerfully muscled individual, they
were unlike anything Fuhlrott had seen before, so he sought
the more informed viewpoint of Hermann Schaaffhausen, a
professor of anatomy at the University of Bonn
...
William King, an Irish anatomist,

27: The Neanderthal Enigma
was unusual among his colleagues for regarding the Feldhofer
specimen as different from Homo sapiens, and in 1864 he gave
it the species name Homo neanderthalensis
...
More
important, Eugene Dubois’s discovery of Pithecanthropus in
the early 1890s forced serious consideration of what ancestral forms of human might have looked like (see unit 24)
...
Under this view, Neanderthals are usually given a subspecies attribution, Homo sapiens
neanderthalensis, while modern humans would be Homo
sapiens sapiens
...

The La Chapelle-aux-Saints Neanderthal was virtually
complete, offering anthropologists the first opportunity to
compare in detail Neanderthal anatomy with that of modern
humans
...
The picture Boule sketched of the
Old Man of La Chapelleaand by implication all Neanderthals
awas less than flattering
...
Very quickly the
anthropological establishment accepted Boule’s characterization of Neanderthals, and pronounced the species to be an
evolutionary specialization that went nowhere
...
7 and 27
...
)
Boule’s description of Neanderthals as an evolutionary
dead end left modern man without an ancestor
...
The so-called presapiens theory was developed at this point, which argued that
there had been an ancient split in the human lineage which
led to the early appearance of a relatively modern skeletal
form alongside a more archaic hominid, represented in the
fossil record by the Neanderthals
...
For
instance, the American anthropologist Ales Hrdlic tried,
ˇ
ˇka
but failed, to resurrect the unilinear hypothesis in the 1920s,
based on anatomical and archeological arguments
...
”

183

Figure 27
...
He
drew this famous comparison between the Neanderthal (left) and a
modern human
...
Later, the German anatomist Franz
Weidenreich (see unit 24) invoked these fossils in a sophisticated elaboration of Hrdlic
ˇka’s Neanderthal-phase hypothesis
...
Moreover, Weidenreich envisaged parallel evolutionary lineages

184

Part Seven: The Origin of Modern Humans

Figure 27
...


Figure 27
...


in various regions of the Old World, all leading through
separate Neanderthal-like stages to the modern geographical
variants of modern humans
...
This model, which was elaborated during
the 1940s, is the precursor to a major position in the current
debate (namely, the multiregional evolution model; see
unit 28)
...
Eventually, a confluence of events
through the 1940s, 1950s, and 1960s overturned the dominance of the pre-sapiens theory; instead, it became just one of
several competing theories, which included in their number
the unilinear model
...
The
second was the exposure of the Piltdown fossils as a hoax,
which removed this pillar of support in a single stroke
...

The rehabilitation of Neanderthal was effectively completed by Loring Brace, of the University of Michigan, whose
1964 paper, “The Fate of the ‘Classic’ Neanderthals,” was
highly influential
...
(See figure 27
...
) By the late 1960s,
Neanderthals had been restored, in many people’s eyes, to
their rightful place: as direct ancestors of modern humans
...

Brace added an extra stage to Schwalbe’s original, threestage scheme to transform it: australopithecines to pithecanthropines to Neanderthals to modern humans
...
10 Geographical distribution: Neanderthal populations were confined to Europe, the Middle East, and western Asia
...
)

Montmaurin

0

Wadi Halfa

EGYPT

Qafzeh

BLACK SEA

Kiik-Koba
Staroselye

Do

D
RE

Hortus

Fontéchevade La Chapelleaux-Saints
La Chaise
Regourdou
La Quina
Pech-de-l’Azè
La Micoque
Cro-Magnon
La Ferrassie
La Borde
Grotte Vautrey
Combe-Grenal

ˆ
Chateiperron

MED
ITERR
ANEA
N SEA

Petralona

Bacho Kiro

BALKANS

r

est

Dn

e

FRANCE

NORTH AFRICA

Arago Terra
Amata
ITALY
Saccopasfore
Monte Circeo (Guattan)
Sant’ Agostino

Vertesszõffõs Erd
Vindija
Dan
Krapina
ube

Ganovcé
Molodova

Middle Pleistocene
glacial maximum

SP

St Césaire

IBERIA

SEE INSET

Alps

Tata

Late Pleistocene
glacial maximum

40°

is

30°

High Lodge

20°

Tigr

Dar-es-Soltan
Jebel Irhoud

Hoxne

NORTH
SEA

0°

Feldhofer
Clacton
Swanscombe Cave
Salzgitter Lebenstedt
Boxgrove
Engis
Bilzingsieben
Blache-St-Vaast
Maastricht- Ehringsdorf
La Cotte
Spy Belvédere
Lavallois
Mauer
Bockstein & Stadel
Arcy-sur-Cure
Steinheim

Paviland

Pontyprydd

El Casillo
Cuewe Monn
Atapuerca

Vilas Ruivas

ATLANTIC OCEAN

50°

20°

CA

A
SE

186

Part Seven: The Origin of Modern Humans

the ultimate expression of the unilinear pattern (see unit 3)
...
In the mid-1970s, the discovery
of the coexistence at Koobi Fora of a small-brained, highly
robust individual (KNM-ER 406, Australopithecus boisei ) and a
large-brained, nonrobust individual (KNM-ER 3733, Homo
ergaster) demonstrated that the single-species hypothesis was
invalid, at least for that period of human prehistory (close to
2 million years ago)
...
A scientific tradition carrying the names of
Schaaffhausen, Schwalbe, Hrdlic
ˇka, Weidenreich, and Brace
is therefore continued by Wolpoff
...
(See figure 27
...
)

Implications of Neanderthal DNA
One of the more dramatic developments in the study of
Neanderthal prehistory came in mid-1997, with the report of
the extraction of mitochondrial DNA from the fossilized
bones of the type specimen, discovered in the Neander Valley
in 1856
...
For
instance, the average number of nucleotide differences in
this sequence among modern humans is eight; by contrast,
the Neanderthal sequence differed in 28 nucleotide positions,
implying that it was genetically very distant from modern
humans, and could not have been ancestral to them
...
Further reports of comparisons of
Neanderthal and modern human DNA have strengthened
the original conclusion
...


KEY QUESTIONS
• What aspects of Neanderthal anatomy imply an adaptation to
cold environments?
• What is the most likely origin of the Chatelperronian tool industry?
• Why did so much resistance arise against accepting Neanderthals
as a form of ancient human when they were first discovered?
• How is the current taxonomic status of Neanderthals best
described?

KEY REFERENCES
Beerli P, Edwards SV
...
1):60–68
...
Hypoglossal canal size and hominid speech
...

Gargett R
...

Curr Anthropol 1989;30:157–177
...
A late Neanderthal associated with Upper Paleolithic
artifacts
...

Kay R
...
Proc Natl Acad Sci USA 1998;95:5417–5419
...
Neanderthals and modern humans in West Asia
...

Krings M, et al
...
Cell 1997;90:19–30
...
A view of Neanderthal genetic diversity
...

Orchinnikov IV
...
Nature 2000;404:490–493
...
Significance of some previously unrecognized apomorphies in the nasal region of Homo neanderthalensis
...

Shea JJ
...
Evol Anthropol 2003;12:173–197
...
The Neanderthals: evolutionary dead ends or ancestors of
modern people? J Anthropol Res 1991;47:219–238
...
The Neanderthals and their evolutionary significance: a
brief historical survey
...
The origins of
modern humans
...
Liss, 1984:1–49
...
New perspectives on the Neanderthals
...
1):58–63
...
In search of the Neanderthals
...

Tattersall I
...
New York: Macmillan, 1995
...
Hominids and hybrids: the place of
Neanderthals in human evolution
...

Trinkaus E, Shipman P
...
New York: Alfred A
...

White T
...
Sci Am 2001;265:58–65
...
Each has very
different predictions about what is expected to be seen in the fossil
record
...


Since the 1980s, the question of the origin of anatomically
modern humans has been among the most hotly debated
issues in paleoanthropology, with very divergent opinions
being vigorously expressed
...
In this view,
the genetic roots of modern geographical populations of
Homo sapiens are deep, reaching back to the earliest populations of Homo erectus as they became established throughout
much of the Old World (almost 2 million years in some
cases)
...

In this scenario, the genetic roots of modern geographical
populations of Homo sapiens are very shallow, going back perhaps 100,000 years
...


Competing hypotheses
The multiple-origins, or multiregional, hypothesis was the
first comprehensive theory of the origin of modern humans
...
This hypothesis attempts to explain
not only the origin of Homo sapiens, but also the existence
of anatomical diversity in modern geographical populations
...
This persistence is
known as regional continuity
...
It has since been modified, with gene
flow between populations now viewed as an important component
...
It views the erectus-to-sapiens transformation as
a balance between the maintenance of distinctive regional
traits in anatomy through partial population isolation and
the maintenance of a genetically coherent network of populations throughout the Old World through significant gene
flow
...
1b
...

Leakey considered the Early and Middle Pleistocene hominins
of Africa to be better candidates for modern human ancestry
than the Homo erectus fossils of Asia; the latter, he said, were an
evolutionary dead end
...
W
...
The most extreme form
of this recent African origin (or out of Africa) hypothesis,
which assumes substantial replacement of archaic populations by invading modern humans, is most closely associated
with Chris Stringer, of the Natural History Museum, London
...
The hypothesis views the establishment of
regional anatomical traits in today’s geographic populations
as the result of adaptation and genetic drift in local populations during the last 100,000 years
...
1a
...

The two fundamental questions in testing the hypotheses
against the fossil record are the location of the earliest anatomically modern humans and the issue of regional continuity
...


Where were the earliest anatomically
modern humans?

Figure 28
...

(b) The multiregional evolution model, which balances gene flow
between separate geographical populations and maintenance of
regional anatomical integrity
...
For the extreme hypotheses, the predictions are as
follows
...

In the multiregional evolution model, three expectations
follow:
• Anatomically modern humans will appear throughout the
Old World during a broadly similar period, although one area
might see such populations earlier than the rest;
• Transitional fossils, from archaic to early modern anatomy,
should be found in all parts of the Old World; and
• In each region of the Old World, continuity of anatomy
from ancient to modern populations should be apparent
...
Nevertheless, these people
were still more robust than modern-day humans
...

Specimens of anatomically modern humans from Africa
and the Middle East stand out as significantly older than
those seen elsewhere in the Old World
...
(A
second brain case, Omo 2 (Kibish) is slightly more primitive,
but roughly the same age
...

The dates for these fossils range between 70,000 and 120,000
years old
...
Provenance has been a concern in these
cases, so that the true date may be substantially less than
100,000 years
...
Most anthropologists judge these specimens to
be essentially modern, even though they have some archaic
features
...
Elsewhere in the
Old World, the earliest modern remains come from the cave
site of Liujiang, in southern China, with a date of 67,000
years, but possibly younger
...

Similarly, the earliest modern people in Europe are latecomers, appearing some 40,000 years ago
...
(See figure
28
...
)
Prior to the discovery of the new Ethiopian fossils, the
roughly similar dates of the African and Middle Eastern

28: Anatomical Evidence

189

30K(?)
50K

1
...
7M
35K

1M
60K

100K

60K
1
...
2 Two migrations: If the single, recent-origin model
is correct, then the original expansion of Homo erectus from Africa
into the rest of the Old World would have been followed much later
by a similar expansion of modern people
...
In fact, multiple population movements must have occurred
at different times and in different places
...


fossils led some anthropologists to suggest a North African
origin for modern humans, with the Middle East as part of
the same ecological zone
...
The strikingly
modern form of the Omo 1 (Kibish) brain case dated at as
much as 130,000 years old, and the 160,000-year-old Herto
fossils, described in June 2003, provide sub-Saharan Africa’s
strongest claim to being the region of origin
...
3
...
The identification of such putative
regional continuity in the Far East, in fact, led Weidenreich
to formulate the multiregional hypothesis half a century ago
...
The issue of regional continuity remains the
most contentious aspect of the current debate, however,
with little agreement between proponents of competing
hypotheses over interpretation of relevant fossil anatomy in
these geographical regions
...
The extreme form of the

Australasia
Proponents of multiregionalism argue that Australasia offers

190 Part Seven: The Origin of Modern Humans
Mauer (500k)

Steinheim (250k)

Area of classic (i
...
true)
Neanderthals (150–35k)

Swanscombe (250k)

Boxgrove (500k)
(30k) Cro-Magnon

Zoukoutien
(500–200k)

(350–400k) Arago
Upper Cave (20k)
Jinniu Shan (200k)

(150k) Jebel Irhoud

Dali (200k)
(100k) Skhul
(100k) Qafzeh
(60k) Kebara
(60k) Amud
(120k) Tabun

Herto (160k)
Bodo (300k)
Singa (150k)

Ngandong (55k)

Omo (130k)
Koobi Fora (100k)

Elandsfontein (300k)

Maba (130k)

Sangiran (1
...
3 Map showing some of the most important
sites
...
The argument is based on essentially three data
points: the earliest inhabitants of Java, much more recent
archaic forms in Java, and modern Australians
...
Their foreheads were flat and retreating, and the large, projecting faces
sported massive cheek bones
...
As noted in unit 24, these people may
have lived in Java as long as 1
...

The next data point is taken from a dozen brain cases
found in 1936 at Ngandong, in western Java
...
Multiregionalists see them as descendants of
the earlier Javan Homo erectus people, displaying many of the
same anatomical features mentioned above, but with
enlarged brain cases
...
Until recently, they had been estimated to have been
more than 100,000 years old, but dates newly obtained at the

Berkeley Geochronology Center place them between 27,000
and 53,000 years old
...
This
development is parallel to the situation in Europe, where
Neanderthals and modern humans coexisted for a while
...
Archeological evidence indicates that humans
first reached Australia approximately 60,000 years ago,
although fossil evidence is considerably younger (see unit
34)
...
”
Can the features cited as evidence of regional continuity
truly be traced from ancient Javan Homo erectus (1
...
More particularly, are these features truly unique
(that is, derived) to this region of the world?
A general anatomical similarity undoubtedly exists in
these three populations, particularly in terms of their robusticity
...
4 Chinese fossils: (a) The
Lantian cranium (Homo erectus)
...
Scale bars are 1 cm
...
Two independent studies by Australian
anthropologists Colin Groves and Phillip Habgood in the
late 1980s, however, questioned the phylogenetic validity of
several of these features, concluding that they are retained
primitive traits common to Homo erectus and archaic Homo
sapiens, not derived features unique to the region
...
More recently, Marta Lahr, of Cambridge
University, England, reached similar conclusions based on
an examination of cranial features
...
” This ambiguity
does not disprove continuity, she noted, but merely indicates
that the evidence currently adduced in its support is invalid
...
As Aiello observed, it “was characterized by a complicated mosaic of gene flow, population migration, and continuity throughout the Middle and Late Pleistocene periods
and
...
” The bottom line, then, is that
neither hypothesis is strongly supported or disproved in
Australasia
...
Although the East
Asian fossil record is richer than that of the Far East, this
statement is surely an exaggeration
...
”
The earliest known human fossil material in the region
consists of a cranium from Lantian, in northeastern China;
this Homo erectus specimen is dated at close to 1 million years
...
4
...
Homo erectus remains of
similar age to the youngest fossil at Zoukoutien have also
been found at Hexian
...
These latter two
specimens are generally known as archaic sapiens, and in the
multiregionalists’ scheme they represent forms transitional
from erectus to modern Homo sapiens
...


192

Part Seven: The Origin of Modern Humans

This picture became more complicated in the early 1990s,
after the discovery of two crushed crania at Yunxian, in eastcentral China
...
If their anatomical attribution and age are
correct, they would be almost twice as old as some of the
latest Homo erectus populations, undermining the pattern of
regional transition as envisaged in the multiregional evolution hypothesis
...
Eastern Asians, both ancient and
modern, have smaller faces and teeth, flatter cheeks, and
rounder foreheads; their noses are less prominent and are
flattened on top
...
Critics of multiregionalism point out that this supposed derived feature is also found in ancient populations
elsewhere in the Old World, and therefore cannot be used to
link Chinese Homo erectus to modern Chinese people
...
Moreover, a study
by J
...

In Aiello’s view, the evolutionary history of the region was
complex, and neither the multiregional nor the single-origin
hypotheses is strongly supported or refuted in East Asia
...
The first excavations began in the 1930s at
the cave sites of Skhul and Tab¯ on Mount Carmel, Israel,
¯
un
and produced partial skeletons that probably resulted from
deliberate burial
...
5 and 28
...
) The Tabun
¯
individuals are Neanderthals, while those from Skhul are
¯
primitive-looking moderns
...
5 Middle Eastern moderns:
Crania from (a) Skhu and (b) Qafzeh
...
Scale bars are 1 cm
...
6 Middle Eastern
Neanderthals: Crania from (a) Tabun
¯
and (b) Amud
...
Although
the Tabu people predated the moderns,
¯n
those from Amud did not, making such a
relationship impossible
...


(b)

near the Sea of Galilee; and Qafzeh, near Nazareth)
...

Until a decade ago, the Neanderthals were thought to predate the modern population (with ages of 60,000 and 40,000
years old, respectively) and were assumed to be ancestral to
them, in line with the multiregional hypothesis
...
Kebara and Amud appear to be nearly 60,000
years old, as believed earlier, but Tabun is much older at
¯
approximately 120,000 years
...
Clearly, a simple ancestor–
descendant relationship between Neanderthals and moderns
is not possible, as the moderns are near-contemporaries with
the earliest Neanderthals of the region, and Neanderthals
persist for at least 40,000 years after the first appearance of
moderns
...
7
...
The body proportions of the modern people
more closely resemble those of warm-adapted Africans than
those of cold-adapted Neanderthals (see unit 11), which provides additional support for the single-origin hypothesis
...
(The fact that the two populations used identical
stone-tool technologies, the Mousterian, is adduced in support of this notion; see unit 30
...
Moreover, aspects of the Neanderthal
postcranial anatomy show retention of certain primitive
features (in the femur and pelvis) that the moderns lack
...

Europe
The Middle to Late Pleistocene hominin fossil record of
Europe is dominated by the Neanderthals (see unit 27)
...
According to the multiregional
evolution hypothesis, the Neanderthals were part of a gradually evolving lineage that eventually yielded anatomically
modern humans in Europe
...

As noted in unit 24, no unequivocal fossil evidence exists to
prove the presence of Homo erectus in Europe
...

These remains of many individuals include some that may be
780,000 years old
...
However, in May 1997, the
discoverers of the Spanish fossils elected to name them a new
species Homo antecessor
...

The Mauer mandible, found in 1907 and dated at roughly
500,000 years old, combines primitive features (robusticity)
with modern features (molar size)
...
(See figure 28
...
) Other
fossils with a similar mix of ancient and modern were found
in the mid-1930s, such as a cranium at Steinheim, Germany,
and skull fragments at Swanscombe, England
...
The
Steinheim skull possesses heavy brow ridges and a low fore-

Tabun

Figure 28
...
More
recent dating efforts have complicated that
simple picture
...

In 1960, Greece joined in the panoply of European archaic
human sites, with the discovery of a robust but large cranium
in a cave at Petralona
...
(See figure 28
...
) In the early 1970s, the face, forehead, and two jaws of an archaic form were found at the
cave of Arago, near Tautavel, in southwest France
...

Overall, the Arago fossil is more primitive than the Steinheim
model, and perhaps 100,000 years older
...
Its age has been estimated at
500,000 years, or similar to that of the Mauer mandible
...
In
1993, a team of Spanish researchers reported the discovery
of 1300 human fossil remains (representing 30 individuals)
from a single site (Sima de los Huesos), dated at close to
300,000 years old
...
Like other
human fossils of this age in Europe, the specimens display a

28: Anatomical Evidence

195

(a)

Figure 28
...
It is dated at
500,000 years and is the type specimen of
Homo heidelbergensis
...
Scale bars
are 1 cm
...
9 The Petralona cranium:
Found in 1960, the cranium is robust but
has a large brain case, thus combining
archaic and modern features
...
Scale bars
are 1 cm
...
However, in 1997, the
fossils’ discoverers elected to name them a new species, Homo
antecessor
...

antecessor is evidence of a gradual transition to Homo sapiens
...
heidelbergensis, but had nothing to do with the ancestry
of Homo sapiens
...
What of their fate? Beginning some 40,000

years ago, classic Neanderthal anatomy disappears in Europe,
with an east-to-west progression that ends nearly 27,000
years ago
...
Fossil evidence indicating
the presence of anatomically modern humans follows the
same trajectory
...
A frontal bone with a high forehead and small
brow ridges has been found at Velíka Pec
˘ina in Croatia and
dated at 34,000 years
...
10 Cro-Magnon: The famous
cranium from Les Ezyies, in France, dated at
30,000 years, provides an example of early
modern people in western Europe
...

Nerve

Figure 28
...

Multiregionalists argue that early modern
people in Europe also had a high incidence
of the bony ridge, indicating important
morphological continuity
...
A large collection of somewhat
robust modern human remains was found at Mladec
˘,
Czechoslovakia
...
(See
figure 28
...
)
When Bräuer and his colleague K
...
Rimbach compared
the crania of the early moderns of Europe, the early moderns
of Africa, and the Neanderthals, they found a close morphological similarity between the first two but saw no link
between early European moderns and Neanderthals
...

This character may be taken as strong evidence of the
replacement of Neanderthals and supports the single, Africanorigin hypothesis
...
As evidence, they adduce
the size of the nose in Neanderthals and later Europeans,
some details of the back of the skull, and, most particularly,
the shape of the mandibular nerve canal
...
11
...

The incidence in later, modern Europeans is just 6 percent
...
Stringer and

Bräuer have recently criticized this claim, saying that while it
might indicate gene flow between Neanderthals and early
moderns, it is just as likely to be a statistical fluke
...
Given the small sample size of just three individuals, the inclusion of just one with an infrequent feature
would produce an erroneously high incidence
...

Aiello’s assessment is that the anatomical (and archeological) data of Europe “do not contradict an ultimate African
origin for modern humans; however, they also do not clearly
substantiate this hypothesis
...
The first find was made in 1921 at a cave site at
Kabwe (formerly Broken Hill), Zambia (see figure 28
...

The specimen, a cranium, was originally called Rhodesian
Man, but is now more generally referred to as the Kabwe cranium
...
12 The Kabwe cranium:
Estimated to be at least 200,000 years old,
this cranium was the first early human fossil
found in Africa
...


Figure 28
...
The species
name of Homo helmei would be appropriate
for this specimen, if a specific designation is
justified
...


brow ridges reminiscent of Neanderthals
...
The specimen’s age is estimated to be at
least 200,000 years
...
The cranial
shape of most of these African archaics is long, as in Homo
erectus, but more elevated; from the rear, it appears to be
wider at the top than at the base, unlike the structure in
Homo erectus
...

In northern Africa, archaic forms of Middle Pleistocene
age have been found at Salé and the Thomas Quarries, in
Morocco
...
The species is held to be ancestral to modern
humans, through a form represented by several specimens
that are generally modern, but not yet fully modern
...
13)
...
Recent dating of the
Florisbad cranium indicates that it may be as old as 300,000
years
...
In any case, these individuals could represent a form transitional to modern humans,
such as those found at Omo 1 (Kibish), Klasies River Mouth,
and Border Cave
...

This pattern of transitional forms from archaic to modern
fits both the single-origin and multiregional evolution hypotheses, of course
...
In
addition, the anatomical similarities between some of these
African archaic forms and archaics elsewhere in the Old
World support the single, African-origin hypothesis rather
than the multiregional evolution hypothesis
...
Lahr and her
colleague Robert Foley have argued that multiple dispersals

198
Age
(myr)

Part Seven: The Origin of Modern Humans
Europe & West Asia

Africa

East Asia

0
H
...
neanderthalensis
(H
...
5

H
...
0

1
...
0

H
...
ergaster

from a variable source population in Africa at different times
and via different routes may help explain how morphological
variability developed in the modern world
...
(See figure 28
...
)

KEY QUESTIONS
• How has the history of the interpretation of Neanderthals’ place
in human evolution influenced the modern debate over the origin of
modern humans?
• Why is the same fossil evidence often interpreted differently by
different anthropologists?
• What is the strongest evidence in favor of (1) the multiregional
evolution hypothesis and (2) the single-origin hypothesis?
• What additional fossil evidence would help to resolve the current
debate?

KEY REFERENCES
Aiello LC
...
Am Anthropol 1993;95:73–96
...
Late Pleistocene human population bottlenecks,

Figure 28
...


volcanic winter, and differentiation of modern humans
...

Bar-Yosef O, Vandermeersch B
...
Sci
Am April 1993:64–70
...
A hominid from the Lower Pleistocene
of Atapuerca, Spain: possible ancestor to Neanderthals and modern humans
...

Frayer DW, et al
...
Am Anthropol 1993;95:14–50
...
Some thoughts on the study and interpretation of the
human fossil record
...
, eds
...
San Francisco: California Academy of Sciences,
Memoir 21, 1996:1–38
...
The multiregional model of modern human origins
...

Lahr MM, Foley R
...

Evol Anthropol 1994;3:48–60
...
Research on the origin of modern
humans continues to dominate paleoanthropology
...

Nitecki M, Nitecki D, eds
...

New York: Plenum Press, 1994
...
Deep roots for the Neanderthals
...

Ruff CB, et al
...

Nature 1997;387:173–176
...
The emergence of modern humans
...

———
...
Nature 2003;423:692–
695
...
Latest Homo erectus of Java: potential contemporaneity with H
...
Science 1996;274:1870–
1874
...
Out of Africa again
...

Thorne AG, Wolpoff MH
...

Sci Am April 1992:76–83
...
Pleistocene Homo sapiens from Middle Awash, Ethiopia
...

Wolpoff MH, et al
...
Am J Physical
Anthropol 2000;112:129–136
...
In the two
decades of work on this topic, two things have become clear
...

Second, the picture that emerges from several realms of genetic analysis shows the pattern of origin and dispersal of modern humans was
probably more complex than is inferred from anatomical evidence
...


The first application of genetic data to the question of the
origin of modern humans took place in the early 1980s, but
not until 1987 did it become highly visible in this realm
...
It inspired the so-called mitochondrial Eve
hypothesis, which posited that the mitochondrial DNA in
all living people could be traced back to a single female who
lived in Africa approximately 200,000 years ago (hence the
inclusion of the term “Eve”)
...
Thus, the mitochondrial
Eve hypothesis was consistent with the recent, single-origin
(out of Africa) model and gave no support for the multiregional evolution model (see unit 28)
...
Recent work has concentrated on two lines
of inquiry
...
Second, genetic data have been used
to infer the population dynamics of early populations of
modern humans
...


The mitochondrial Eve story:
briefly told
Most of the DNA in our cells is packaged within the 23 pairs
of chromosomes in the nucleus, which in total measures
about 3 billion base pairs in length; this structure is known
as the nuclear genome
...
Mitochondria are the organelles
responsible for the cell’s energy metabolism, and each cell
contains several hundred of these structures
...
1
...
First, the DNA, which
codes for 37 genes, accumulates mutations on average 10
times faster than occurs in nuclear DNA
...
As mutations represent the equivalent
of information, mitochondrial DNA provides more information over the short term than does nuclear DNA
...
Because of this maternal mode of inheritance, no recombination of maternal and paternal genes
occurs; such a mixture may sometimes blur the history of the
genome as read by geneticists
...

One of the first significant observations to emerge from
this work was that the amount of variation of mitochondrial
DNA types in the modern human population throughout the
world is surprisingly lowajust one-tenth of that known
among chimpanzees, for instance
...
A calculation based

29: Genetic Evidence

201

Ovum

Fertilized ovum,
with mother’s
mitochondria
Offspring – male
and female –
with mother’s
mitochondria

Mitochondria

Figure 29
...
When the sperm fertilizes the
egg, it leaves behind all of its mitochondria;
the developing fetus therefore inherits
mitochondria only from the mother’s egg
...

An alternative explanation holds that modern humans
passed through a population bottleneck recently, which
reduced genetic variation
...
Another scenario
would involve the evolution of modern humans in ancient
times, followed by a recent population bottleneck
...
2
...
This discovery was taken to indicate that this population was oldest, and therefore represented the population
of origin of modern humans
...

Colorful though it is, the term “Eve” in the hypothesis title
is misleading, and it originally led to widespread misunderstanding of the implication of the study
...
This process is best explained by analogy
...
As time passes, the population remains stable (each
couple produces only two offspring)
...
If family names are passed only through males, onefourth of the family names will be lost in the first generation
...
After approximately 10,000 generations (twice the number of original females), only one family
name will remain (see figure 29
...
The same pattern holds
for the loss of mitochondrial DNA types, except that the
transmission flows through the female line
...
Two conclusions stand out
...
Second, in the more than 5000 individual
samples tested to date, not a single example of an ancient
(that is, deriving from a deep Homo erectus lineage) mitochondrial DNA has been detected, which is contrary to what
would be expected if the multiregional evolution hypothesis
were correct
...


A spectrum of genetic evidence
The multiregional hypothesis suggests that the roots of all
modern human populations go back to Homo erectus, which

202

Part Seven: The Origin of Modern Humans
*

70

15

60
*

14
13
12

80 *

11

50

f

10
9

g

8

e

7
90

6
40
d

4

h

3
2

Africa
100

5

Asia

30
*

Australia

1
0

New Guinea
Europe

c

One mother

110
20
i
*
*

b

120
j

10

a
Ancestor

130
1

*
0

0
...
4

0
...
6

0
...
2

0

Sequence divergence (%)

Figure 29
...
The
tree shows a split between African and non-African populations
...
The different degrees of
sequence divergence among the non-African populations give some
indication of when different parts of the Old World were colonized
...
(Courtesy of Rebecca L
...
Nature
...
By
contrast, the single-origin hypothesis states that modern
humans originated less than 200,000 years ago, probably in
Africa
...
3 Life of a lucky mother: An illustration of the
concept that all maternal lineages in a population trace back to a
single lineage in an ancestral population
...
The mitochondrial lineages of mothers bearing
only male offspring will come to an end, leading eventually to
one lineage dominating the entire population
...
)

cannot differentiate between the hypotheses, because both
claim an African origin
...
The question is, How can the molecular data best be used to test the two hypotheses in terms of
time of origin?
As we saw in unit 4, many genes accumulate mutations at
a rather regular rate, giving a potential molecular clock
...
This
ancestral type is known as the coalescent, and the time in
history at which it is reached is called the coalescence time
...
In other words, the gene tree is the
same as the population (or species) tree (see unit 8)
...
In this case, the coalescence time
predates the time of the origin of the species
...
5 Coalescence times and the origin of modern
humans: If modern humans originated close to 250,000 years ago,
as implied by the mitochondrial DNA hypothesis, then the
distribution of coalescence times would show a peak at that time
(top)
...
8 million years ago
(bottom)
...
)

Homo erectus
out of Africa

1
million years

II
C

0

1,

ap
o

-g

lo

bi

n

2
million years

ψη

n

3
million years

bi
glo
δ-

circumstances, the coalescence time may be younger
...
4
...
Some will coincide with
the age of the species; many will be slightly older; some will
be very much older; and a small number will be younger
...
If the multiregional model is correct, then those times should cluster
around 1
...
(See figure 29
...
) Ruvolo points out that, because
only the distribution of coalescence times is informative, a
single coalescence time cannot prove or disprove either
hypothesis
...

In the initial research, 14 coalescence times were calculated for various genetic loci, including 4 different measures
in mitochondrial DNA and 10 in different genes in nuclear
DNA
...
5, 1
...
3, 3
...
(Two independent studies on different regions of the Y chromosome, the
male equivalent of mitochondrial DNA, gave coalescence

1
...
4 Method of testing a hypothesis: When a
population splits, it leads to a distribution of coalescence times from
many genes (denoted as G1, G2, and so on)
...
No
single coalescence time is a reliable indicator because some genes
will have an older coalescence time than the population split, while
others will be younger
...
)

Mitochondrial DNA
Y chromosome
Protein polymorphisms
Microsatellites (chr 13,15)
Microsatellites/Alu (chr 12)

Figure 29
...
(Courtesy of Maryellen
Ruvolo
...
) (See figure 29
...
)
Remember that clustering of coalescence times is the most
important criterionanot the position of individual times
...

Genetic data used in human origin analyses include two
types that are particularly interesting: one is derived from
microsatellite DNA and the other involves so-called Alu
sequences
...
The results of

204 Part Seven: The Origin of Modern Humans
analyses of microsatellites and Alu sequences appear to support the recent, single-origin model
...
Unlike the rates of mutation for most
genetic elements, which often must be calculated by calibration against the fossil record, the rate of mutation of
microsatellites can be determined by laboratory observation
...

Alu elements are sequences of DNA approximately 300
base pairs in length, which become inserted in large numbers
over the nuclear genome
...
A recent, multiauthored study
on Alu elements in a large sample from around the world
gave a coalescence time of 102,000 years
...

In particular, population history may influence coalescence
times in ways unrelated to the establishment of a species,
usually leading to an erroneously young date
...
For example, population
crashes and explosions would affect mitochondrial DNA
variation to a greater extent than nuclear DNA variation
...
As
always, more data are required
...


A SECOND PATH OF INVESTIGATION:
POPULATION HISTORY
Two factors play into the new line of investigation followed
in population history analyses
...
The
low phylogenetic resolution in the data prompted certain
researchers to seek other kinds of information that might be
inferred from them, using a technique known as mismatch
distribution
...
(See figure 29
...
)

The conclusion of this work is that, early in their history,
the population of modern humans suffered a relatively
severe bottleneck
...
These data imply that the multiregional evolution model cannot explain modern human
origins
...

Henry Harpending and his colleague Alan Rogers, of the
University of Utah, developed a hypothetical model of a population that expanded within a brief period of time
...
(See figure 29
...
)
In their model, Harpending and Rogers assumed that
mutations accumulate regularly in all lineages (mutations
are shown as crosses on the horizontal lines in the middle
panel of figure 29
...
They then compared DNA sequences
between all pairs of lineages in a sample of this population,
and counted the number of mutational differences between
each pair (a sample of 50 individuals gives 435 pairs for comparison)
...
The rate at which mutations accumulate is
determined by both the rate of mutation at all sites in the
DNA and the generation time
...

Because the population underwent expansion at seven
mutational units of time in the past, a large proportion of
lineages in the current population will include seven mutational differences between them
...
When all pairs of lineages
have been compared and mutational differences counted,
these numbers are then arrayed on a histogram, with the
horizontal axis representing the mutational time, going from
zero in the present to ever-increasing numbers as one moves
back in time
...
7)
...
The position of the
crest of the wave indicates when population expansion
occurred; the shape of the wave shows its magnitude (the
sharper the peak, the more rapid was the expansion)
...
This discovery implies that the modern
human population underwent a rapid expansion of num-

29: Genetic Evidence

205

Effective
population size

500
Population
size
2uNF

1

0

7

14

Mutational time before present

Figure 29
...
(See text for details
...
)

Frequency of pair-wise
differences

Genealogy

Mismatch
distribution

0
...
10
Fi
0
...
00

0

bers, the timing of which was centered around 60,000 years
ago
...
The
African population expanded first, followed later by expansions in the European and Asian populations
...

Several possible scenarios exist to explain what happened
here, the most persuasive of which is the weak Garden of
Eden hypothesis
...
This concept is also called the Garden
of Eden hypothesis
...
According to this
hypothesis, once established (some 100,000 years ago), the

7

14

Site differences

founding population of modern humans fragmented into
separate populations; these groups later spread out geographically to form the modern populations of Africa, Europe, and
Asia
...
Thus, replacement
of archaic sapiens populations would still have occurred, but
would not have involved the same dynamics as envisaged
with the original Garden of Eden hypothesis
...
8
...
Several questions
arise here, the most important of which is, What was the
severity of the bottleneck?
The complicated calculation required to answer this question is based on the current genetic diversity of mitochondrial

206

Part Seven: The Origin of Modern Humans
African

Further global
expansion

Asian and European
populations expand
55,000
years ago

European

Asian

Origin of
modern humans

African
populations
expand 65,000
years ago

Population
fragmentation

ProtoEuropean
100,000+
years ago

Population
bottleneck

ProtoAfrican

ProtoAsian

100,000+
years ago

DNA in the world and on the mutation rate of these DNA
sequences
...
(Similar numbers
have been obtained from other data, including nuclear
DNA data
...
This figure creates a fatal problem for
the hypothesis because, as Harpending and Rogers note, “It is
difficult to imagine that a population this small could have
populated all of Europe, Africa, and Asia
...
too small to have populated three continents
...
Some
form of a recent, single-origin model would seem much more
reasonable
...
Louis, has analyzed 11 different human genes in populations in the Old World
...
But he
also identifies two major population expansions from that
continent after the expansion of Homo erectus
...

This, and other work, shows that the picture of human history at this stage was more complex than had been thought
...


~70,000
years ago

Figure 29
...
It posits the origin
of modern humans in Africa, prior to
100,000 years ago
...
A
population bottleneck reduced population
size, and genetic variation within them
...
Population
expansion then continued
...
The myth of Eve: molecular biology and human origins
...

Cann RL
...
Nature 2002;416:32–33
...
HLA sequence polymorphism and the origin of modern humans
...

Gibbons A
...
Science
1995;267:35–36
...
Y chromosome shows that Adam was an African
...

———
...
Science 1998;279:28–29
...
Genetic absolute dating based on microsatellites
and the origin of modern humans
...

Hammer MF, Zegura SL
...
Evol Anthropol 1996;5:116–134
...
Genetic traces of ancient demography
...

Harris EE, Hey J
...


29: Genetic Evidence
Krings M, et al
...
Cell 1997;90:19–30
...
Genetic admixture in the late
Pleistocene
...

Pritchard JK, Feldman MW
...
Science 1996;274:1548–1549
...
Genetic evidence on modern human origins
...

Ruvolo M
...
Mol
Phylogen Evol 1996;5:202–219
...
DNA and recent human evolution
...


207

———
...
Am
Anthropol 1994;96:131–141
...
A genetic perspective on the origin and history of
humans
...

Templeton AR
...
Am Anthropol 1993;95:51–72
...
“Eve”: hypothesis compatibility versus hypothesis testing
...

———
...
Nature 2000;416:45–51
...
Global patterns of linkage disequilibrium at the CD4
locus and modern human origins
...

Wilson AC, Cann RL
...
Sci Am
April 1992:68–73
...
Here, we explore the archeological evidence of the
behavior of the earliest Homo sapiens, to see how it meshes with the
other evidence
...

Recent evidence is beginning to question this scenario
...

For instance, while more than 100 sites dating between
250,000 and 40,000 years old have been carefully excavated
in southwestern France (and many more are known in less
detail), only about a dozen such sites have been studied in
East Africa, a region almost 100 times larger in geographical
extent
...
Several important discoveries have been made in Africa in recent years, however,
and their interpretation is leading some archeologists to favor
a different view of our behavioral evolution
...
The first posits a recent, rapid
change in behavior, presumably based on a genetic mutation
that enhanced cognitive function
...


The archeological background
In looking for signs of modern human behavior, we are concerned with a shift from the Middle Stone Age (MSA) to the
Later Stone Age (LSA) in Africa, dated at some 250,000 to

40,000 years and 40,000 to 10,000 years, respectively
...

The end of the Lower Paleolithic, 250,000 years ago,
saw the end of innovation-poor, long-lasting stone-tool
industries
...
The Middle Paleolithic (mode III) and Middle Stone
Age technologies were characterized by the predominance of
the prepared core technique, such as the Levallois technique
(see unit 25)
...
Some variation exists in Middle Paleolithic assemblages throughout
the Old World, which has encouraged the development of
a plethora of local names
...
(See figure 30
...
)
With the Upper Paleolithic, beginning 40,000 years ago,
the number of tools more than doubled again, to as many as
100
...
(See figure 30
...
) In addition to new forms of
tools, raw materials that were only infrequently used earlier,
such as bone, ivory, and antler, became very important in the
Upper Paleolithic industries
...
(See figures 30
...
5
...
The preparation of the cores used for their manufacture requires great skill and time
...
The blades,
often small and delicate, may be functional without further

30: Archeological Evidence

Figure 30
...
(top row, left to right) Mousterian point, Levallois
point, Levallois flake (tortoise), Levallois core, disc core
...
Scale bar is 5 cm
...
)

Chatelperronian
Aurignacian
Gravettian
Solutrean
Magdalenian Azilian
40,000 years
before present

30,000 years
before present

20,000 years
before present

209

Figure 30
...
(top row, left to right) Burin on a truncated blade,
dihedral burin, gravette point, backed knife, backed bladelet,
strangulated blade, blade core
...
Scale
bar is 5 cm
...
)

ence reveals “the most dramatic behavioral shift that archeologists will ever detect
...
If true, then it
would imply that the evolution of modern morphology
(which appeared more than 130,000 years ago) occurred
separately from the evolution of modern behavior (40,000
years ago)
...


10,000 years
before present

European evidence
Figure 30
...
In addition, the tool industries themselves
take on a complexity and refinement unmatched in earlier periods
...


preparation, or they may merely serve as the starting point
for specifically shaped implements
...
Thus, a strong sense of directed
design and elaborate use characterize Upper Paleolithic tool
assemblages
...

For Stanford University archeologist Richard Klein, the evid-

The European archeological evidence for the stages in question is extensive, and it does appear to give a clear signal of
a revolutionary change some 40,000 years ago
...
It coincides with the first appearance
of modern humans in the region, carrying the cultural tradition known as the Aurignacian
...
The sites are also
associated with other characteristics of the Upper Paleolithic:
they are larger than those of the Middle Paleolithic; open-air
(as opposed to rock shelter or cave) sites are more distinctive
and organized; artifacts indicate the existence of longdistance contact and even trade (shells and exotic stone that
must have come from afar); and musical instruments, specifically simple flutes made from bone, are present
...
4 Upper Paleolithic range
of forms: The French archeologist G
...
It forms the basis of all Upper
Paleolithic typologies
...


Figure 30
...
They were probably
used in rituals rather than in practical affairs
...

(Courtesy of Roger Lewin and Bruce Bradley
...
Although
sculpting and engraving appeared from the Aurignacian
onward, evidence of cave painting did not become strong
until the Gravettian, some 30,000 years ago
...
Although not every aspect of Upper Paleolithic
culture, especially technological advances and artistic traditions, was present from the beginning, overall it surely offers
evidence of a revolutionary change
...

The match between archeological and fossil evidence in
Europe is quite good
...
Virtually all hominin fossils associated with Upper Paleolithic assemblages have been modern
humans
...
Although the fossil evidence at Arcy-surCure is fragmentary, a classic Neanderthal partial skeleton
has been found at Saint-Césaire
...

Some scholars have argued that the intermediate nature of
the Chatelperronian technology indicates the presence of a
population in biological transitionathat is, changing from

30: Archeological Evidence
Neanderthal to modern humans
...
The age of the skeleton, recently dated at
36,000 years, leaves little or no time for an evolutionary
transition to local modern human populations
...
One possible explanation of the
Chatelperronian is that it was developed by late Neanderthal
populations that had cultural contact with incoming modern
human populations
...
It does not, however, address the
issue of the origin of modern humans
...
Great differences are also noted between western Asia
and eastern Asia, where the evidence is sparsest of all
...
Between 200,000 and 50,000 years
ago, this region was variously occupied by Neanderthal and
early modern humans, while the Far East was inhabited by
populations that were neither Neanderthal nor modern
...
If the transition
tracks the migration of modern humans out of Africa, through
the Middle East, and finally into western Europe, then the
evidence for it in the Middle East might be expected to predate the evidence gleaned further west
...
Evidence of Upper Paleolithic human remains in
the Middle East is scarce, but is essentially that of modern
humans
...
These fossil remains are either equal in age to or predate Neanderthals of the region, and thus would seem to preclude an evolutionary transformation of Neanderthals into
modern humans
...
It implies either that modern

211

human anatomy evolved long before modern behavior or
that the modernity of the Skhul and Qafzeh remains has
¯
been overstated
...

Klein points out that the Skhul/Qafzeh specimens are
¯
extremely variable anatomically and that they possess some
archaic features, such as prominent brow ridges and large
teeth
...
“However, it seems reasonable to
suppose that they were not yet fully modern biologicallya
perhaps, above all, neurologically
...

The interpretation of eastern Asian evidence poses a challenge because of the scarcity of sites and uncertain dating
...
One site in Sri Lanka,
Batadomba Iena cave, contains a microlithic tool assemblage
that has been radiocarbon dated at 28,500 years old
...
The migration
from Southeast Asia to Australia between 60,000 and 45,000
years ago implies the evolution of modern human behavior
by at least this date (see unit 34)
...


African evidence
For the past two decades, the Middle Stone Age of Africa
has been viewed as equivalent to the Middle Paleolithic in
Europe, both chronologically and technologically
...
This view is now being questioned
by some prehistorians, particularly by Alison Brooks and
Sally McBrearty, of George Washington University and the
University of Connecticut, respectively
...
Recently, McBrearty has reported blade production at
a site in central Kenya (the Kapthurin formation), which is
some 240,000 years old
...
6 Middle Stone Age bone
tools: Discovered recently in Zaire, these
harpoonlike bone points are the earliest
known examples of worked bone, dated
at between 90,000 and 160,000 years
old
...
)

than the oldest known blades from the European Middle
Paleolithic and more than 200,000 years older than those
from the European Upper Paleolithic
...

One explanation for this production could be that the
earlier blades were made by a less sophisticated technique
...
Instead, other behaviors must be considered as well,
such as production of tools made from materials other than
stone, artistic behavior, and other complex social behavior,
such as long-distance trade or exchange of objects
...
A striking
exception is a collection of barbed bone points (like harpoon
heads) found at the Katanda site in eastern Zaire, and
reported by Brooks and her colleagues in 1995
...
This discovery has encouraged
archeologists to reconsider claims for other bone tools at
several Middle Stone Age sites, though none is said to be as
old as those found at Katanda
...
The oldest, reliably dated rock painting
in Africa appears in the Apollo cave, Namibia, dated at
27,000 years, which is equivalent to the oldest examples of
art in Europe
...
If such pigments
were used for body decoration, for example, rather than
treating hide, it would be significant in the context of the current question
...
Evidence of personal adornment,
such as ostrich eggshell beads, appears in the record relatively late, about 60,000 years ago
...

Recent discoveries at the Blombos Cave, South Africa,
however, indicate that modern humans there were producing symbolic objects 77,000 years ago, or more than twice as
long ago as in Europe
...
The researchers
interpret these markings to be notations of the sort that are
seen in the European Upper Paleolithic
...
Again, these are typical of what is found in the European Upper Paleolithic
...
6
...
Once it passed a certain
threshold, that behavior appears to have exploded, producing the rich fabric of social complexity associated with the

Neolithic, etc
...


50

Last glaciation

3

Aurignacian and
modern H
...
sapiens

H
...


???
???
???

60

20
30
40

Middle Stone Age/
Mousterian and ?
early modern
H
...
sapiens

Last interglaciation

80

120

10

Modern H
...

Mesolithic

2

30
40

Eastern
Asia

"Late Paleolithic"

20

Western
Asia

Upper and "Epi-"
Paleolithic

10

Europe

Later Upper
Paleolithic

1

Holocene

Years ago
(x 1000)

O-isotope
stages and
climate
stratigraphy

213
Years ago
(x 1000)

30: Archeological Evidence

Howieson's Poort,
Aterian, and early
modern H
...
sapiens

120
130

6

Penultimate
glaciation

130

Middle Stone Age/
Mousterian and
early modern
H
...


Acheulean,
etc
...
7 Continents compared: The picture of modern
human origins derived from archeological evidence is at best
incomplete
...
In Asia, the

picture is less clear
...
(Courtesy of Richard Klein/Evolutionary
Anthropology
...
That explosion was a
cultural change, however, not a biological one
...
Undoubtedly this issue will continue to inspire debate for some time to come
...
7
...
Nevertheless, it can be argued that
a signal of modernity appears first in Africa, representing a
chronological precursor of what later appears in Eurasia
...
Thus, the “out of Africa” model is more strongly supported than the multiregional evolution model
...
Behavior and human evolution
...
,
eds
...
San Francisco:
California Academy of Sciences, Memoir 21, 1996
...
The case for continuity: observations on the
biocultural transition in Europe and western Asia
...
The human revolution
...

D’Errico F
...
Evol Anthropol 2003;12:188–202
...
Mode 3 technologies and the evolution of modern humans
...

Harrold FB
...
The
human revolution
...

Henshilwood CS, et al
...
Science
2002;295:1278–1280
...
The archeology of modern humans
...

———
...
J World
Prehistory 1995;9:167–198
...
Behavioral differences between archaic and
modern humans in the Levantine Mousterian
...

McBrearty S, Brooks SB
...
J Human Evol
2000;39:453–563
...
Major issues in the emergence of modern humans
...

Straus LB
...
Evol
Anthropol 1995;4:4–16
...
Lower Pleistocene hunting spears from Germany
...

Yellen JE, et al
...
Science 1995;268:553–556
...
Theories
explaining the evolutionary background to brain expansion centered
for a long time on practical factors, such as tool making and use, and
the needs of operating a hunter-gatherer way of life
...


The brain is a very expensive organ to maintain
...
Given the fact that the human
brain is three times larger than it would be if humans were
apes, we have to ask, Why and how did brain expansion
occur in the human lineage? And what were the selection
pressures that produced a cognitive capacity that surely far
outstripped the day to day practical demands of a huntergatherer way of life? (See figure 31
...
)
As we saw in unit 12, life-history factorsagestation length,
metabolic rate, precociality versus altriciality, and so ona
have an important impact on the size of brain that a species
can develop
...

The first, proposed by Robert Martin of the Field Museum,
Chicago, is that the mother’s metabolic rate is the key to the
size of brain a species can affordathe higher the metabolic
rate, the bigger the relative brain size
...
Although both hypotheses are said by
their authors to have empirical support, debate continues as
to which is the more germane
...

In being well endowed mentally, humans and other primates are a part of a very clear pattern among vertebrates as a

Figure 31
...


whole
...
Underlying this stepwise progression, which
takes into account successive major evolutionary innovations and radiations, is the building of more and more sophisticated “reality” in species’ heads
...
Two orders of mammal have
significantly larger brains than the rest of mammalian life:
primates and cetaceans (toothed whales)
...
Only humans are outliers from the monkey/ape axis:
the brain of Homo sapiens is three times bigger than that of an
ape of the same body size
...
For
instance, the adult ape brain is nearly 2
...
5 times
...
Even though
humans are of similar body size to apes (57 kilograms for
humans, compared with 30 to 100 kilograms for apes) and
have a similar gestation period (270 days versus 245 to 270
days), human neonates are approximately twice as large and
have brains twice as large as ape newborns
...

Another major difference is the pattern of growth
...
In humans, the prenatal phase of rapid brain growth continues for a longer
period after birth, a pattern that is seen in altricial species
...
This extension effectively gives humans the equivalent of a 21-month gestation
period (9 months in the uterus, and 12 months outside)
...
One important consequence is that human infants
are far more helpless, and for a much longer time, than the
young of the great apes
...


Fossil evidence
Two types of fossil evidence are related to brain evolution:
indications of absolute size, and information about the surface featuresaconvolutions and fissuresaof the brain
...

Brain size is the first and most obvious piece of information
to be gleaned, and it can often be gained even with partial
crania
...
This
interpretation is misleading, however, for two reasons: (1)
early australopithecines were smaller in body size than

1500
Homo
sapiens
1300

Average brain size (cm3)

218

1100

900

Homo
erectus
Homo
habilis

700

A
...
robustus
Orangutan

A
...
afarensis
300
0

20

40

60

80

100

120

Average body weight (kg)

Figure 31
...
Brain size did not change significantly
among the australopithecines or the modern apes, despite a large
body size difference in the latter
...
It
is therefore safe to say that brain expansion had already been
established by the time Australopithecus afarensis appeared
...
5 to 1
...
The size range for
Homo ergaster/erectus, dated at 1
...
The
comparable measurements for archaic Homo sapiens, including Neanderthals, range from 1100 to more than 1400 cubic
centimeters, or larger than in modern humans
...
Q
...
The australopithecine species have E
...
s in
the region of 2
...
1 for early Homo, 3
...
8 for modern humans
...
2 and 31
...
)
By looking at overall brain structure as revealed in endocasts, it is possible to differentiate between an apelike and a
humanlike brain organization
...
Very
briefly, a brain in which the parietal and temporal lobes predominate is considered humanlike, whereas apelike brains

31: Evolution of the Brain, Intelligence, and Consciousness

1500
Archaic sapiens

Avergae brain size (cm3)

1300
Modern
sapiens

Gradual trajectory

1100

H
...
habilis
Stepwise trajectory

500
A
...
3 Brains through time: A threefold increase in
absolute brain size occurred during the past 3 million years
...


Figure 31
...
The human brain is three times the size of
the ape brain
...
)

Frontal

Parietal

Temporal

Cerebellum

Lunate sulcus

Occipital

219

contain much smaller parietal and temporal lobes
...
(See figure 31
...
)
Anthropologists find it very helpful to know when a
human brain organization emerged in hominin history
...
His analysis included the position of the
lunate sulcus, a short groove that lies at the margin between
the occipital and temporal lobes
...
According to Holloway,
in all fossil hominin endocasts in which the lunate sulcus
could be discerned, this structure lies in the human position
...
The two researchers have since
exchanged more than a dozen papers, each defending
his/her position, but no resolution has been reached
...

If brain reorganization toward the human configuration
began only with the origin of Homo, while the australopithecine brain remained essentially apelike, then it would be
consistent with other events in human prehistory, including
the evolution of humanlike body proportions, the reduction
of body size dimorphism, and the first appearance of stonetool technology
...


Frontal

Broca’s area

Parietal

Temporal

Cerebellum

Occipital

220

Part Eight: The Human Milieu

Brains in modern humans are strongly lateralized, that is,
in the general population the left hemisphere is larger than
the right
...

This feature is assumed to be associated with tool making and
use
...


Measures of intelligence
It is relatively easy to plot brain expansion through hominin
history, but how are we to measure the rise of intelligence
through time? The archeological record is notoriously lacking in tangible indications of the working of the mind
...
As we saw in units 23,
25, and 30, the imposition of standardization and expansion
of complexity emerged very slowly in prehistoric stonetool industries
...
Apparently something
changed in the brains of the earliest hominin tool makers to
permit the development of this ability
...
Once
hominins shifted from the basic primate pattern of brain
growth, producing a much more helpless infant whose brain
continued to grow at the fetal rate, then greater allocation of
time and resources would be needed for rearing offspring
...


Possible causes of brain expansion
A long-popular notion was the hypothesis that the very obvious difference between hominins and apesathat humans
made and used stone toolsawas the most likely cause of
brain expansion: the tripling of hominin brain size was seen
as being accompanied by an ever-increasing complexity of
tool technology
...
” In either case, the emphasis was placed
on the mastering of practical affairs as the engine of hominin
brain expansion
...
” The new
insight begins with a paradox: Laboratory tests have demonstrated that monkeys and apes are extraordinarily intelligent,
and yet field studies have revealed that the daily lives of these
creatures are relatively undemanding, in the realm of subsistence at least
...
5 The social milieu: Socializing has become an
important part of primate life
...
Biologists now believe that the intellectual
demands of complex social interaction were an important force of
natural selection in the expansion of primateaand ultimately,
humanabrains
...
5)
...
In other words,
for a nonhuman primate in the wild, learning the distribution and probable time of ripening of food sources in
the environment is intellectual child’s play compared with
predictingaand manipulatingathe behavior of other individuals in the group
...
Not so in monkeys
and apes
...

As a result, a physically inferior individual can triumph over
a stronger individual, provided the challenge is timed so that
friends are at hand to help the challenger and that the
victim’s allies are absent
...
6 Social complexity and
increased intelligence: The need to cope
with rising social complexityaincluding
increasingly demanding subsistence
patterns but particularly a more ramified
social structure and unpredictable social
interactionsamay have represented a key
selection pressure for increased intelligence
...

Cheney and her colleagues had no difficulty in finding
many examples of primate behavior that appear to reflect
humanlike social cognition
...
” Supporting this hypothesis, known as the
Machiavellian intelligence hypothesis, the British anthropologist Robin Dunbar has found that primate species with more
complex social interaction have larger cerebral cortexes
...
Why have primates found it advantageous to
indulge in alliance building and manipulation? The answer,
again gleaned from field studies, is that individuals that are
adept at building and maintaining alliances are also reproductively more successful: making alliances opens up potential mating opportunities
...
“Once a society has reached a
certain level of complexity, then new internal pressures must
arise which act to increase its complexity still further,” he
explains
...
And in these circumstances there can be no going back
...
Consciousness is a toolathe ultimate toolaof the social animal
...
Consciousness builds a better realityaone that
is attuned to the highly social world that humans inhabit
...
6
...
The expensive-tissue hypothesis
...

Byrne R
...
Oxford: Oxford University Press, 1995
...
The emergence of intelligence
...

Dunbar RIM
...
J Human Evol 1992;22:469–493
...
The social brain hypothesis
...

Falk D
...
5 million years of hominid brain evolution
...

Humphrey NK
...
Oxford: Oxford University Press, 2002
...
The prehistory of the mind
...

Noble W, Davidson I
...

Cambridge, UK: Cambridge University Press, 1996
...
How mammals produce large-brained offspring
...

Seyfarth RM, Cheney DL
...
Sci Am
Dec 1992:122–128
...
Pan the tool-maker: investigations into the stone toolmaking and tool-using capabilities of a bonobo (Pan paniscus)
...

Wills C
...
New York: Basic Books, 1993
...
The Tarzan syndrome
...

Wynn T
...
In: Foley
RA, ed
...
London: Unwin Hyman,
1991:52–66
...
Questions of
when and why spoken language evolved are central to understanding
our species
...
Why language evolved is equally perplexing
...


One great frustration for anthropologists is that, by its nature,
language is virtually invisible in the archeological record
...

One general question about the evolution of human
language relates to the dynamics of its emergence
...


Fossil evidence
In recent years, researchers have pursued several kinds of
evidence from fossil hominins
...
Second, indications of the structure of the voiceproducing apparatus in the neck (the larynx and pharynx)
provide clues as to language ability, as do also the size of the
hole in the cranium through which the nerve to the tongue
passes, and the degree of innervation to the diaphragm, as
reflected in the size of the spinal canal
...
As with many

complex mental functions, however, language capabilities
cannot be pinpointed precisely to particular centers
...
A second
center, Wernicke’s area, located somewhat behind Broca’s
area, is involved in the perception of sound
...
1
...
Many aspects of language
afor instance, the lexicon, or vocabulary with which we
workadefy precise localization
...
Signs of
Broca’s area have been found in Homo rudolfensis and later
species of Homo, but not in australopithecines
...
She disagrees with Ralph Holloway, however,
who argues that language capacity began to develop earlier,
among australopithecine species
...
In contrast, Falk sees no reorganization in the
human direction until Homo evolves (see unit 31)
...
The human vocal
tract is unique in the animal world
...
2)
...
The second pattern places the larynx low in the
neck, requiring temporary closing of the air passage during
swallowing; otherwise solids or liquids will block it and cause
choking
...
The
low position of the larynx greatly enlarges the space above it,
which allows the sounds emitted from it to be modified to a

32: The Evolution of Language
Broca’s area

Figure 32
...

These language centers are usually located
in the left cerebral hemisphere, even in
many left-handers
...
Nonhuman mammals are limited to modifying
laryngeal sounds by altering the shape of the oral cavity and
the lips
...
5 to 2 years; the larynx then begins to
migrate lower in the neck, achieving the adult configuration
at approximately age 14 years
...
In adult humans, this structure is arched;
in other mammals, and in human infants, it is much flatter
...
What does the fossil record
indicate?
“In sum,” says Laitman, “we find that the australopithecines probably had vocal tracts much like those of living
monkeys or apes
...
”
Unfortunately, the fossil record for Homo rudolfensis/habilis is
poor as far as indications of the basicranium are concerned
...
may
have begun to descend into the neck, increasing the area
available to modify laryngeal sounds
...
Only with the origin of archaic Homo sapiens,
some 300,000 years ago, does the fully modern pattern
appear, indicating at least the mechanical potential for the
full range of sounds produced by people today
...
In modern humans the hypoglossal nerve is much
larger than in other nonhuman primates
...
They found that
by 400,000 years ago, the nerve was apparently already
enlarged to modern standards
...
This is, however, controversial
...
This is, she
says, related to the need for fine control of breathing, via the
diaphragm, which is required for speech
...
6 million years ago
...


The question of Neanderthals
A continuing controversy concerns Neanderthals’ language
abilities
...
However, basicranial flexion is less than that observed in earlier archaic
sapiens
...


224

Part Eight: The Human Milieu

N

N

H
S
T

P
E

H

S
T

P
E
L

L
V
V

Figure 32
...
In the chimpanzeeaas in all mammalsathe larynx is high in
the neck, enabling simultaneous breathing and swallowing
...
Below is a
sketch of the australopithecine vocal tract, which resembles that of
the chimpanzee
...
Laitman, Patrick Gannon, and
Hugh Thomas
...

The notion that Neanderthals had poorly developed language abilities, and that this may have contributed to the
extinction of the species, has become the majority position
among anthropologists
...
In 1989, a team of researchers led by Baruch
Arensburg, of Tel Aviv University, reported the discovery of
a hyoid bone from a Neanderthal partial skeleton, at Kebara
...
In size and shape, the Kebara hyoid
is virtually identical to the modern bone
...
Laitman
challenges this conclusion, saying that the anatomy of the
hyoid bone is insufficient evidence for inferring the overall
shape of the vocal tract
...

A second challenge to the accepted view comes from David
Frayer, of the University of Kansas
...
Frayer also argues that
basicranial flexion in other Neanderthals falls within the
range of other Upper Paleolithic and Mesolithic European
populations
...
In any case, he
says, measurements from the new reconstruction still imply
a relatively undeveloped vocal tract for Neanderthals
...

As mentioned in unit 27, the hypoglossal canal in
Neanderthals is similar in dimensions to that in modern
humans, which may reflect a capacity for articulate speech
(see above)
...

Overall, fossil endocasts and laryngeal structure indicate a
rather gradual acquisition of language capabilities through
hominin history, possibly beginning with the origin of the
genus Homo
...
Evidence from spinal cord and hypoglossal
canal measurements indicate a rather later emergence, some
400,000 years ago
...
For instance, when juvenile monkeys are threatened
by an older opponent, they scream, which usually brings
help
...
Experiments with tape-recorded screams show
that mothers’ responses to the screams vary according to the
indicated danger
...
Although the different calls are not “words,” they do
appear to be labels
...
Terrence Deacon, of Harvard University, suggests that neurological evidence supports such a
scenario, and that language origins began with the genus
Homo and developed gradually
...
In other words, these
researchers argue that human language is not part of a continuum with primate vocalization
...
If true,
then following the trajectory of the complexity of stone-tool
technology through time should reveal something about the
change in language capabilities
...
“It is true,” he says, “that language and tool making are
sequential behaviors, but the relationship is more likely to be
one of analogy rather than homology
...
Thus, one cannot look
at the complexity of a tool assemblage on one hand and learn
anything directly about language abilities on the other
...
He has argued that the complexity of a tool assemblage might provide some information about social complexity, not cognitive complexity, relating to mechanical or
verbal processes
...

Discerning such a relationship is to some extent an abstract
exercise, which would be impossible in the complete absence
of language
...
3
...
3 Sharpening the mind,
sharpening the tongue: With the passage
of time and the emergence of new species
along the Homo lineage, stone-tool making
became even more systematic and orderly
...

The increased orderliness in stone-tool
manufacture must, argued archeologist
Glynn Isaac, reflect an increasingly ordered
set of cognitive processes that eventually
involved spoken language
...
(II)
Acheulean (Olorgesailie): 2a = scrapers;
2b = nosed scrapers; 2c = large scrapers;
3 = handaxes; 4 = cleavers; 5 = picks; 6 =
discoids
...
(IV) Upper
Paleolithic: 2a = grattoir; 2b = nosed scraper;
2c = raclette; 3 = percoir; 4 = point; 5 =
burins; 6 = backed blades
...
)

225

some 2
...

What lessons do we learn from this basic archeological evidence, in relation to origins of language? Writ on the large
scale, it seems reasonable to infer that a language complex
enough to conjure the abstract elements of social rules,
myths, and ritual is a rather late development in hominin
history; that is, it began only with archaic Homo sapiens, and
became fully expressed only with anatomically modern
humans
...
Only in the later stages of hominin history does this
organization take on a degree of sophistication that would
seem to demand language skills
...

Painting or engraving an image of, for example, a bison
does not necessarily imply anything mystical about the
motives in the artist’s mind
...

But the art created in the Ice Age was not simply a series of
2a
4
2d

IV
2b

3

III
2c

2b
II

2a

5
4

2c 65

n

lea

heu

Ac
I

1
2

n

wa
do

Ol

pe

6

2d

n

ria

ste

u
Mo

al
rP

ic

ith

eol

Up

3
3

1

5

2b

4

2c
6

2a

226 Part Eight: The Human Milieu
simple abstractions of images to be seen in the real world (see
unit 33); rather, it was a highly selective abstraction
...
It was, in fact, a world
like ours, just technologically more primitive
...
Although claims of
some form of abstract artistic expression date back to 300,000
years ago, it is not until a little more than 30,000 years ago
that artistic expression really began to blossom (see unit 33)
...
Two pendantsaone from reindeer bone,
the other from a fox toothawere discovered at the 35,000year-old Neanderthal site of La Quina, France; an antelope
shoulder blade etched with geometric pattern was also found
at another French site, La Ferrassie
...
The engraved pieces of ochre found in the
Blombos Cave, South Africa, date a little earlier, to almost
80,000 years
...
The late British anthropologist
Kenneth Oakley was one of the first to suggest, in 1951, that
this “something important” was best explained by a quantum
jump in the evolution of language
...

Thus, the line of evidence from artistic expression suggests
that the dynamic of language evolution was rapid and recent
...
It
concerns a gene that is linked to the ability to produce articulate speech
...
Richard Klein, of
Stanford University, has long argued that language appeared
as a result of a relatively recent mutation affecting brain
wiring in relation to speech, perhaps 50,000 years ago
...


ment was pursued by a variety of anthropologists
...
A popular hypothesis of language evolution
included the notion that a first stage would have been a gesture languageagesturing, remember, is something humans
do frequently, especially when lost for words
...
From the practical world of communication,
explanation of language origins now turns to the inner mental world and social context
...
“We can think of language as being an
expression of another neural contribution to the construction of mental imagery
...
” As we saw in unit 31, anthropologists are beginning to recognize the importance of social
interaction as the engine of the evolution of hominin intelligence
...

More recently, Robin Dunbar has suggested that language
may have evolved as a way of facilitating social interaction in
human groups, the equivalent of grooming in nonhuman
primates
...
Language is

Abstraction

Communication

Function

Function
Spoken language

Origin

Function

Imagery to create a
better reality

What caused the evolution of
language?
The most obvious cause for the evolution of language was its
development within the context in which it is so obviously
proficient: communication
...
4 Origin and function of language: Although
communication is clearly an important function of spoken language,
its origins (and continued functions) probably centered on creating
a better image of our ancestors’ social and material worlds
...
These lines of investigationathe inner mental world
and the social worldasupport an early, gradual dynamic of
language evolution
...
4
...
5)
...
Archeological (and genetic) evidence, ranging
from stone-tool manufacture to artistic expression, is read to
imply a recent, rapid evolution
...

Most of the expansion of hominin brain size occurred
before material and abstract expressions of culture became
really vibrant
...
Many examples in
biology, however, include dramatic emergent effects as
thresholds are passed
...


?

Neanderthal

?
?
2
1
Millions of years ago

Upper
Paleolithic

(c)

3

Present

Brain size
Brain organization
Presence of Broca’s area

Australo- Homo
pithecine shabilis

Figure 32
...

Archeological evidence indicates a recent,
rapid evolution, whereas evidence about
the brain and vocal tract implies an early,
gradual evolution
...
)

Neurobiological
measures

Acheulean

Archaic
sapiens
(including
Neanderthal)

“Humanness”
of basicranium

Oldowan

Upper
Paleolithic

Mousterian

(Humanlike)

Upper
Paleolithic

Archeological signal
of complexity

(a)

227

0%
Present

Measured points
Estimated points

KEY QUESTIONS
• What is the relative importance of the different lines of fossil evidence in revealing past language capabilities?
• How would one test the idea that conformity of stone-tool production implies the imposition of social rules, and therefore the
existence of language?
• What type of artistic expression provides the most persuasive
evidence of the existence of language?
• If human language is discontinuous with primate vocalizations and
communications, how might it have arisen?

KEY REFERENCES
Cartmill M
...
Discover Dec 1998:56–64
...
The language hypothesis for the Middle-to-Upper
Paleolithic transition
...

Davidson I
...
In:
Christiansen MH, Kirby S, eds
...
Oxford:
Oxford University Press, 2003:140–157
...
The archeology of depiction and language
...

Deacon TW
...
New York: WW Norton, 1997
...
Grooming, gossip, and the evolution of language
...

Enard W, et al
...
Nature 2002;418:869–872
...
Language origins: the silence of the past
...

Gannon P, et al
...

Science 1998;279:220–222
...
Tools, language, and intelligence
...

Jerison HJ
...
59th James Arthur
Lecture, American Museum of Natural History, 1991
...
The anatomy of human speech
...


Lieberman P
...
Behav
Brain Sci 1996;19:156–157
...
Eve spoke: human language and human evolution
...

Noble W, Davidson I
...

Cambridge, UK: Cambridge University Press, 1996
...
Computational and evolutionary aspects of language
...

Pinker S, Bloom P
...
Behav
Brain Sci 1990;13:707–784
...
Visualizing the mind
...


ART IN
PREHISTORY

33

Traditionally, the study of prehistoric art meant the study of
prehistoric art in Europe, specifically in southwest France
and northern Spain, created during the period 35,000 to
10,000 years ago (the Upper Paleolithic), the end of the
Pleistocene Ice Age
...
1
...
The painted caves and engraved objects at, principally,
European sites display a range of animal species crafted with great
skill
...
Rather, they
are of individual animals, occasionally showing some minimal interaction
...
Many theories have been put forward to explain the “meaning”
of the art, but it still remains elusive
...
1 Distribution of art sites
in Europe: The limestone caves of Ice Age
Europe have preserved a rich legacy of
Paleolithic art
...


ROME

Cave with wall art
Engravings and art mobilier

230 Part Eight: The Human Milieu
might give some insight into the workings of the human
mind at this point in our history
...

The most spectacular new finds, however, have occurred in
France, with the discovery of Chauvet Cave in the Ardèche,
southern France, and Cosquer Cave, on the southern coast
near to Marseilles, and in Portugal, at the Côa Valley
...
For
instance, carved and engraved images were thought to have
preceded painted images by at least 10,000 years
...
Moreover, the painted wall
art consists mainly of large mammals, such as bison, aurochs,
deer, horses, mammoth, ibex, and so on; carnivores are rare
and usually sequestered in the deepest recesses of caves
...
At Chauvet, however,
carnivores are prominent among the painted images, and
they include a hyena and a leopard, animals not previously
seen in prehistoric art
...
The painted
images are often very good, naturalistic representations of
single animals or small groups of individuals, but they convey little sense of natural scenes
...
Hand stencilsaproduced by brushing or blowing pigment around the hand while placed on a rock surfacea
are relatively common, often revealing what appears to be
missing fingers
...

Painted images are usually scattered on rock surfaces in a
seemingly random manner, often with one image superimposed partially or wholly on another
...

Engraved or carved images, particularly on portable objects
such as spear throwers, batons, pendants, and blade punches,
often contain more detail in their execution
...
For instance, birds, fish, and plants are often
depicted, sometimes in rich combination; again, this illustration seems not to be the representation of a scene so much
as an idea, such as a season
...
(See figure 33
...
)
The human image occurs more frequently in carved
and engraved images than in painting
...
” However, one site, La Marchè in the French
Pyrenees, contained a cache of more than 200 small engraved
human faces, completely lifelike and individualisticaa portrait gallery from 20,000 years ago
...

Geometric patterns became predominant, and people apparently no longer sought out deep caves in which to paint
...


Interpretations of prehistoric art
The first systematic study of Ice Age art was undertaken by
the great French archeologist, the Abbé Henri Breuil
...
He, and later scholars,

Figure 33
...
Apparently used as an implement for shaping flint
tools, the antler fragment is engraved with a pregnant mare, which
seems to have been symbolically killed by a series of engraved
arrows
...
(b) A drawing of the surface of the antler, “unrolled
...
Perhaps used in straightening the
shafts of arrows or even spears, the baton’s collection of engraved
items suggests a representation of spring
...
” (e) Vogelherd horse, carved from mammoth ivory
some 30,000 years ago and worn smooth by frequent handling
over a long period of time
...
(f) The black outline of
this horse was painted on the wall of a cave, Peche-Merle, France,
approximately 15,000 years ago
...
The
black hand stencils are also later additions
...
)

33: Art in Prehistory

(a)

(b)

(e )

(d)

(f )

(c)

231

Climate changes
Cool
Temperate

232 Part Eight: The Human Milieu

Magdalenian
Solutrean
Gravettian
Chatelperronian
Aurignacian

38

36

34

32

30

28

26

24

22

20

18

Time (thousands of years ago)

believed that the art would grow more sophisticated through
timeahence the notion that the famous Lascaux Cave (dated
at 17,000 years old) was the high point of prehistoric art,
given its brilliance in color and incorporation of perspective
...

Breuil developed the hypothesis that prehistoric art was
also “hunting magic”athat is, a way of ensuring fruitful
hunts and propitiating the victims
...
Even the absence of such
weapons does not militate against the idea, because an
animal’s image might be impaled symbolically during a ritual
performance in front of it
...
In many
cases, these bones show that reindeer were important as food
ayet reindeer images are few
...
As the French philosopher Claude Lévi-Strauss
once observed, certain animals are depicted frequently, not
because they were “good to eat” but because they were “good
to think
...
This
thesis was developed independently by French archeologists André Leroi-Gourhan and Annette Laming-Emperaire
...

For Leroi-Gourhan and Laming-Emperaire, wall art
reflected the duality of maleness and femaleness in society
...
The cave images were arranged so that female
representations occurred at the center, with male representation located around the periphery, thereby reflecting a

16

14

12

10

Figure 33
...
The
changes took place against temperature
fluctuations of the late Ice Age
...
(Courtesy of the Randall
White/American Museum of Natural
History
...
Although the two researchers
did not fully agree on which images represented maleness
and which femaleness, their work had the important effect of
emphasizing social context in interpreting Paleolithic art
...
Both explanations,
however, were essentially monolithic
...
“We are beginning to see a great
deal more diversity and complexity in Upper Paleolithic art,”
explains Randall White of New York University
...
”
The Upper Paleolithic is divided into different cultural
periods, based upon the tool technologies of the time (see
unit 30 and figure 33
...
Throughout these different cultures, different aspects of the art changed in various ways,
as Breuil noted in his chronology
...
“In addition to differences through time,
there are differences between regions, real geographic variations
...
Thus, a monolithic explanation of the meaning of the art
is impossible
...

Ritual of other kinds almost certainly centered on the art
as well
...
South African archeologists
David Lewis-Williams and Thomas Dowson have suggested
that the art is shamanisticathat is, produced by shamans in
or after a state of trance
...
4
...

During trance-induced hallucination, the subject experiences a small set of so-called entoptic (“within the nervous

33: Art in Prehistory

Figure 33
...

A small antelope, bleeding from the nose, and therefore dying,
stands on a double line of white dots
...
This image is from the site of Maclear, in
the eastern Cape, South Africa
...
)

system”) images, such as grids, zigzags, dots, spirals, and
curves
...
Images that reflect these trance experiences
are common in shamanistic art, in South Africa and elsewhere; Lewis-Williams suggests that they may have been
part of Upper Paleolithic art, too
...

Remember that Breuil had suggested that chronology could
be inferred from style, given that style was held to change
and improve over time
...

The images were stylistically similar; thus, under Breuil’s
scheme, they should have been the same age
...
A third image, from
the Niaux Cave in the French Pyrenees, differed stylistically
from the Spanish images; under Breuil’s scheme, it would
be expected to have been made at a different time from those
in the Spanish caves
...
Clearly, age and style do not
always coincide
...
Some carry pictures of animals, fish, and plants;
others include series of seemingly random notches
...
He
suggested that some of the image combinations might
represent seasons of the year: the images of a male and a
female seal, a male salmon, two coiled snakes, and a flower

233

in bloom, all engraved on a reindeer antler baton, is one such
example
...
The discovery of Chauvet reinforces this point
...

Diversity, then, begins to emerge as a more realistic interpretative lens through which to view the Upper Paleolithic
aa diversity of people, a diversity of cultures, and a diversity
of the art
...
Most of all, an attempt
is being made to divest modern interpretations of the bias
inherent in modern eyes and minds
...
” (See figure 33
...
)

Precursors to Upper Paleolithic art
A persistent question in archeology relates to the dynamic of
the origin of symbolic image making: Were hominins less
advanced than Homo sapiens capable of symbolic expression?
Archeologists remain divided over the evidence and over its
interpretation
...
)
A decade ago, two anthropologists at the University of
Pennsylvania, Philip Chase and Harold Dibble, surveyed the
evidence for artistic and symbolic expression in the Middle
to Upper Paleolithic transition, with the expressed purpose
of determining the mode of the transition
...
” John Lindly and
Geoffrey Clark, of Arizona State University, strongly disagree
...
According to the two researchers, the
complexity of artistic expression in the Upper Paleolithic
increases with time, with the Magdalenian being more developed than the Aurignacian
...
“I have been struggling
to understand the rich body of Aurignacian and Gravettian

234

Part Eight: The Human Milieu
Implications for
structure

Main hypothesis

Associated with

1980s
Some structure

Social context

1960
Highly structured

Social allegory

Several scholars

André LeroiGourhan
Annette LamingEmperaire

1940s
Some structure

Hunting magic

Abbé Henri Breuil

1900s
No structure

Art for art’s sake

evidence, especially body ornamentation, from Western,
Central, and Eastern Europe,” he says
...
” Others, including Paul Mellars, of
Cambridge University, support White’s view that the origin
of symbolic art was punctuational
...
Oldest of all is an ox rib engraved with a series of double
arcs, from the French site of Peche de l’Azé, dated as being
some 300,000 years old
...
Nevertheless, argue Chase and Dibble, none of
this art betrays modern human symbolism at work, merely
weak glimmerings of its eventual development
...
5 Changing theories: After
cave and portable art was finally accepted
(in the late 1890s) as a genuine product of
ancient people, scholars’ interpretations
of its meaning evolved through different
stages
...
The
different hypotheses offered different
explanations of how the art was
distributedastructuredawithin the caves
...

More recently, Robert Bednarik, of the Australian Rock
Art Association, has been promulgating the cause of preUpper Paleolithic art, arguing that it has not been recognized
because archeologists believed it to be nonexistent (but see
unit 34)
...
Dated at 400,000 years, it would
be the oldest known figurine
...

Marshack has been applying microscopic analysis to incised
flint pieces from the 54,000-year-old site of Quenitra, Israel,
and a shaped piece of volcanic tuff from the Acheulean site of
Berekhat Ram, which is between 233,000 and 800,000 years
old
...
Although his findings
may well be correct, many archeologists remain resistant to
the notion that nonutilitarian artifacts prior to the Upper
Paleolithic in Europe signify substantial symbolic, or abstract,
expression
...
New developments in Pleistocene art
...

Bednarik RG
...

Curr Anthropol 1995;36:605– 616
...
400,000 year old figure from Morocco
...

Chase PG, Dibble HL
...
J Anthropol Archeol 1987;6:263–296
...
Rhinos and lions and bears
...

Conkey M, Soffer O, eds
...

San Francisco: California Academy of Sciences, 1997
...
The power of pictures
...

Beyond art: Pleistocene image and symbol
...

Davidson I, Noble W
...
Curr
Anthropol 1989;30:125–156
...
Technology, motion, and the meaning of epipaleolithic
art
...

D’Errico F, Villa P
...
J Human Evol
1997;33:1–31
...
Cognitive and optical illusions in San rock art
research
...

Lewis-Williams JD, Clottes J
...
Anthropol
Consciousness 1998;9:13–21
...
Symbolism and modern human origins
...

Marshack A
...
Curr Anthropol
1996;37:357–365
...
The Venus figurines
...

Valladas H, et al
...
Nature 1992;357:68–70
...
Visual thinking in the Ice Age
...

Extensive information, including virtual visits to major sites, can be
found on: http://witcombe
...
edu/ARTHprehistoric
...


PART 9

NEW WORLDS
34 The Americas and Australia
35 The Origin of Agriculture and the
First Villagers

34

THE AMERICAS
AND
AUSTRALIA

The Americas were long thought to have been first colonized shortly
prior to 11,500 years ago, based on archeological evidence
...
Linguistic and genetic evidence
points to even earlier dates, perhaps as much as 30,000 years ago
...
Their entry coincided with the disappearance
of megafauna
...
Although paleontological, archeological, linguistic,
and genetic evidence has been sifted to clarify the issue, the
dates and modes at which these dispersals occurred remain
uncertain
...
Of course, in some respects the path
of human history has been determined solely by the rather
special behavioral repertoire displayed by the genus Homo
...

For example, as Alan Turner of Liverpool University has
argued, the initial dispersal from Africa and the later
migration to North America can be viewed as territorial
expansions in concert with other large predators
...
One
can only speculate, however, about the precise motivations of the first Australian colonists when they struck out
in small boats for a land unseen
...


The Americas
Although population source (Asia) and the route (across the
Bering Strait that separates Alaska and Siberia) are undisputed, no consensus has been reached over the timing of this
migration
...
By 11,500 years ago, the Americas had
clearly been peopled, as evidenced by the extensive archeological remains of Clovis and then Folsom cultures, evidence
of which was first unearthed in the 1930s
...
Until recently there was wide agreement
that Native Americans were descended from at least two
migrations
...

Whenever they arrived, the first Americans found a land
very different from the one we know today
...
Throughout this time, at least part of
North America was mantled with ice
...
The Cordilleran ice sheet ran ribbonlike up
the Pacific coast from Washington State toward Alaska, submerging all but the highest peaks of the Rockies and the
mountains of western Canada
...

These individuals could have made the intercontinental
crossing dry-shod or by island hopping, because the Beringia
land bridge, which linked Siberia with Alaska, was fully or

240 Part Nine: New Worlds

Beringia

Timor Straits

Land masses 18,000 years before present
Ice sheets 18,000 years before present

partly exposed for much of that time as the result of a drop
in sea level; this fall in sea level measured as much as 100
meters at the glacial maxima, with the water being locked up
in the greatly expanded polar ice caps
...
(See figures 34
...
2
...
Most of
these claims have been viewed skeptically, with only a few
being accepted as valid
...
The explosion of
sites from 11,500 years ago onward presumably reflects an
explosion of populations, either from people already present
in the continents or from a new migration
...
3
and 34
...
)
Recently, some of the more famous “old” sites have lost
their claims at predating Clovis
...
Del Mar Man, a collection of skulls once
dated at 70,000 years, have been redated at approximately
8000 years
...
Nevertheless,
Richard Morlan, of the University of Toronto, believes that
another Yukon site, Bluefish Caves, may prove to be in the

Figure 34
...
Expanded glacial cover (white areas)
lowered sea levels to expose the shallow
continental shelf (shaded areas over current
coastlines)
...
The reduced
glaciation some 20,000–30,000 years ago
might also have left an ice-free corridor
linking North America and Siberia
...
This last site relates to people
north of the ice sheets, however
...

The evidence for Monte Verde’s early date has recently
become particularly strong, and most skeptics became convinced of its authenticity during a site visit in late 1996
...
Many archeologists remain skeptical that the
stone artifacts on which the claim is based are truly manmade; they may actually represent the result of natural stone
breakage
...
Skeptics point out the possibility that the site’s
material has suffered contamination with carbon from
nearby coal deposits, which would corrupt the radiocarbon
dating used at the site
...
2 In the grip of the ice: At
the peak of the last glaciation, some 18,000
years ago, much of North America was
covered by thick ice sheets
...
There is still dispute as to whether
an ice-free corridor existed throughout
the period or was temporarily closed
...
Porter
...
This dating issue remains to be
resolved
...

Archeologists now agree that a pre-Clovis people existed in
the Americas, perhaps as early as 30,000 years ago
...
As
David Meltzer, of Southern Methodist University, recently
observed, “Clovis, in that situation, may reflect the visible
portion of a population curve that began much earlier
...
5
...
Stanford University linguist Joseph
Greenberg has analyzed the 600 languages that survive, tracing them back to just three source languages: Amerind, the
most widespread and diversified; Na-Dene, less widespread
and diversified than Amerind; and Aleut-Eskimo, an even
less widespread and diversified language than Na-Dene
...

Several molecular biology laboratories are conducting
mitochondrial and other DNA analysis, so far without reaching an agreement as to whether the present population
descends from a small founder population or from a large
population
...
The amount of genetic diversity among the lineages
has been estimated variously to indicate separation as long as
78,000 years ago
...
That later
date has yet to be determined, although several estimates
close to 30,000 years ago have been made
...
Meanwhile,
similar work at Oxford University and at the University
of Michigan has led to the conclusion of a single migration;
in Japan, researchers have inferred four migrations from
mitochondrial DNA data
...


Figure 34
...
The Clovis point,
which usually measured about 7 centimeters in length, was
apparently inserted into the split end of a spear shaft and bound in
place by hide
...


Human impacts of the entry into
the Americas
Figure 34
...
As this diagram shows, dating
of the sites lies in a tight range between 11,500 and just less than
11,000 years ago
...


10,000

11,000

12,000

Bonfire

Hanson

Folsom

Clovis

Agate Basin

Hell Gap

Lindenmeier

Murray Springs

Lehner

Domebo

Folsom sites

Lange/Ferguson

Clovis

Dent

Colby

U
...
Mammoth

Mill iron

Agate Basin pre-Folsom

Clovis sites

Dry Creek

Owl Ridge

Moose Creek

Walker Road

radiocarbon years ago

Time scale in

Alaska

The Americas of the Ice Age differed dramatically from
today’s world
...
Huge freshwater lakes

34: The Americas and Australia

243

Taima-Taima
Greenland
ice sheet

Beringia

Nenana
complex

Bluefish
Caves

Toca do Boqueirao
da Pedra Furada

Cordilleran
ice sheet

Toca da Esperanca

Laurentide
ice sheet

Ice-free
corridor

Tagua-Tagua
Folsom
Pendejo
Cave

Meadowcroft
cave shelter

Clovis

Monte Verde
Windover

Los Toldos

Figure 34
...

Pedra Furada, in Brazil, is the least likely candidate of those shown
...
The great equatorial forests of
Central and South America survived in sheltered “refuges,”
having largely been replaced by open grassland and
woodland
...

They were replaced by Folsom people, who produced
smaller, more finely crafted projectile points
...
Clovis
people hunted mammoth and mastodon
...
Gone, too, were the great majority of large
mammals, with some 75 species eventually going extinct and
a few becoming restricted to South America
...
Some authoritiesa
Paul Martin of the University of Arizona being the most
prominentaargue that the animals had been wiped out by a
wave of Clovis and then Folsom hunters, advancing north
to south for a millennium
...

(See figure 34
...
)
Invasion of new lands by humans has been known to
cause significant extinctions in relatively recent history
...
Thus, while both explanations are plausible, neither has been demonstrated beyond
reasonable doubt in this case, although the overkill hypothesis has weakened of late
...
Even with sea levels at their lowest during
glacial maxima, the journey from Sunda Land (the combined
landmass of Southeast Asia and much of Indonesia) to the
Sahul landmass (Australia, Tasmania, and New Guinea)
would have required eight sea voyages, the last covering 52
miles
...
Coastal sites during the Ice Age are mostly now
submerged beneath the sea, however
...

Although hominins have been present in Southeast Asia
for almost 2 million years, the first evidence of occupation in
the Sahul outside of Australia is just 40,000 years old, taking
the form of an archeological site on the northeast coast of
New Guinea
...
(See figure 34
...
)
Until recently, the earliest known archeological sitesa
Malakunanja and Nauwalabila, in Arnhem Land, northern
Australiaawere approximately 50,000 years old
...
Even more contention sur-

8500

7500

Figure 34
...
S
...
The arrow and
shaded column above it indicate the
approximate time of activity of Clovis
hunters in the region
...


rounded claims for the archeological site of Jinmium, also
in northern Australia; in late 1996, it was reported to be at
least 60,000 years old and perhaps as much as 176,000 years
...

The oldest human fossils, which have recently been dated
to 42,000 years, come from Lake Mungo, in southern
Australia
...
Artifacts near the fossil sites have also been recently
dated, to 50,000 to 46,000 years
...
Details of the cranium have yet to
be published
...
7 Australian evidence:
Major archeological and fossil sites (with
dates, in thousand years BP, where known)
are shown here
...


Mungo (40–50)
Cohuna (14)
Kow (14)
Swamp

Devils Lair

0

with thin cranial bone, well-rounded foreheads, weak brow
ridges, and small mandibles
...
These specimens are more
robust than the Lake Mungo people, having thick cranial
bone, large and projecting faces, prominent brow ridges, and
large mandibles
...
These researchers suggest that the gracile people
came from China, while the robust colonists migrated from
Indonesia
...
In fact, the division
of the earliest fossils into gracile and robust is somewhat
artificial, argues Phillip Habgood, of the University of
Sydney
...
” This
concept is known as the homogeneity hypothesis
...
The source
population (or populations) for the earliest Australians
remains unresolved (see unit 28)
...

Extinctions did occur that were apparently clustered around
50,000 years ago, which coincides with the date for the archeological site at Lake Mungo
...


246 Part Nine: New Worlds

KEY QUESTIONS
• Why has it proven so difficult to establish a pre-Clovis presence in
the Americas?
• What factors might lead to the conflicting conclusions that are
being reached with genetic evidence on the peopling of the
Americas?
• What population factors might lead to a highly variable population
among the early Australians?
• What is the likelihood of an entry date into Australia that exceeds
100,000 years ago?

KEY REFERENCES
Adcock GJ, et al
...
Proc Natl Acad
Sci USA 2001;98:537–542
...
New ages for human occupation and climatic
change at Lake Mungo, Australia
...

Brown P
...
Phil
Trans Roy Soc B 1992;337:235–242
...
The Late Pleistocene cultures of South America
...

Dillehay T, Meltzer DJ, eds
...

New York: CRC Press, 1991
...
Mitochondrial DNA studies of Native Americans:
conceptions and misconceptions of the population prehistory of
America
...

Flannery TF
...
Science 1999;293:182–183
...
Archaeology of the dreamtime
...

Gibbons A
...
Science 1996;274:31–32
...
Young ages for Australian rock art
...

Goebell T
...
Evol Anthropol
1999;8:208–227
...
A requiem for North American overkill
...

Greenberg JH, Ruhlen M
...
Sci
Am Nov 1992:94–99
...
The settlement of the Americas
...

Habgood P
...
In: Mellars P, Stringer CB, eds
...

New Haven: Princeton University Press, 1989:232–244
...
Clocking the first Americans
...

———
...

Science 1997;276:754–755
...
The search for the earliest Americans
...

Merriwether DA, Ferrell RE
...
Mol Phylogen Evol
1996;5:241–246
...
Pleistocene extinction of Genyornis newtoni: human
impact on Australian megafauna
...

Morwood MJ, Smith CE
...

Aust Archeol 1994;39:19–38
...
When did humans first arrive in Australia and
why is it important to know? Evol Anthropol 1998;6:132–146
...
The human colonization of Australia
...

Schurr TG
...

Am Scientist 2000;88:246–253
...
American origins
...

Wolpoff M, et al
...
Science
2001;291:293–297
...
For
a long time archeologists assumed when humans began to cultivate
food resources, there followed a shift from nomadic bands to sedentary
communities
...
Two principal hypotheses are offered to explain the shift
to agriculture: one, the result of population pressure; two, a consequence of climatic change
...
Prior to this date, human populations subsisted by various forms of hunting and gathering
...


Figure 35
...
Three
major centers of origin existed, whose
influence spread geographically, eventually
coming to dominate local innovations
...
(See figure 35
...
)
The adoption of agriculture was extremely rapid as measured against the established time scale of human prehistory
and was accompanied by an escalation of the population
size, rising from approximately 10 million at the outset of the
Neolithic to 100 million some 4000 years ago
...
(See figure 35
...
)
Until relatively recently, the Agricultural Revolution was
viewed as a rather straightforwardaif dramaticatransition
...
As a

“Fertile Crescent”:
Meso-America:
Maize, squash, beans, cotton, gourds Wheat, barley, einkorn, lentil, pea
...

Pigs
(7000 years ago)

248 Part Nine: New Worlds
10,000

Agricultural
revolution

Present: 2
...
6

0
...
1% per annum

100

10

20

18

16

14

12

10

8

6

Time (thousands of years ago)

result, these people began living in larger, settled communities, whose social and political complexity far exceeded anything achieved earlier in history
...


New interpretations

4

2

Present

Population (millions)

18th century: 0
...
2 Population change
since the Neolithic: The beginnings of
substantial population growth coincided
with the origin of plant and animal
domestication, igniting an explosion that
continues today
...


Traditional view of Agricultural Revolution

Food domestication

Small nomadic
hunter-gatherer bands

Large sedentary
agricultural community

Current view of Agricultural Revolution

Given the discovery of new archeological and ethnographic
evidence, and with a reassessment of some existing evidence,
the Neolithic transition is now viewed in a different light
...
Hunters and
gatherers of the late Pleistocene, it is now realized, were not
necessarily living the simple, nomadic lifeway that anthropologists had imagined
...
(See figure 35
...
)
The traditional characterization of the Neolithic transition
as an Agricultural Revolution rested on two kinds of evidence: archeological and ethnographic
...
The phrase “Agricultural Revolution” seemed apt for a number of reasonsanot least of which
was the limited amount of archeological data with which to
sketch this crucial period in human history
...

Indeed, the remains of Çatal Hüyük, which was occupied by
farming people between 8500 and 7800 BP, has been
described as an archeological supernova
...
3 Origin seen as more complex: In the traditional
view, sedentism and domestication developed together; small,
nomadic, hunter-gatherer bands were viewed as being transformed
into large, sedentary, agricultural communities
...

Intermediate between small nomadic bands and large, agricultural
communities, therefore, were sedentary communities that subsisted
on hunting and gathering
...
A British team of archeologists, led by Ian
Hodder of Cambridge University, began new excavations at
this site in 1994
...
Such sites
include ‘Ain Ghazal in Jordan and Abu Hureyra in northern
Syria
...
Examination of this more complete
archeological record reveals that the Neolithic transition was
a step-by-step introduction of domestication, not an overnight revolution
...
It was
occupied from 11,500 to 7000 BP, with one major break from
10,100 to 9600 BP
...
A year-round
settlement of simple yet substantial single-family houses,
Abu Hureyra I confounds the traditional view of huntergatherer existence, which posits the existence of small,
nomadic bands
...
It was reoccupied half a millennium later, this time by people who included plantabut not
animaladomestication in their economy
...
The overall pattern, therefore, is “a step by step introduction of domesticated plants
and animals,” explains Yale University’s Andrew Moore,
who led the 1974 excavation
...
”
It should have come as no surprise that late Pleistocene
hunters and gatherers led socially complex livesaindications
of this lifeway have been known from the archeological
record for some time
...
“If one is looking for a single archeological reflection of sociocultural complexity, then presumably attention will continue to focus on
the unique and impressive manifestations of Upper Paleolithic cave art from the Franco-Cantabrian region,” notes
Paul Mellars of Cambridge University
...

More tangible evidence of late Pleistocene social and economic complexity comes from the Central Russian Plain
aspecifically, a site near the town of Mezhirich, 1100 kilometers southwest of Moscow
...
4)
...

Given this and other evidence, it is perhaps surprising that, until relatively recently, late Pleistocene humans

249

Figure 35
...
Individually constructed with great
technical and esthetic attention, these 15,000-year-old dwellings
formed a community that was surely more socially complex than
is usually envisaged for pre-agricultural hunter-gatherer peoples
...
I
...
L
...
Soffer/Scientific
American, November 1984, All rights reserved
...
This characterization was based on a
very important and influential study during the 1960s of the
!Kung San (Bushmen) of the Kalahari
...

The project revealed that, despite living in a marginal
environment, the !Kung were able to subsist on simple hunting and gathering, with the expenditure of just a few hours’
work each day
...

The collective results of the Harvard project were presented
at a landmark meeting, titled “Man the Hunter,” held at the
University of Chicago in 1966
...

For more than a decade, the !Kung model of the huntergatherer lifeway dominated anthropological thought
...
This shift in perception was driven by new historical, archeological, and behavioral ecology evidence
...
“Many characteristics previously associated solely
with farmersasedentism, elaborate burial and substantial
tombs, social inequality, occupational specialization, longdistance exchange, technological innovation, warfareaare to
be found among many foraging societies,” concluded anthropologists James Brown and T
...

In other words, the Agricultural Revolution was recognized to be neither a revolution nor a movement primarily
focused on the adoption of agriculture
...
In some cases, however,
plant domestication preceded sedentism, particularly in the
New World
...
Clearly, the Neolithic was
a complex period, and must have been influenced substantially by both local and global factors
...

Was it carried by farmers moving into the region from the
Middle East? Or did it develop locally, with the idea spreading throughout the continent, not the farming-oriented
people? This question is amenable to genetic as well as archeological research
...
This conclusion, known as the demic expansion
model, has been challenged by a recent survey of mitochondrial DNA patterns throughout the continent
...
The difference of opinion
remains unresolved
...
5 Hypotheses of agricultural origins: Population
pressure and climate change have long vied as the most persuasive
potential candidates for initiating sedentism and domestication
...


of the world, anthropologists have long sought a global
cause
...
(See figure 35
...
)
Although a dramatic rise in population numbers undoubtedly accompanied the Neolithic transition, the question of
whether this relationship was one of cause or effect remains
unanswered
...
He argues that it was causal, and
adduces signs of nutritional stress in skeletal remains from
the late Paleolithic to support his case
...
For these researchers, including Flannery, the population pressure hypothesis remains
unconvincing
...
The shift from glacial
to interglacial conditions would have driven extensive
environmental restructuring, bringing plant and animal
communities into areas where they did not previously exist
...

Moore considers this step to have been important in the early
establishment of Abu Hureyra and other similar settlements
...
Moreover, some
periods earlier than the end of the Pleistocene must have
been conducive to intensification of food production
...
Whereas population pressure and climate change were
both “external” factorsathe first presenting a problem to be
solved, the second an opportunity to be exploitedasocial
complexity would provide an “internal” trigger for change
...
Increasing social complexity, and the
stratified social and economic order that accompany it, place
demands on food production that cannot be satisfied by the
small, nomadic hunter-gatherer society, Bender and her supporters say
...
Bender does not argue that this
internal factor is the sole cause, merely that “technology and
demography have been given too much importance in the
explanation of agricultural origins, social structure too little
...
6
...
It is
analogous to a “black box”: you know it is important, but you
do not understand how it works
...

In fact, modern humans underwent a biological change
between the end of the Pleistocene and the Holocene, but
it affected their bodily physique
...
As Robert Foley of
Cambridge University has recently pointed out, this changed
body size may have implications for how one views the
Neolithic transition
...
These people, whose numbers are rapidly dwindling and who live in the most marginal areas of the globe,
generally include a large plant-food component in their diet
(notable exceptions exist, of course) and live in egalitarian
communities
...


251

Social complexity

Intergroup complexity

Long-distance trade

Material and ritual
culture
Sedentism
Domestication

Day range

Diversity of resources

Population

Figure 35
...
Although these changes have
often been associated exclusively with agricultural societies, it is
now evident that sedentism can, by itself, produce at least part of
this pattern
...
Males may
well have engaged in more heated competition for access to
females (see unit 13), as well as more big-game hunting and
provisioning of their mates and offspring
...
“Rather than
being an adaptation ancestral to food production, it is a parallel development
...
”
Clearly, anthropologists’ picture of the Neolithic transition is far from complete
...

“No single factor is responsible for the rise of cultural complexity,” concluded Brown and Price
...
It may be sufficient
for the moment simply to be aware that things are not what
they have seemed to be
...
The Natufian culture of the Levant, threshold of the
origins of agriculture
...

Bird-David N
...
” Curr Anthropol
1992;33:25–48
...
The ecological genetics of domestication and
the origin of agriculture
...

Byrd B
...
J Archeol Res
1994;2:221–253
...
Origin of agriculture at Kuk Swamp in the highlands of New Guinea
...

Diamond J, Bellwood P
...
Science 2003;300:597– 603
...
Guila Naquitz
...

(Papers on the research project in the Valley of Oaxaca, Mexico
...
Hominids, humans and hunter-gatherers: an evolutionary
perspective
...
Hunters and
gatherers: history, evolution and social change
...

Hawkes K, O’Connell J
...
Curr Anthropol 1992;33:63–66
...
Nimrods, piscators, pluckers and planters: the origins of
food production
...

Layton R, et al
...

Curr Anthropol 1991;32:255–274
...
The cradle of agriculture
...

Molleson T
...
Sci Am Aug
1994:70–75
...
Causes of early human population growth
...

Piperno DR, Stothert KE
...
Science 2003;299:1054–1057
...
Last hunters, first farmers
...

Richards M, et al
...
Am J Human Gen 1996;59:185–203
...
The earliest farmers in Europe
...


GLOSSARY

Absolute dating: techniques that provide information
about age by a physical measurement of the material at the
site in question, such as radiometric dating
...
)
Acheulean: name applied to a type of stone-tool industry
characterized by large bifaces including handaxes; it began
approximately 1
...

Adaptation: the process by which a species changes through
natural selection, becoming well suited to its environment
...
Combinations of alleles that
confer high fitness will be seen as peaks on the landscape;
those conferring lower fitness will be seen as valleys
...

Allele: alternative form of a gene (for example, different eye
colors); all genetic loci comprise two alleles, whose effects
may differ depending on whether they are identical or different
...
)
Allen’s rule: populations of a geographically widespread
species living in warm regions will have longer extremities
than those inhabiting cold regions
...
)
Allopatric speciation: speciation via geographically separated populations
...

Anagenesis: evolution by gradual change within a lineage
...
(Contrast with homology
...

Arboreal: tree-living
...

Autapomorphy: a derived character not shared with other
species
...
(See Allen’s
rule
...

Biogeography: a perspective of patterns in biology related
to their geographical context
...

(Contrast with phylogenetic species concept
...

Bipedality: upright walking on the two hind legs (for
example, humans’ habitual mode of locomotion)
...

Calvarium: the cranium minus the face
...

Carbon-14 dating: an absolute dating method, based on the
decay of the radioactive isotope of carbon, carbon-14
...

Catastrophism: the theory that the Earth’s geological features were formed by a series of catastrophic events, such
as floods, during Earth’s history
...

Chatelperronian: the stone-tool industry apparently associated with late Neanderthals
...

Cladistics: the school of evolutionary biology that seeks
relationships among species based on the polarity (primitive or derived) of characters
...


254

Glossary

Cladogram: a diagrammatic representation of species relationships
...
)
Classification: arrangement of organisms into hierarchical
groups
...

Convergent (or parallel) evolution: the result of natural selection producing similar adaptations in separate
lineages
...

Culture: the sum total of human behavior, including technological, mythological, esthetic, and institutional activities
...
(Contrast with primitive character
...

Dominance (allelic): an allele A is dominant if it is
expressed as the phenotype when in the presence of a
second allele, a
...
(See recessive allele
...

Electron spin resonance: a technique of absolute dating
that is based on natural radiation in the soil affecting the
state of electrons in a target material, such as teeth
...

Encephalization quotient: a measure of relative brain size
...

Eurybiomic: the ability of a species to utilize food resources
from several different biomes
...

Exons: the segments of genes that code for protein sequence
...
)
Faunal correlation: a method of relative dating based on
species reaching a similar evolutionary stage at the same
time in history in different geographical localities
...

Founder effect: the formation of a new population when a
sub-population becomes isolated from the parent population
...

Frugivore: a fruit-eating animal
...

Genetic drift: random changes in gene frequencies in a
population
...

Genotype: the genetic profile of an individual
...


Group selection: selection acting between groups of individuals, rather than between individuals
...
(See homozygous
...

Hominoidea: all living and extinct species of humans and
apes
...
(Contrast with analogy
...
(See analogy
...
(See heterozygous
...

Intermembral index: a comparison of the length of the
upper and lower limbs
...
(See exons
...

K-selection: the life-history strategy in which species have a
low potential reproductive output
...

Life-history variables: features such as age at weaning, age
at sexual maturity, and longevity, which determine the
nature of a species’ overall life
...

Macroevolution: evolution at the scale of important
innovations
...

Microevolution: evolution within lineages
...

Middle Stone Age: the second stage of the Stone Age;
applied to Africa
...

Mitochondrial genome: the package of genetic material
within mitochondria
...

Molecular systematics: the use of molecular biological
data for classification and systematics
...

Morphology: the physical form of an organism
...

Multiregional evolution hypothesis: the hypothesis that
modern humans evolved in near concert in different parts
of the Old World
...

Natural selection: the process by which favored variants in
a population thrive
...

Neolithic: the New Stone Age, usually associated with the
beginning of agriculture, some 10,000 years ago
...

Niche: the role in the ecosystem played by a species
...

Oldowan: the stone-tool industry characterized by flakes
and chopping tools produced by hard-hammer percussion
of small cobbles; it began 2
...

Ontogeny: the process of growth and development of an
individual from conception onward
...

“Out of Africa” hypothesis: the hypothesis that modern
humans originated recently in Africa; based on fossil
evidence
...

Paleomagnetism: magnetism induced in volcanic rocks as
they cool, recording the direction of the Earth’s prevailing
magnetic field at the time
...

Paraphyletic group: a set of species containing an ancestral
species and some, but not all, of its descendants
...

Phenetic classification: a method of classification in which
species are grouped together on the basis of morphological
similarities
...

Phyla: major body plans
...


255

Phylogenetic species concept: a species is the smallest
diagnosable cluster of individual organisms displaying a
parental pattern of ancestry and descent
...

Polarity: the assessment of a character as either primitive or
derived
...

Polyphyletic group: a set of species deriving from more
than one common ancestor
...

Postorbital constriction: the narrowing of the skull immediately behind the forehead
...

Primitive character: a character that was present in a common ancestor of a group and is therefore shared by all
members of that group
...
)
Prognathism: a jutting forward of the face and jaw
...

Provenance: the location of a fossil or artifact in the prehistoric record
...

Radiometric dating: absolute dating, based on the known
decay rate of radioisotopes
...
(Contrast with dominance
...

Regional continuity: a prediction of the multiregional
evolution hypothesis that certain morphological features
will be characteristic of particular geographical locations,
and will be present from early Homo erectus times through
the emergence of modern Homo sapiens
...
(Contrast with absolute dating
...

Sexual dimorphism: the state in which some aspect of a
species’ anatomy consistently differs in size or form
between males and females
...


256

Glossary

Speciation: the evolutionary splitting of a lineage to produce two daughter species
...

Species tree: the population history of lineages that derive
from a common ancestor
...

Sympatric speciation: speciation in a subpopulation whose
range overlaps with that of the parental population
...

Synapomorphy: a shared derived character
...


Taphonomy: the study of the processes by which bones
become fossilized
...
taxa): any named group, such as species, genus,
or family
...

Thermoluminescence dating: a method of absolute dating
based on the influence exerted by natural radiation in the
ground on electrons within a target material
...

Uniformitarianism: the theory that the Earth’s geological
features are the product of small changes over long periods
of time
...

Valgus angle: the angle subtended by the femur from the
knee to the hip
...
(propliopithecids), 104
Africa
Acheulean handaxes, 166–7, 168–9
agricultural revolution, 151
antelopes, 26

anthropoids, 103, 104
archeological evidence, 208, 211–13
archeological time periods, 151–2
australopithecine sites, 125, 132
Bushmen, 232–3, 249
catarrhines, 103
as cradle of mankind, 12, 187–8, 196–8
cultural change, 151
gorillas, 81
habitats, 70
hominins, 16, 26
hominoids, 103, 104–8, 114, 119
Homo erectus, 159, 160–2
Homo sites, 144
human behavior, 213
human fossils, 187, 188–9, 196–7
mammals, 28
migrations, 25, 211, 239
Nilotic people, 69–70
plate tectonics, 25, 26
primates, 60
regional continuity, 196–7
speciation events, 159
stone tools, 151
see also East Africa; out-of-Africa
hypothesis; South Africa; subSaharan Africa
African apes, 87
anatomy, 95, 96, 105
behavioral traits, 88–9
brow ridges, 49
classification, 49–50, 54, 95, 100, 101
dentition, 95
genetic distances, 97, 98
and human evolution, 3, 12, 13, 14–16
locomotion, 62
origins, 88, 99–100
social behavior, 88–9
social organization, 89–90
tooth enamel, 95, 100, 119
Africans, mitochondrial DNA variations,
201, 202

Afropithecus spp
...
(parapithecids), 104
Algeripithecus minutus (anthropoid), 65, 104
Alice Through the Looking Glass, 24
alleles
coalescence times, 202
definition, 19
dominant, 19
and natural selection, 20
recessive, 19
Allen’s rule, 69, 70
Allia Bay (Kenya), 125, 127
alliances, primates, 220, 221
allopatric speciation, 24, 27
mechanisms, 21
Altamira (Spain), 233
Altiatlasius koulchii (primate), 65
altriciality, 217, 218
secondary, 78
strategy, 78
Alu sequences, 203–4
definition, 204
Alvarez, Luis, 32

258

Index

Ambrona (Spain), 168
American Museum of Natural History, 5, 7,
8, 21, 146
Americas
colonization, 53, 239– 43
hunter-gatherers, 73
Ice Age, 239–40, 241, 242–3
migrations, 25, 159, 240
see also North America; South America
Amerind language, 241
Amerindians, 241
amino acid racemization dating, 42
amino acids, protein sequencing, 97
amniote eggs, 30
amphibians, brain size, 217
Amphipithecus spp
...
, 137, 143– 4, 162– 4
humans, 96, 137
see also brain; cranium; dentition; feet;
hands; jaws; limbs
ancestral suite, 89
Andrews, Peter, 95
Andrews, Roy Chapman (1884–1960),
5, 8
animal bones
pendants, 226
and stone tools, 170
as tools, 208, 209
Animalia, 45
animals
behavior, 80
body size reduction, 73
domestication, 247, 249, 250
and humans compared, 3– 4
in prehistoric art, 230, 232, 233
Ankarapithecus spp
...
(parapithecids), 104
Arago cave (France), 168, 194
Aramis (Ethiopia), 127
arboreal theory, 63, 64
arboreality, australopithecines, 133–4, 136,
137
archeological evidence, 208–14
African, 211–13
Asian, 211
background, 208–9
European, 209–11
archeological time periods, regional
differences, 151–2
archeology, and evidence, 10
Arctic, 69
ice growth, 27

Arcy-sur-Cure (France), 181, 210
Ardèche (France), 230
Ardipithecus Kadabba, 124
Ardipithecus ramidus (hominin), 125, 135,
149
adaptive radiations, 124–5
characteristics, 124–5
dentition, 100, 117, 124–5
discovery, 124, 127
phylogeny, 148, 149
Arensburg, Baruch, 224
Argentina, 240
argon-39/argon-40 dating, 41
Aristotle (384–322 BC), 4
Arizona State University (USA), 233
arm length, 107
Armidale (Australia), 72
Armstrong, Este, 219
Arnhem Land (Australia), 244
arrows, 230, 232
art
and cognitive ability, 225–6
and language, 225–6
meaning of, 229
objects, 211
portable, 230, 233, 249
shamanistic, 232–3
trance-induced, 232–3
see also engraving; painting; prehistoric art
artistic expression, 226, 227, 229–30
symbolic, 212, 233, 234, 248
Asfaw, Berhane, 126
Asia
Acheulean handaxes, 166, 168
anthropoids, 104
archeological evidence, 208, 211
as cradle of mankind, 12, 13, 121
hominoids, 103, 107
Homo erectus, 159, 160, 161, 162, 187
human behavior, 213
migrations, 25, 211, 239
Neanderthals, 179, 183
primates, 60
see also Eurasia; Southeast Asia
Asian great apes, 12
asteroids, 32, 33
Atapuerca (Spain), 194–5
Atlantic, 239
Aurignacian technology, 181, 209, 210, 211,
233–4
aurochs, 230
Australasia, regional continuity, 189–91
Australia
colonization, 190, 243–5
human fossils, 190, 244–5
hunter-gatherers, 73
Ice Age, 243–4
marsupials, 25
migrations, 159, 211, 240

Index
regional continuity, 190
rock paintings, 42
Australian National University, 187
Australian Rock Art Association, 234
Australians, 72, 73
modern, 190
see also Aborigines
australopithecines, 131–9, 136, 144
adaptive radiations, 125
African sites, 125, 132
anatomy, 96, 131–2, 135–7
arboreality, 133– 4, 136, 137
behavior, 132–5
biology, 137
bipedalism, 132–5
body weight, 135
brain organization, 219
brain size, 131, 135, 143, 218
characteristics, 131, 136
cranium, 121, 131, 132, 133, 138
dentition, 116, 131–2, 135– 6
diet, 88, 90, 137
discovery, 121–4
evolution, 184
extinction, 131
fossils, 148
gracile, 122, 123, 135– 8, 245
habitats, 122, 131, 137
jaws, 88, 97, 126, 135– 6
and language, 222
locomotion, 132–5, 136–7
phylogeny, 131, 148, 149–50
stature, 135
taxonomic issues, 131
tool making, 138, 151, 155– 6
tooth eruption patterns, 118, 119
tooth wear patterns, 137
vocal tract, 223
see also robust australopithecines
Australopithecus spp
...
(hominins)
Australopithecus rudolfensis see Homo rudolfensis
autapomorphies, 48

259

baboons, 60
fingernails, 47–8
as hominin models, 87, 88
locomotion, 96
sexual dimorphism, 85
social behavior, 87
social organization, 81, 85
Bacho Kiro (Bulgaria), 195, 234
baleen whales, 60
bamboo, 168
Baringo, Lake (Kenya), 107
Barlow, F
...
, 16
basicranial flexion, 223–4
basicranium, 110, 113, 121, 124, 131
shape, 223
traits, 147, 150
Batadomba Iena cave (Sri Lanka), 211
batons, 230
bats, 60
beads, 152, 209
Bednarik, Robert, 234
Begun, David, 96
behavior
animal, 80
artistic, 212
australopithecines, 132–5
changing patterns of, 164–5
evolution, 213
modern, 212–13
Neanderthals, 181–2
see also hominin behavior; social
behavior
behavioral ecology
and body size, 75–9
and brain size, 75–9
models of hominin behavior, 87, 89–90
traits, 78
behavioral evolution, 211
issues, 208
behavioral traits, 19, 88–9
Behrensmeyer, Anna K
...
, 143–4
see also anatomy; sociobiology
biomes, 26, 28
biotic crises, 32, 34
bipedal apes, 23

260

Index

bipedalism, 7, 8, 10, 16
anatomical adaptations, 111
australopithecines, 132–5
biomechanics, 109–10
causes, 109, 113
development, 188
energetics, 112–15
hominins, 100, 125
hominoids, 107, 113
humans, 62, 96
origins, 21, 109–15
ecological context, 110
theories, 110–12, 127
phases, 109–10
vs
...
, 69, 140, 162–3

humans, 251
increase, 21
and life-history variables, 75–9
mammals, 77, 78
and metabolic rate, 64
Neanderthals, 69, 70
and nutritional stress, 73
primates, 60, 64
reduction, 73
sexual dimorphism, 80, 81, 84, 85
hominins, 90, 162–3
species differences, 76
body temperature, 114
body weight
australopithecines, 135
hominins, 135
Neanderthals, 180
Boker Tachtit (Israel), 211
bone points, barbed, 212
bone tools, 208, 209, 212
australopithecines, 138
bones
cutmarks, 173–5, 182
defleshing, 173–5, 240
disarticulation, 56, 58, 173
fossilization, 56–7
marks on, 58
weathering, 57
see also animal bones
bonobos see pygmy chimpanzees
Border Cave (South Africa), 188, 197
Bordes, François, 181
Boston University (USA), 7
Boule, Marcellin, 183, 184
Boxgrove (UK), 194
Brace, C
...
K
...
, 21–2, 119, 143, 218, 219
issues, 7, 164
and social organization, 220
brain-first theory, 13, 14
brain size
australopithecines, 131, 135, 143, 218
and behavioral ecology, 75–9
and body size, 217, 218
catarrhines, 104
evolution, 217–21, 227
factors affecting, 217
and gestation periods, 217, 218
hominins, 18, 22, 126, 217
Homo spp
...
(propliopithecids), 104
Catopithecus browni (propliopithecid), 104
cats, 63
Caucasus, 186
Cave, A
...
, 184
cave paintings, 210, 212, 229, 249
dating methods, 39, 232
and hunting-magic hypothesis, 232

images, 230
interpretation, 230–3
see also rock paintings
caves, 44, 182
hominin fossils in, 57, 192, 193, 194
cells
metabolism, 200
structure, 200
Cenozoic, 26, 31
central-place foraging hypothesis, 174–5
Central Russian Plain, 249
Cercopithecoidea, 97, 103
see also Old World monkeys
cercopithecoids, 104
species diversity, 105
cereals, 249, 250
cetaceans, brain size, 217–18
Chad, 26, 125, 126
Chain of Being, 4, 5
chameleons, 63
character states, 47–8, 50, 53
charcoal, 42
Chase, Philip, 233, 234
Chatelperron (France), 181, 182
Chatelperronian technology, 181, 182,
210–11
Chauvet Cave (France), 230, 232, 233
Chemeron formation (Kenya), 143, 145
Cheney, Dorothy, 221
chewing
anatomy of, 136
traits, 147, 149, 150
see also dentition
Chicago (USA), 61, 141, 170, 249
University see University of Chicago (USA)
childhood, extended, 165
Chile, 240
chimeras, 233
chimpanzee–human continuum, 87–8
chimpanzee/gorilla alliance, 98, 99
chimpanzees, 4, 12
anatomy, 96
basicranium, 113
behavioral traits, 88
bipedalism, 109, 113, 134
brain size, 131, 218
brow ridges, 48–9, 50
classification, 49, 54, 95, 100, 101
cranium, 20, 133
dentition, 132
diet, 114
energetics, 114
feeding strategies, 114, 115
fingernails, 47–8
foraging, 114
foraging range, 114
as hominin models, 87, 88
hunting, 111
jaws, 97, 117, 136

261

knuckle-walking, 62, 100, 110, 113
larynx, 224
locomotion, 62, 134–5
mitochondrial DNA, 200
origins, 9
pelvis, 112
sexual dimorphism, 81
social behavior, 87
social organization, 80, 81, 82, 83–4, 84,
90
studies, 87
teeth, 119
testes, 90
tooth enamel, 119
toothwear patterns, 120, 137
vocal tract, 224
see also pygmy chimpanzees
China
anthropoids, 104
hominoids, 107
Homo spp
...
Desmond, 151
classification systems, 4, 45
issues, 46
philosophies, 46–7
see also systematics
claws, 62
cleavers, 166, 167, 169
climate, 180
and body size, 73
cycles, 26–7
Miocene, 107

262

Index

climate change, 143
and extinction, 24, 27, 243
global, 24, 26–7, 32, 73
and hominin evolution, 27
Ice Age, 73
and migration, 27– 8
Miocene, 114
and Neolithic transition, 250–1
responses, 26–9
and speciation, 24, 27
and topographic diversity, 28, 27
climatic adaptation, humans, 69–70
climbing, 104, 110, 134
Clovis culture, 239, 240, 242, 243, 244
Clovis points, 242, 243
Clutton-Brock, Tim, 75– 6
Côa River (Portugal), 230
coalescence times (CTs), 204
definition, 202
distribution, 203
mechanisms, 202–3
studies, 203
cognitive ability, 217
and art, 225–6
primates, 221
tool makers, 220
cognitive function, 208
Cohen, Mark, 250
Collard, Mark, 145
colobus monkeys, 60, 127
colonization, 239–46
Americas, 53, 239– 43
Australia, 190, 243–5
colugos, 65
Columbia University (USA), 219
Columbus, Christopher (1451–1506),
241
comparative analysis, 63
competition
for females, 73, 80, 84, 90
groups, 32, 80, 83
primates, 78
computer simulations, 53, 114
of mass extinctions, 32–3
computerized tomography (CT), 119, 135,
137
Congo see Zaire
Conkey, Margaret, 233
Conroy, Glenn, 119, 135
consciousness, 221, 226
continental drift see plate tectonics
convergent evolution
issues, 50
and natural selection, 19
cooperation, 170
groups, 83
male–male, 163
see also food-sharing hypothesis
Copernicus, Nicolaus (1473–1543), 3, 5
Cordilleran ice sheet, 239

cores, 151, 153, 209
manufacture, 154, 167, 172
prepared, 152, 208
Cosquer Cave (France), 230
cradle of mankind, 12
Asia as, 13, 121
see also out-of-Africa hypothesis
Cramer, Douglas, 88
cranium
anatomy, 107
apes, 96
australopithecines, 121, 131, 132, 133, 138
brain convolutions, 218
and brain size, 218
hominins, 57, 121, 123, 123, 148
hominoids, 107
Homo spp
...
, 116, 140, 143
primates, 62
sexual dimorphism, 117
traits, 147, 149, 150
see also teeth; tooth enamel

Index
developmental strategies, altricial vs
...
, 164, 166
hunter-gatherers, 251
primates, 64, 80, 81, 114
see also meat-eating
dietary resources, 84, 90, 217
and bipedalism, 112–13, 114
and climate change, 114
distribution, 114
management, 220
sharing, 170
and stone tools, 154
see also food
differential reproductive success see natural
selection
digging sticks, 153, 154, 156
dinosaurs, 9
extinction, 32, 34
species diversity, 34
discoids, 153, 154
Disotell, Todd, 107
divergence, 53
DNA sequences, 51, 97– 8, 202
Dmanisi (Georgia), 161
DNA
ancient, 107
genetic coding, 101, 200
humans, 186
mutation rates, 50, 200
Neanderthals, 186, 204
restriction enzyme mapping, 97
see also Alu sequences; microsatellites;
mitochondrial DNA; nuclear DNA
DNA–DNA hybridization, 50, 53, 97
DNA sequences, 20, 50, 53, 97, 98
convergence, 51
divergence, 51, 97– 8, 202
dogs, forelimbs, 47
domestication, 247, 249, 250
Dowson, Thomas, 232–3
Draa, River (Morocco), 234
Dryopithecus spp
...
(fossil ape), 107
Dubois, Eugene (1858–1940), 159, 160, 183
Duke University (USA), 60, 137, 223
Primate Center, 104
Dunbar, Robin, 221, 226–7
Durant, John, 10
Düssel River (Germany), 182
Earlier Stone Age (ESA), 151
stone tools, 152, 169

Early Pleistocene, hominins, 187
Earth
age of, 5, 53
climate cycles, 26–7
extraterrestrial impacts, 32, 33
magnetic polarity reversals, 40
plate tectonics, 24–6
East Africa, 143
archeological evidence, 208
australopithecines, 122–4
habitats, 70, 90
hominin fossils, 15, 16, 41, 123–6
Homo erectus, 160–1
plate tectonics, 26
East Asia
archeological evidence, 208, 211
regional continuity, 191–2
Ecuador, 247
Egypt, anthropoids, 104
Elandsfontein (South Africa), 197
Eldredge, Niles, 6, 10, 21
electron spin resonance dating, 39, 42–4,
188, 212
electrons, 42
electrophoresis, proteins, 97
elephants, 31, 60, 169, 225
and faunal correlation, 39
reproduction, 75
elk, 242
embryological development, 20, 100
Emory University (USA), 242
encephalization, 7, 8, 22, 78, 218
traits, 147, 149, 150
see also brain size
encephalization quotient (EQ), 218
energy
bipedalism, 112–15
demand, and body size, 76–7
efficiency, 113–14
energy-efficiency hypothesis, 113–14
England, 132
stone tools, 168
engraving, 210
cognitive ability, 225
prehistoric, 229, 230, 233
entoptic images, 232–3
Eocene, anthropoids, 104
Eosimias spp
...
(hominoids), 107
erosion, 5
ESA see Earlier Stone Age (ESA)
Eskimos, 69, 70, 72
Ethiopia
australopithecines, 138, 147
brain cases, 188, 189, 197
hominin fossils, 57, 109, 123, 126
human fossils, 188–9, 197
plate tectonics, 26
stone tools, 152–3, 166–7, 211

263

Eurasia
archeological time periods, 151
catarrhines, 103
hominoid migration, 104
hominoids, 104–5
humans, 197
migrations, 25, 26, 239
stone tools, 151, 152
Europe, 72
Acheulean handaxes, 168
archeological evidence, 208, 209–11
climate, 180
Homo erectus, 159
human behavior, 213
Ice Age, 70, 249
Neanderthals, 179, 183
plesiadapiforms, 65
prehistoric art, 229–30, 234
regional continuity, 193–6
rock paintings, 42
stone tools, 151
eurybiomic species, definition, 28
Eve see mitochondrial Eve hypothesis
evolution
and adaptation, 10
behavioral, 208
biotic context, 24
hypotheses, 126–7
modes of, 22
mosaic, 109
parallel, 15, 19, 147
physical context, 24–9
and plate tectonics, 24–6, 104, 106
as progress, 5–6
unilinear, 183, 184, 186
see also brain evolution; convergent
evolution; hominin evolution;
human evolution; macroevolution;
microevolution
evolutionary change, determinants, 21–3,
24
evolutionary hypotheses see evolutionary
theories
evolutionary patterns
and anatomy, 162–4
and dating issues, 161–2
and extinction, 30–5
evolutionary ratchet, use of term, 221
evolutionary relationships, hominins,
146–50
evolutionary success, measures, 76
evolutionary systematics, 46
evolutionary theories, 99–100
history, 3– 6, 12–17
modern, 18–23
modern synthesis, 20
see also mitochondrial Eve hypothesis;
multiregional evolution hypothesis;
out-of-Africa hypothesis; singleorigin hypothesis

264 Index
evolutionary trees, 22, 23
construction, 53
hominins, 22–3, 149
see also cladograms
exogamy, 88–9
exotic stone, 209
extinction, 4–5, 18
australopithecines, 131
and climate change, 24, 27, 243
determinants, 22
and evolutionary patterns, 30–5
mammals, 245
profiles, 244
rates, 32
resistance, 33
see also mass extinctions
extraterrestrial impacts, 32, 33
eyes, 62
color, 19
divergent, 63
faces, 126
engraved, 230
size reduction, 72
traits, 150
Falk, Dean, 219, 222
families, 45
farmers, 73
migration, 250
farming see agriculture
faunal correlation, 39, 122, 161
favorable traits, 18
Fayum Depression (Egypt), 104
feeding strategies, 114, 115
feet
anatomy, 96, 133, 136, 137
grasping, 61–2, 63, 64, 110
Feldhofer Grotto (Germany), 182, 183
Feldhofer specimen (Neanderthal), 182,
183, 186
feldspar, 41
femaleness, in art, 232
females, competition for, 73, 80
Fertile Crescent, 247, 248–9
fetus, 90, 220
neoteny, 20
Field Museum (Chicago), 61, 73, 141, 217
figurines, 234
fingernails, 47–8, 50, 62
fingers, 60, 135, 138, 156
fire, early use of, 165
fish, in prehistoric art, 230, 233
fission–fusion social system, 90, 114
fission track dating, 42
flake tools, 58, 166, 174, 180
manufacture, 151, 153, 154, 155, 167,
208–9
retouched, 209
Flannery, Kent, 250

flight, evolution, 30
flints, dating methods, 39
floods, 4–5
Florisbad (South Africa), 197
flowers, 233
climate-driven changes, 250–1
flutes, 209
Foley, Robert A
...
(hominoids), 107
glaciation, 250
glass, dating methods, 42
globin genes, 52, 98
goats, 249
God, and creation, 3– 4, 5
Gona region (Ethiopia), 138, 152
Goodall, Jane, 87
Goodman, Morris, 15, 97, 98
model, 100–1
Gorilla spp
...
, 107
Gravettian technology, 209, 210, 233– 4
grazers, 28
toothwear patterns, 120
Great American Interchange, 25– 6
great apes
classification, 15, 46, 54, 95
locomotion, 62
Great Rift Valley (Africa), 26, 125, 126
Greece, 107, 194
Greenberg, Joseph, 241, 242
Gregory, William King (1876–1970), 7, 13,
14
grinding stones, 212
Grine, Frederick, 137, 150
groups
advantages, 80, 81–2
competition, 32, 80, 83

cooperation, 83
female-bonded, 83–4
foraging, 114
matrilocal, 83
monophyletic, 48, 49
non-female-bonded, 83–4
paraphyletic, 48
polyphyletic, 48
vs
...
(hominoids), 106
Hell Gap culture, 242
Hennig, Willi (1913–76), 48
heritability see inheritance
hero myths, 7–8, 9
Herto (Ethiopia), 189, 197
heterozygous, 19, 98
Hexian (China), 191
Himalayas, plate tectonics, 25, 27
hindlimbs, 60, 62, 63, 134–5
Hinton, Martin, 13
histone genes, 52
Hodder, Ian (1949– ), 248
holes (electronics), 42

Holloway, Ralph L
...
, 123
African sites, 144
anatomy, 136, 137, 143– 4, 162– 4
biology, 143–4
body proportions, 175
body size, 69, 140, 162–3
brain expansion, 21–2, 90, 119, 143, 218,
219
brain lateralization, 220
brain size, 71, 131, 140, 141, 143
classification, 101, 159
cranium, 122, 141, 143, 160, 162
dating issues, 161–2
dentition, 116, 140, 143
diet, 164, 166
discoveries, 140–3

earliest, 143
early, 140–5
evolution, 159, 168
fossils, 122–3, 140–5
language, 222, 224
lifestyle, 163
migrations, 239
origins, 122, 126
phylogeny, 148, 149, 150
skeletal robusticity, 71
species diversity, 103
taxonomic issues, 144–5
tool making, 138, 151, 155–6
tooth eruption patterns, 119, 164
tooth wear patterns, 143
Homo antecessor, 194, 195
Homo caudatus, characteristics, 4
Homo erectus, 188, 200
Acheulean handaxes, 166–9
anatomy, 100, 160, 162–4
behavior patterns, 164–5
body size, 162–3
brain lateralization, 220
brain size, 90, 161, 218
changing position of, 159–65
characteristics, 190
classification, 160, 162
cranium, 160–1, 162, 191–2, 197
dating issues, 161–2
descent, 187
diet, 111, 164, 165
discovery, 122, 159–61
evolution, 16, 140, 187, 201–2
fossils, 56, 121, 191, 194
geographical distribution, 159, 161
migrations, 159, 161, 167–8
mitochondrial DNA, 201
origins, 203
population explosion, 206
primitive traits, 191, 192
stature, 70, 78, 161, 162
taxonomic issues, 141
teeth, 90, 164, 190
tools, 156
tooth eruption patterns, 118–19, 164
toothwear patterns, 120
see also Nariokotome boy; Pithecanthropus
erectus (Java Man)
Homo ergaster
Acheulean handaxes, 166–9
anatomy, 162–4
behavior patterns, 164–5
body size, 162–3
brain lateralization, 220
brain size, 163–4, 218
characteristics, 144
classification, 159, 162
diet, 164, 165
discovery, 141–2, 186

evolution, 143
infant care, 220
language, 223
larynx, 223
migrations, 159, 168
spinal cord, 223
teeth, 164
Homo habilis, 126, 142
anatomy, 144
basicranium, 223
body size, 162
brain size, 218
characteristics, 144
classification, 159
discovery, 122, 140
taxonomic issues, 140, 141, 142, 143,
144–5
Homo heidelbergensis, 195
classification, 194, 197
Homo helmei, 197
Homo neanderthalensis
characteristics, 183
see also Neanderthals
Homo rudolfensis, 140
basicranium, 223
brain size, 218
classification, 159
jaws, 143
language, 222
taxonomic issues, 123, 143, 144–5
Homo sapiens, 12
and agriculture, 251
altricial strategy, 78
anatomy, 163
archaic, 72, 164, 182, 191, 194, 195, 200
replacement, 205
bipedalism, 109
body size, 69
brain lateralization, 220
brain size, 63, 164, 218
characteristics, 3
classification, 4, 6, 159, 183
evolution, 3, 34, 187
as evolutionary goal, 5, 7, 9–10
as hero, 7, 9
jaws, 116
language, 222, 225
larynx, 223
life-history factors, 78
origins, 13, 16, 121, 159, 187
teeth, 119
testes, 90
see also humans
Homo troglodytes, characteristics, 4
homogeneity hypothesis, 245
homology, 19, 45, 147, 225
principles, 47–8
homoplasy, 48, 95, 148, 149, 150
homozygous, 19, 98

Index
Hoppius, Christian Emanuel (b
...
scavenging, 111, 170–5
hunting-magic hypothesis, 232
Hutton, James, 5, 31
Huxley, Julian Sorell (1887–1975), 6
Huxley, Thomas Henry (1825–95), 6, 12, 13,
15, 95
Evidences as to Man’s Place in Nature (1863),
3, 63
evolutionary theories, 65
hyenas, 56, 58
in prehistoric art, 230
toothwear patterns, 120
Hylobates spp
...
groups, 80
Indonesia, 73, 159
infant care, 218, 220
inheritance
maternal, 200
mechanisms, 200
patterns of, 201
Insectivora, 45
insectivores, 65
Institute of Human Origins (IHO), 133
intelligence
and brain size, 63
creative, 221
Machiavellian hypothesis, 221
measures, 220
social, 221
intermatch distribution analysis, 205
intermembral index, 107
International Code of Zoological Nomenclature, 46
Inuit, 69, 70, 72
iridium, 32
Isaac, Glynn L
...
, 161, 162, 168, 190
human fossils, 188, 190, 191
regional continuity, 190–1
Java Man see Pithecanthropus erectus
(Java Man)
jaws, 56, 98
anatomy, 97, 116–17
australopithecines, 88, 97, 126, 135– 6
evolution, 30, 116–20, 147
hominins, 97, 124–5, 126
Homo spp
...
, 192
Kanapoi (Kenya), 125, 127
Kanzi (pygmy chimpanzee), 155
Kapthurin Formation (Kenya), 211–12
Katanda (Zaire), 212
Kay, Richard, 137
Kebara (Israel), 180–1, 182, 192, 193, 224
Keeley, Lawrence, 153– 4, 169
Keith, Sir Arthur (1866–1955), 5, 16
evolutionary theories, 7, 8, 13, 15
Kent State University (USA), 111, 132–3,
134
Kenya
hominin fossils, 16, 109, 118, 123– 4, 125,
126
hominoids, 105–7
fossils, 105
Homo spp
...
(hominoid), 107
Kenyapithecus africanus (hominoid), 107
Kenyapithecus rudolfensis see Homo rudolfensis

Kenyapithecus wickeri (hominoid), 107
King, William, 182–3
Klasies River Mouth Cave (South Africa),
188, 197
Kleiber’s curve, 77
Klein, Richard, 211, 213, 226
knee joints, 110, 112
knives, 168, 169, 209
KNM-ER 406 fossil, 122–3, 124, 186
KNM-ER 1470 fossil, 123, 141, 142, 143, 144,
145, 220
KNM-ER 1813 fossil, 141, 142, 144
KNM-ER 3733 fossil, 161, 162, 186
anatomy, 161, 163
KNM-ER 3735 fossil, 145
KNM-ER 3883 fossil, 162
KNM-ER 3884 fossil, 197
KNM-WT 15,000 fossil, 161, 162
see also Nariokotome boy
KNM-WT 17,000 fossil, 138, 147
knuckle-walking, 95, 96, 100
chimpanzees, 62, 100, 110, 113
Koenigswald, G
...
Ralph von, 160
Konso (Ethiopia), 138
Konso-Gardula (Ethiopia), 166
Koobi Fora (Kenya), 153–4, 161, 162, 171,
174, 197
finds, 142, 163, 186
Kow Swamp (Australia), 245
Kromdraai (South Africa), 122
K-selection, 75, 76, 78
!Kung San Bushmen, 249–50
La Chapelle-aux-Saints (France), 182, 183,
184, 224
La Ferrassie (France), 180, 182, 226
La Marche (France), 230
La Quina (France), 226
labyrinth, 181
Laetoli (Tanzania), 127
Lahr, Marta Mirazón, 191, 192, 197–8
Laitman, Jeffrey, 222–3, 224
Lake Baringo (Kenya), 143
lakes, 242–3
Laming-Emperaire, Annette, 232, 233
Landau, Misia, 7, 8, 10
language
acquisition, 224
archeological evidence, 225–6
and art, 225–6
and brain organization, 226
evolution, 222–8
determinants, 226–7
fossil evidence, 222–3
functions, 226
Native Americans, 241
and Neanderthals, 180–1, 223–4
origins, 226
and paleoanthropology, 10

and social interactions, 226–7
and tool-making ability, 155, 225
see also speech
Lankester, Ray, 16
Lantian (China), 161, 191
Laplace, G
...
, 163
hunter-gatherers, 15, 248, 249–50
Neanderthals, 179
limbs
anatomy, 95, 133
forelimbs, 47

Index
hindlimbs, 60, 62, 63
leg length, 107, 135
lower, 110
size and shape, 69
Limnopithecus legetet (fossil ape), 106
Lindly, John, 211, 233
lineage, maternal, 202
linguistic ability, 213
Linnaean classification, 45– 6
Linnaeus, Carolus (1707–78), 46
Systema Naturae (1736, 1758), 4
lions, 88, 242
Liujiang (China), 188
locomotion
apes, 62, 96
australopithecines, 132–5, 136–7
climbing, 104, 110, 134
energetics, 114
hindlimb-dominated, 62, 63
hominoids, 105, 107
modes, 62, 104, 125
orthograde, 105
primates, 62
pronograde, 105
upright, 13, 14, 109
see also bipedalism; knuckle-walking;
quadrupedalism; walking
Longgu Cave (China), 230
lorises, 60, 63
Los Toldos Cave (Argentina), 240
Lovejoy, Owen, 89, 111–12, 132–3
Lower Omo Valley (Ethiopia), 152–3
Lower Paleolithic, 151
stone tools, 152, 169, 208
LSA see Later Stone Age (LSA)
Lucifer aldrovandii, 4
Lucy (hominin)
anatomy, 124
body proportions, 70, 72, 137, 142
discovery, 123
pelvis, 136
stature, 141
“Lucy’s child,” 141
body proportions, 142
Lufengpithecus spp
...
splitting paradigm,
140–1, 146–7
lunar cycles, 230
lunate sulcus, 219
Lundelius, Ernest, 243
Lyell, Sir Charles (1797–1875), 32
The Principles of Geology (1830), 5, 31
macaques, 60
McBrearty, Sally, 211–12
McGrew, William, 155
McHenry, Henry M
...
, 118–19
manuports, 153, 174
marine animals, 32
marmosets, 60
Marseilles (France), 230
Marshack, Alexander, 230, 233, 234
marsupials, 19, 25, 60, 63, 245
Martin, Lawrence, 95
Martin, Paul S
...
, 164, 166
hypotheses, 111
and prehistoric art, 232
and scavenging, 170
Mediterranean Sea, 168
Mellars, Paul, 234, 249
Meltzer, David, 241
Mendel, Gregor Johann (1822–84), 19
Meso-America, 247
Mesozoic era, 31
metabolic rate
and body size, 64
and brain size, 217
metabolism, cells, 200
Mexico, 250
Mezhirich (Ukraine), 249
Mezmaiskaya Cave (Caucasus), 186
mice, 100
microevolution, 19, 20
definition, 18
microliths, 151, 211
Micropithecus spp
...
J
...
out-of-Africa hypothesis, 187, 201–4,
213–14

Mungo, Lake (Australia), 244–5
muscles, 109, 110
Musée de l’Homme (France), 233
Musée des Antiquités Nationales (France),
233
musical instruments, 209
mutations, 50
see also genetic mutations
Na-Dene language, 241
Nairobi (Kenya), 105, 167
Namibia, hominoids, 107
Napier, John, 140
Nariokotome boy
age at death, 164
anatomy, 162, 163– 4
body proportions, 72
brain size, 161, 163–4
classification, 162
discovery, 56, 161
pelvis, 163
and speech, 163
spinal cord, 223
stature, 70, 160
teeth, 164
narrative, human evolution as, 7–11
Native Americans
genetic diversity, 242
genetic studies, 241–2
languages, 241
origins, 239
Natural History Museum (London), 13, 73,
95, 187
Natural History Museum (Paris), 4, 183
natural philosophy, 3–4
natural selection
and alleles, 20
conditions, 18
and convergent evolution, 19
Darwin’s views, 5, 24, 31, 34
mechanisms, 34
theories, 5, 18–19
Nature (journal), 121, 140, 141, 144
Nauwalabila (Australia), 244
Nazareth (Israel), 193
Ndutu, Lake (Tanzania), 197
Neander Valley (Germany), 182, 186
Neanderthal fossils, 3, 121, 210–11
Neanderthal phase of Man hypothesis, 183
Neanderthals, 164, 179–86, 192
anatomy, 179–81
art, 226
basicranial flexion, 223–4
behavior, 181–2
body size, 69, 70
body weight, 180
brain size, 180, 218
brow ridges, 194, 197
cannibalism, 182

Index
characteristics, 179– 80
classification, 183
cranium, 181, 193, 194, 195, 224
depictions, 184
discovery, 182–6
DNA, 186, 204
evolution, 5
fate of, 195–6
geographical distribution, 185, 211
and humans, 190
interpretation issues, 182– 6
and language, 180–1, 223– 4
lifestyle, 179
and Mousterian technology, 181, 193,
210
and multiregional evolution hypothesis,
193–6
origins, 13, 183, 204
skull shape, 180
speech, 180–1
stature, 180
teeth, 182
tools, 181
Neo-Darwinism, 18
Neolithic revolution, 151, 247
Neolithic transition, 248–52
causes, 250–1
characterization, 247– 8
and climate change, 250–1
interpretations, 248–50
and population expansion, 247, 250
see also agricultural revolution
neonates
brain size, 78, 218
larynx, 223
neoteny, in human evolution, 20
Nepal, 106
New Guinea, 243
New World see Americas
New World monkeys
classification, 60, 103
dentition, 62, 104
evolution, 24–5
fingernails, 47–8
New York University (USA), 232
Ngaloba (Tanzania), 197
Ngandong (Java), 190, 191
Niaux Cave (France), 233
niches, 19, 32, 34, 61, 63
Nilotic people, 69–70, 72
Noah’s ark model, 187
Noble, William, 225, 226
nomadism, 247
and hunter-gatherers, 248, 249
nomenclature, systematics, 45– 6
North America, 27
Eskimos, 69, 70, 72
mammals, 26
migrations, 239

plesiadapiforms, 65
pre-Clovis sites, 240–1
North American wolf, 19
Northwest Territories (Canada), 239
nuclear DNA, 200, 206
sequencing, 97
variations, 98, 204
nuclear family, 90
nuclear genome, 200, 204
nucleotides, 50, 51
in genome, 52
numerical taxonomy, 46
nutritional stress, and body size, 73
Oakley, Kenneth Page (1911–81), 226
ochre, 226, 230
red, 234
OH 9 fossil, 160, 162
OH 13 fossil, 145
OH 62 fossil, 141, 142, 143, 145
Old Crow (Canada), 240
Old World monkeys, 60, 90
brow ridges, 49
classification, 60, 103
dentition, 62
divergence, 97
evolution, 24–5
fingernails, 48
habitats, 131
species diversity, 103
Oldowan culture
stone tools, 153, 166–7
tool makers, 153, 154–5
Olduvai Gorge (Tanzania)
fossil bones, 57, 58, 171–4
Homo fossils, 144, 145, 162
discovery, 41, 122, 140, 141, 160
stone tools, 58, 153
olfactory sense, primates, 62, 63
Oligocene, anthropoids, 104
Olorgesailie (Kenya), 167
Olsen, Sandra, 58
Omo 1, brain case, 188, 189, 197
Omo 2, brain case, 188, 197
Omomyidae, 65
Omo River (Ethiopia), 57
Omo Valley (Ethiopia), 123
ontogeny, 150
opossums, 63
orangutans, 4, 12, 13
bipedalism, 109
classification, 49–50, 95, 100, 101
locomotion, 62
origins, 15, 104, 108
sexual dimorphism, 80–1
social organization, 80–1, 82, 83–4, 84, 90
testes, 90
toothwear patterns, 120, 137
orders, 45

271

Ordovician, mass extinctions, 32
Oreopithecus spp
...
(hominoids), 107
Ouranopithecus spp
...
multiregional evolution hypothesis,
187, 201–4, 213–14
see also single-origin hypothesis
out-of-Asia hypothesis, 162, 201–2
overkill hypothesis, 243
owls, 63
ox ribs, 234
Oxford University (UK), 217, 242
oxygen consumption, 114
oxygen isotopes, 27
Pääbo, Svante (1955– ), 226
Pacific, 239
Pagel, Mark, 217
painting
cognitive ability, 225
prehistoric, 229
wall, 248
see also cave paintings; pigments; rock
paintings
Pakistan, 106
palates, anatomy, 97
paleoanthropology
issues, 7, 12
and language, 10
narrative approaches, 7
paleoenvironments, hominins, 127
Paleolithic, 151
see also Lower Paleolithic; Middle
Paleolithic; Upper Paleolithic
paleomagnetic dating, 39, 40, 122, 161
Paleozoic era, 31
mass extinctions, 32
palm civets, 63
Pan spp
...
(hominins), 122
see also Australopithecus robustus (hominin)
paraphyletic groups, 48
Parapithecidae, 104
parapithecids, 104
Paris Basin (France), 31
Paris (France), 4, 183, 233
parsimony analysis, 53, 156
Pasolar (Turkey), 107
Patagonia (Argentina), 240
Patagonians, 71
Pauling, Linus Carl (1901–94), 96
peas, Mendel’s studies, 19
Peche de l’Azé (France), 234
Peche-Merle (France), 230
Pedra Furada (Brazil), 240, 243
Peking Medical College (China), 159
pelvic tilt, 110
pelvis, 132–3, 134, 136, 181
anatomy, 110, 112
pendants, 226, 230
Pennsylvania State University (USA), 105,
120, 173
Pennsylvania (USA), 240–1
percussion technique, 154–5
Perigord (France), 208
Permian, mass extinctions, 32
personal adornments, 212
Petralona cranium, 195
Petralona (Greece), 194
Phanerozoic era, 31
phenetics, 47
and cladistics compared, 46
phenotypes, definition, 19
phyla, 30
phyletic gradualism, 21
phylogenetic analysis, 53
phylogenetic contexts, 89–90
phylogenetic history, 81
phylogenetic indicators, 147–8
phylogenetic models, of hominin behavior,
87, 88–9
phylogenetic systematics see cladistics
phylogenetic trees, 15, 204
phylogeny, 3, 51, 52, 54, 107
australopithecines, 131
computer simulations, 53
hominins, 87, 126, 146–50
phytoliths, 120
Pickford, Martin, 105
picks, 166
pigments, 212
application, 230
dating methods, 39, 42
red ochre, 234
pigs
and faunal correlation, 39
toothwear patterns, 120

Pilbeam, David (1940– ), 15, 125–6
evolutionary theories, 100
lumping paradigm, 146
Pilgrim, G
...
, 15
Piltdown hoax, 13, 14, 16, 183, 184
pithecanthropines, 184
Pithecanthropus erectus (Java Man)
classification, 159–60
discovery, 159, 183
fossils, 121, 160
see also Homo erectus
Pittsburgh (Pennsylvania), 240–1
placental gestation, 21
placental mammals, 19, 25, 52, 61
plants
domestication, 247, 249, 250
in prehistoric art, 230, 233
plate tectonics, and evolution, 24–6, 104,
106
platyrrhines, 104
Platyrrhini, 103
see also New World monkeys
Pleistocene
climate change, 73, 180
glaciation, 250
hominins, 172–3
see also Early Pleistocene; Ice Age; Middle
Pleistocene; Late Pleistocene
Pleistocene/Holocene transition, 243
plesiadapiforms, 64–5
Pliocene, hominins, 172–3
polyandry, 81
polygyny, 73, 90
and body size, 84, 85
multimale, 81, 82, 84, 87, 90
unimale, 81, 82, 90
polyhedrons, 153, 154
polymorphisms, 51, 98–9
see also genetic variation
polyphyletic groups, 48
Pondaungia spp
...
, 103
Pope, Geoffrey, 168
population bottlenecks, 201
hypotheses, 204–6
population dynamics, 200, 204
population expansion, 162, 248
and agriculture, 247, 251
ancient, 204
hypothesis, 204–5
and Neolithic transition, 247, 250
population genetics, 19
population history, 204–6
population-pressure hypothesis, 250
porcupines, 58
Portugal, 230
postorbital constriction, 143

potassium
isotopes, 42
occurrence, 41
potassium/argon dating see radiopotassium
dating
pottery, dating methods, 39
Potts, Richard, 87–8, 170–1, 173, 174
Potwar Plateau (Pakistan), 106
pre-Clovis culture, 240
sites, 240–1, 243
precocial strategy, 78, 218
predation, 32, 56
and group living, 81
visual predation hypothesis, 63
predator-avoidance behavior, 111
predator–prey relationships, 78
predators, 56, 84, 224, 239
in prehistoric art, 230
vision, 63
prehistoric art, 229–35
age vs
...
Douglas, 250, 251
primate adaptation, origins, 63– 4
primate evolution, 64–6
primate models, of hominin behavior,
87–8
primates, 34
adaptive radiations, 13, 64–5
alliances, 220, 221
body size, 60, 64
brain size, 60, 63, 217–18
classification, 60, 65
cognitive ability, 221
common ancestors, 99–100
competition, 78
definition, 61–3
dentition, 62
diet, 64, 80, 81, 114
family tree, 61
fingernails, 47–8, 50, 62
fossils, 64
geographical distribution, 61
higher, 103
and human evolution, 60–6
as large mammals, 75–8
locomotion, 62
longevity, 63
olfactory sense, 62, 63
origins, 64–6

Index
quadrupedalism, 62, 110
social behavior, 87–9, 220–1
social interactions, 83– 4, 220, 221
social organization, 61, 80– 6, 220
sociobiology, 60
sounds, 224
specializations, 60
teeth, 65
vision, 62, 63
vocalization, 181, 224
Primates (order), 60
reproductive output, 75
social organization, 80
primatology, field of study, 60
primitive characters, 47– 8
Princeton University (USA), 75
Proconsul spp
...
(propliopithecids), 104
Propp, Vladimir (1895–1970), 7
Morphology of the Folk Tale (1928), 7– 8
prosimians, 34, 60, 65, 104
brain size, 63, 104
dentition, 62
fingernails, 47–8
jaws, 116
proteins
amino acid sequencing, 97
electrical properties, 50
electrophoresis, 97
enzymatic digests, 96
immunological reactions, 50
sequences, 53
see also blood proteins
protein, sources of, 64
provenance, fossils, 160
psychological theories, 225
Psychozoa, 6
Ptolemy (c
...
P
...
(parapithecids), 104

quadrupedalism, 96, 104, 111
energetics, 114
primates, 62, 110
vs
...
females, 83
reproductive rate, 75
reproductive strategies, 169
reproductive success, 83
reptiles, 9, 32, 64
brain size, 217
restriction enzymes, mapping, 97
rhinoceroses, 230
Rhodesian Man, 196–7
ribosomal DNA, mutation rates, 52
Richard, Alison, 64
Rimbach, K
...
, 196
rituals, 210
mortuary, 182
and prehistoric art, 232–3
skulls in, 234
Robinson, John, 136

273

robust australopithecines, 122, 123, 124,
137–8
anatomy, 135–7
diet, 90, 137
habitats, 137
hands, 138
phylogeny, 148, 149, 150
see also Australopithecus aethiopicus
(hominin); Australopithecus boisei
(hominin); Australopithecus robustus
(hominin)
robusticity
reduction, 71–3
and technological advancement, 73
skeletal, 71, 137–8, 188
rock paintings, 212
dating methods, 42
see also cave paintings
Rockies (USA), 239
rodents, 60
Rodman, Peter, 112–13, 114
Roehampton Institute (London), 223
Rogers, Alan, 204, 206
Rogers, Jeffrey, 98–9
Ross, Caroline, 78
r-selection, 75, 76, 78
Ruff, Christopher, 69–70
Rusinga Island (Kenya), 106
Russia, 249
Rutgers University (USA), 114, 174
Ruvolo, Maryellen, 99, 203
sagittal crest, 136, 147
Sahara, 27, 192
Sahelanthropus tchadensis (hominin), 100
bipedalism, 126
characteristics, 126
discovery, 124, 127
habitats, 127
taxonomic issues, 126
Sahul landmass, 244
St Acheul (France), 166
Saint-Césaire (France), 181, 210–11
Salé (Morocco), 160, 197
salmon, 233
sample bias, 147–8
San (Bushmen) art, 232–3
Sangiran dome (Java), 160, 161
Sarich, Vincent M
...
hunting, 111, 170–5
Schaaffhausen, Hermann, 182, 186
Schmid, Peter, 135, 137
Schöningen (Germany), 175

274

Index

Schrenk, Friedemann, 143
Schultz, Adolph, 14
Schwalbe, Gustav, 183, 184, 186
Science (journal), 64
Scottsbluff culture, 242
scrapers, 153, 154, 166, 209
sculpting, 210
sea-level changes, 32
seals, 233
sedentism, 247, 248, 250, 251
seed-eating hypothesis, 111
Senut, Brigitte, 133
Serapia spp
...
(1930– ), 15, 104, 119
lumping paradigm, 146
Simpson, George Gaylord (1902– 84), 100
Sinanthropus pekinensis (hominin), 159– 60
single-crystal laser fusion, 41, 161
single-origin hypothesis, 159, 187, 189,
192
concept, 205
and mitochondrial Eve hypothesis, 200
support, 193, 197, 198, 203, 204
see also out-of-Africa hypothesis; weak
Garden of Eden hypothesis
single-species hypothesis, 15–16, 146,
184–6
Sivapithecus spp
...
female, 83
primates, 87–9, 220–1
social carnivores, as hominid models, 88
social cognition, 221
social complexity, and agriculture, 250, 251
social evolution, models, 90
social groups
hominoids, 90
primates, 80, 81, 83
social interactions
and language, 226–7
primates, 83–4, 220, 221
social organization
ancestral, 89
apes, 80–1, 89–90
and brain expansion, 220
consequences, 83–4
definition, 80
determinants, 81–3, 89
ecological effects, 80
fission–fusion, 90
hominins, 87
hominoids, 82
humans, 90
hunter-gatherers, 225
primates, 61, 80–6, 220
and sexual dimorphism, 80, 81, 84, 90
theories, 83
sociobiology, primates, 60
Soffer, Olga, 249
Solo Man, 190
Solutrean blades, 210
sound perception, 222
sounds, primates, 224
South Africa, 143
australopithecines, 121–2, 137, 156
brain cases, 188
caves, 44, 57, 212, 226
hominin fossils, 15, 219
Homo spp
...
, 194–5
Neanderthals, 195
prehistoric art, 229, 233
stone tools, 168
spears, 72–3, 230, 232
wooden, 175
spear throwers, 230
specializations, primates, 60
speciation
and adaptation, 6, 22
and climate change, 24, 27
determinants, 22, 24
events, 159
sympatric, 21, 24
use of term, 21
see also allopatric speciation; cladogenesis
species
definitions, 45–6
evolution, 30
longevity, 34
species diversity
apes, 106
catarrhines, 103
cercopithecoids, 105
determinants, 21
dinosaurs, 34
hominins, 146–7
hominoids, 103, 105
and mass extinctions, 30, 33–4
species hybridization, 188
species trees, 51, 98, 99
speech, 163
anatomical evidence, 181
evolution, 222–3
genetic evidence, 226
production, 223
see also language
spheroids, 166
spider monkeys, 60
spinal cord, 223, 224
splitting paradigm, vs
...
, 184

striae of Retzius, 119
striding gait, 109, 133, 134
Stringer, Christopher, 73, 145, 187, 196
strontium–calcium ratios, 137
Strum, Shirley, 87
Stw 53 fossil, 141
sub-Saharan Africa
archeological time periods, 151–2
catarrhines, 103
human fossils, 189
subsistence, 72, 166, 239
hypotheses, 171–3
strategies, 73, 175
Sunda Land, 243
SUNY see State University of New York
(SUNY)
survival of the fittest
use of term, 18
see also natural selection
Susman, Randall L
...
, 63–4
Swanscombe (UK), 168, 194
Swartkrans (South Africa), 122, 123, 135,
137, 138, 156, 160
sweating, 70
swing phase, 109–10
Swisher, Carl, 161
symbolic expression, 233, 234, 248
symbolic objects, 212
sympatric speciation, 21, 24
symplesiomorphies, 48
synapomorphies, 48, 49
syntax, 224
Syria, 248, 249, 250
systematics, 45–55
definition, 45
evolutionary, 46
morphological approaches, 95–6
nomenclature, 45–6
philosophies, 46–7
see also cladistics; classification systems;
molecular systematics; phenetics
Tabun cave (Israel), 192, 193
¯
Tagua-Tagua (Chile), 240
Taieb, Maurice, 123
tails, 60
Taima-Taima (Venezuela), 240
Tanzania
hominin fossils, 127
human fossils, 197
stone tools, 153
taphonomy, 56–7
studies, 58
Tardieu, Christine, 133
tarsiers, 13, 60, 65
locomotion, 62
tarsioid hypothesis, 13
Tasmania, 240, 243

275

Tasmanian wolf, 19
Tasmanians, 5
Tata (Hungary), 234
Tattersall, Ian, 6, 10, 146–7
Taung child, 118–19, 121–2
Taung (South Africa), 121
Tautavel (France), 194
taxa, definition, 45
technological advancement
and hunting, 72–3
phases, 225
and robusticity reduction, 73
technologies, new, 166–9
teeth
anatomy, 97, 116–17
apes, 87, 100
carnivores, 230
carved, 234
characteristics, 119
dating methods, 39
development, 164
elephant, 226
eruption patterns, 118–19, 164
evolution, 116–20, 147
hominins, 57, 100, 124–5
Homo erectus, 90, 164, 190
homology, 47
Neanderthals, 182
primates, 65
reduction, 72, 73
as tools, 182
traits, 147, 148, 150
wear patterns, 111, 120, 137
Homo spp
...
, 118, 141–2, 143, 144, 145,
161
stone tools, 152
Turkanapithecus spp
...
S
...
, 27
Vulpes spp
...
W
...
, 123, 171–2, 174
discovery, 41
Zinjanthropus boisei see Australopithecus boisei
(hominin)
Zoukoutien (China), 159–60, 191
Upper Cave, 191, 192
Zuckerkandl, Emile, 96



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