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How Do We Study Human Evolution?
Disciplines
Anthropology and Biology, but they have many subdisciplines
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It incorporates both biological and
cultural sciences and other relevant disciplines
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 Physical Anthropology is the study of human biology within the framework of evolution
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It concerns genetics, evolutionary biology, nutrition, physiological adaptation
and growth and development
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 Anthropometry is the study of craniology and comparative anatomy
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Between
individuals, populations and species
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-Archaeology is a body of methods designed to understand the human past through the examination
and study of its material remains
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-Biology concerns itself with evolution, natural selection and Mendelian genetics
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His treatise on chronology used
combination of Middle Eastern and Mediterranean histories and Holy Scriptures to ‘date the world’
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With contacts like Matthew
Boulton, Josiah Wedgewood and James Watt he set up the Lunar Society which because the main
intellectual powerhouse of the Industrial Revolution in England
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He expounded this in Zoomania
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Lamarck
An eminent French biologist
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Lamarck proposed the law of the ‘inheritance of acquired characteristics’
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-Questions- Why do mice retain their tails even if they are cut of at birth for many generations? Why
do blacksmiths sons not develop strong arm muscles if they become clerks?
Charles Lyell
The foremost geologist of his day
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He was one of the first to believe that the
world is older than 300 million years, on the basis of its geological abnormalities
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He was responsible for renaming the geological eras now known as the Palaeozoic, Mesozoic and
Cenozioc
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He developed the theory of
natural selection on his trip on the Beagle
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He decided to build up a reputation by becoming an expert
on one group of animals- during which time he drew on his international network of friends round the
world
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Alfred Russell Wallace
Biologist and a social reformer, known for his co-discovery of natural selection and his work on
biogeography
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Wallace began
investigating spiritualism in the summer of 1865
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He eventually said that
something in ‘the unseen universe of Spirit’ had interceded at least three times in history:
-The creation of life from inorganic matter
-The second was the introduction of consciousness in the higher animals
-The third was the generation of the higher mental faculties of mankind
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The idea that evolution
has some purpose and direction is still current among some religious groups who now talk about
intelligent design as a driving process
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The small genetic difference, however, still
results in enormous differences in species
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Molecular
evidence suggests that the linage that led to modern humans split from the chimp lineage around
10mya
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5-2
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Raymond Dart discovered Australopithecus afarensis
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It was only an immature skull that was found
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Some fossils were found that were more robust and were called Paranthropus robustus
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Zinjanthropus boisei (2
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It inhabited the dry savannah grasslands of eastern Africa,
and had a skull highly specialised for heavy chewing
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Australopithecus afarensis (3
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8 mya)
Don Johansen made this discovery in the Awash River valley near Hadar
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Johaneson named this A
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Lucy was a small adult female,
about 1
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Australopithecus anamensis (39-4
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Australopithecus bahrelhazali (3
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5 mya)
Found by Michael Brunet in Chad
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anamensis or not
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It was significant however as it is the furthest west a fossil hominid has been found
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4 mya)
Tim White found this in Ethiopia
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The specimens include
a partial female skeleton from an individual weighing 50kg and standing 1
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It is much more
primitive that Lucy
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5 mya)
Tim White also discovered this
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Some dental features are quite humanlike but most remarkable was that this may have been the first hominid to use stone tools
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IT may have been the link between A
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Homo habilis (1
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6 mya)
Louis Leakey and his team found this in the Olduvai Gorge
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It is believed
that this was the creator of the Oldowan tools
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Homo rudolfensis (2
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6 mya)
A hominin species discovered in 1972 by Lake Turkana, found by a member of the Leakey team
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habilis and it is difficult to tell the two apart
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6 mya)
The first finding was in the 19-20th century, and at the time were not recognised as early hominins
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The boy would have stood 160cm tall and would have grown past 1
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Brain capacity was 880cc and his stature was well adapted to open, tropical environments
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6 mya)
An advance in stone tool technology is identified with this species
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Kenyanthropus platyops (3,5 mya)
Meave Leakey found what was assumed to be a completely new genus and species of early human
ancestor
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8-6
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Sahelanthropus tchadensis (7 mya)
In 2001, Michael Brunet discovered a mostly complete cranium with a small brain- 320-380cc
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It also has
features considered to be more advanced, like small canines and thick tooth enamel
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Due to its
age, it puts it close to the human-chimp split
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Bones and teeth from around 12 individuals have been
dated to between 95,000 to 17,000 ya
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Origin and how they got to Flores is a mystery
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The skull was found the following year
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Dentition appears similar to most early Homo
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Evolution of Bipedalism
Origin of Bipedalism
Originally primates were arboreal
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Trees
provide food and safety from many predators
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This is difficult to pinpoint due to a 7-4 MY gap in the fossil record
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Most of these are associated with the skeletal system
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-Thigh bone slopes inward from the hip to the knee- places the feet under the centre of gravity
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-Well developed muscles are on the side of the hips- prevent the bod falling to one side when all the
weight is on one foot mid-stride
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-Enlarged joint surfaces
-Adducted knees- can straighten knee joint to extend he leg (chimps can’t)
-Lower/upper spine curvature (S-Shape) - places centre of gravity over legs and feet
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-Feet more flattened (except the tarsometatarsal arch)- specialised as a weight-bearing platform with
an arch that acts as a shock absorber
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Partially terrestrial primates are at
an advantage when trees are widely spaced so terrestrial species may have been advantaged by drier
conditions
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Only humans, however, have
habitual erect bipedal locomotion that frees the forelimbs from an obligatory function of support and
locomotion
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Evidence of bipedalism is thus the feature looked for in fossil records
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It is possible that bipedalism is not entirely unique to the hominids, and bipedalism may
have evolved more than once within the hominins
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tchadensis’s foramen magnum suggests an upright skull, but no bones below the skull have been
found
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tungenensis discovered in central Kenya had a femur head angle and femur neck length
suggesting bipedalism and a humerus and phalanges suggesting arboreal activity
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Both of the above are considerably closer to the supposed divergence of humans
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afarensis probably stood erect based on its skeleton and the footprints found at Laetoli (see slide
24)
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‘Lucy’s’ skeletal features suggest a slightly
clumsy biped that may still have spent some time in the trees
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-A
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It lacks the features making it well adapted for living in trees, but it suggests it is more likely to have
moved by Palmigrade Clambering
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Its four toes were
modified for upright walking, but unlike later hominids it still has an opposable big toe
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There appears to be two main transitions between the early human ancestor and human bipedalism
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-Further modification produced a pelvis and lower limb that were more effective for upright walking
and running but that were no longer useful for climbing
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This allows the conclusion that bipedalism predates encephalisation
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Recent evidence suggests that early hominids may well have still climbed trees- possibly for
protection at night and to escape from day-time predators
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In early 2009, the discovery of new footprints from Ileret in northern
Kenya was announced, dated at 1
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The prints reflect
height, weight and the walking style of modern humans
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The footprints suggest that H
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The greater mobility and the
consequent adaptation to a wider range of environments might be what enabled them to become the
first hominin to leave Africa
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However stone use did not
appear until after bipedalism
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-Food gathering- 80% of bipedal behaviour in chimps is related to stationary feeding, only 4% of
direct locomotion
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Bipedal locomotion is more efficient at low speeds than quadrupedal
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Also hair loss
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Evolution of the Hominid Skull and Brain
Skull Anatomy
The cranium is that part of the skull that holds and protects the brain, also called the cranial vault
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Other features
include processes, which are areas where the bones have extra material for attachment of muscles and
ligaments, foramina, which are holes in the bones through which nerves and blood vessels pass, and
sinuses, empty spaces in the bones that make the skull lighter
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Much of the visible appearance consequently depends
on the shape and qualities of these bones
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Forensic
pathologists and biologists can reconstruct the superficial appearance of a face from the human skull
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Overall the skill has become taller, with fewer muscle attachment ridges, a reduced zygomatic arch,
shorter jaws and face, a more vertical forehead to accommodate the development of the forebrain and
a decreased need for powerful neck muscles
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As hominins evolved, brain size
increased dramatically
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Over a period of around 3
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A
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The change in brain size from
Australopithecus to H
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erectus is substantial and cannot be accounted for simply
in terms of increased body size
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erectus around 1
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When corrected for body size, intelligence correlates very roughly with brain size
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-Regions
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This can be seen using endocasts
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Although there is some suggestion that the brain organisation of
Australopithecus afarensis was essentially human-like, this has been challenged
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The issue of whether reorganisation of the brain had occurred by the time of A
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Endocasts of H
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They may
have had some form of communication based on vocal articulations
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If brain re-organisation towards human proportions
only became with Homo, it would fit with other changes
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-The development and use of stone tools paralleled the increase in brain size
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A recent study found that action planning for tool-making and language use the same brain
structures and suggest that the two co-evolved
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75 mya with the start of Acheulean tool technology
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It has been suggested that increased social complexity in early hominins
required greater cognitive processes
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There is some support in that
primates with more complex social structures have a larger neocortex, the thinking part of the brain
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-Improved Diet
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Some researchers suggest the transition from a predominantly vegetarian diet to
hunting and meat-eating allowed for brain expansion
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Cooked
tubers may have provided the energy that drove the evolution of larger brains
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The idea is contentious
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8 million years ago
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Consequences of Brain Increase
Irrespective of what drove or facilitated the increase in brain size in Homo, there were several
consequences, such as the evolution of larger heads to accommodate the larger brains
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This requires an increase in
maternal care while the offspring is incapable of caring for itself, and an extended period of
dependency for infants to learn new skills
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This is different from
chimpanzees with their promiscuous mating system and mothers having sole responsibility for infants
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This required remodelling of the vascular system of the brain
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Shown by the increase in the size of the foramina as brain size increased from A
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sapiens
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With the evolution of Homo, brain
power and tools began to replace brute strength and food demands shifted from vegetarian to meat
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Evolution of the Human Hand
The Primate Hand
There are 27 bones in the wrist and hand
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The
carpels join with the two forearm bones, the radius and ulna, forming the wrist joint
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There are five metacarpals forming the palm of the hand
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One metacarpal connects each finger and thumb
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The metacarpals and
phalanges are joined at the metacarpophalangeal joint
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The one closest to the knuckle is the proximal IP joint
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Primate Use of Hands
Primates are hand-to-mouth feeders
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They move
around in trees by traversing the branches using a variety of forms of locomotion that use their hands,
climbing or brachiation while hanging from a branch
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The hand
of monkeys and apes take several forms but the four fingers have essentially the same form and
functional capacity
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Finger movements are possible and allow scratching, digging and picking up small objects by
pinching between the thumb and the index finger
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The greatest variability is in the thumb, which tends to be short compared to the fingers
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Gorilla thumbs most closely resembles the human thumb,
yet gorillas have never been observed to use tools
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Although there are some
features which allow some precision grip in chimps, the chimp hand is not particularly well adapted
for manipulation
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This is
probably because the hands of chimps are required for multiple functions, and are therefore subject to
strongly conflicting selection pressures
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In particular, the manipulative capabilities of the apes seemed to be limited to the distance
between the fingertips and the tips of their relatively short, weak thumbs
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The Human Hand
Of major significance, humans have a long thumb relative to the other fingers
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This is the basis for
human thumb and fingertip precision grip capability
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Humans have a proportionately large flexor pollicis longus muscle
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It allows the thumb pad to be oriented towards the fingers, and the
thumb to be braced against by the fingers
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Humans have relatively large pads on the tips of the thumb and fingers as well, which are supported
by broader tufts on the distal phalanges
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In humans, the head of the third metacarpal naturally orientates towards the thumb when the hand is
closed, assisting in grasping large objects
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In general, the modern Homo sapien hand
shows an enlarged, opposable thumb which is good for manipulating objects and creating a powerful
grip
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What of the Early Hominins?
Early hominins were quite small
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One interpretation for
the forelimb strength of the early hominins is that they were effective climbers- they did not, however,

have grasping feet
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He legs provided support and upward propulsion but no grip
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There is very
little hand material
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They have a much shorter thumb that departs the hand much closer to the wrist
and the fingers are similar to living humans in their relative size
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afarensis had manual proportions that were at least partially human and would have allowed a
human-like precision grip capability
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These changes mean the thumb, index and middle fingers can form a
three-jaw chuck, allowing the hand to conform to, and firmly grasp and manipulate, a wide range of
irregular shapes
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Rocks could have been used as primitive tools, as the wrist structure can
absorb the shock of repeated hard strikes more effectively than the ape hands
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Also, neither apes nor Lucy could flex the fingers on the ulnar side of the hand- far side- towards the
base of the thumb
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Additional changes to the wrist, etc
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afarensis
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The opposition of the fourth and fifth fingers combined
with ulnar deviation of the wrist and hand and are unique to modern humans
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This was not possible for apes and early hominins who
could only hold a stick at a slight angle to the vertical and not wield it like a club
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Other Early Hominins
Australopithecus robustus was claimed to show clear evidence of human-like manual dexterity
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It
was a species that evolved from A
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The thumb
resembles a human thumb and indentations revealed attachment points for the flexor pollicis longus
muscle
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There is, however, some questions
as to whether the hand was from robustus or habilis
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The finger
bones, however, are curved like those of the A
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What Drove the Evolution of the Hand?
One suggestion is that human-like proportions of the hand and the enhanced thumb/hand relationship,
evolved as an adaptation to stone tool-making, proved by the humans hand well-adapted to tool
making
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afarensis effectively had human-like hand proportions and yet predates
the appearance of stone tools in the archaeological record, many regard this as sufficient evidence that
human-like hand proportions are not a specific adaptation to making tools
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In
particular, the distal finger bones lack the large fingertip surfaces that are found in living and fossil
humans
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Hand anatomy may be an adaptation to ancestral practices in ancestral environments, which happened
to provide a fortuitous preadaptation which humans then exploited for tool usage
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However, tool use in these has been contested due to cut marks found on bones
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We know that sometime after Lucy, a more mobile joint developed at the base of the small finger, the
origin of which is unknown
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erectus
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The

nature and timing of the evolutionary transition from ape-like t human—like hand proportions,
however, remains unclear because of a lack of appropriate fossil material
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It has some Australopithecine features like a strong flexor apparatus, associated with arboreal
locomotion, but with some human like features, like a long thumb and short fingers, associated with a
precision grip and possibly stone tool production
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98 mya, even if it did not
actually make them
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Kivell et al
suggests that A
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Without tools, early hominins would have relied on the
versatility and strength of their hands to collect food and on their teeth and jaw alone to process this
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There is little doubt that the evolution of the modern hand
was a major step towards the development of tool use and human culture
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Lower Palaeolithic
This is a unit of archaeological time that begins around 2
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It begins with the oldest identifiable stone tools
around 2
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Two major stone tool industries: Olduwan- the oldest
identified tools, and the Acheulian, beginning around 1
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-Olduvai is located on the eastern branch of the Great Rift Valley, which stretches for 4,000 miles
down the east side of Africa
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Four Significant Results of Geological Rifting at Olduvai
-Faulting, or earth movement, exposes geological strata that are normally hidden deep in the earth
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-Strata formed by rapid sedimentation and the hominin fossils and archaeological sites preserved
within them, can be dated by relative methods
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Earliest Evidence for Tool Use: the Olduwan
The Olduvai Gorge, in the lower Palaeolithic, had produced the richest evidence of lower Palaeolithic
activity
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Lower Palaeolithic Olduwan Tool Industry
First identified in the earliest Hominin site- around 1
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They consist of relatively simple pebble
tools, initially described as chopper chopping tools, dominated by big cobbles
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Olduwan
Olduwan is the oldest recognised hominin tools
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The tools were made by hard hammer percussion, and consisted of core forms, fakes and hammer
stones
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Binford argued for
hominins as scavengers
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Hominins hunt, scavenge, or collect food and raw materials from the general locality where they
habitually live and bring these materials back to some central or home-base site to be shared with
other members of their co-residing group
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It began as early as 1
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Characteristics
More control over techniques, sophisticated understanding of geometry, working towards preimagined types, and it was part of the process that allowed the adaptation to move out of Africa, and
allowed them to be a more efficient scavengers
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erectus discovered in the 20’s and 30’s, as well as recent excavations at this
site are the largest collection of H
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The hominin remains belong to approximately 40 adults
and children
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Interpretations

H
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Homo erectus was able to emigrate from Africa owing to more advanced culture and a more modern
anatomy as compared to earlier African predecessors
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Homo erectus Dispersal
Grade
An evolutionary grouping of organisms sharing a similar adaptive pattern
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Clade
A group of organisms sharing a common ancestor
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Homo erectus
Morphology
-Body Size- Anthropologists estimate that some Homo erectus adults weighed well over 100 pounds,
with an average adult height of about 5 ft
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The increased height and weight H
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-Brain Size- Early Homo had cranial capacities ranging from as small as 500cm3 to as large as
800cm3
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erectus has a cranial capacity of 750 t0 1250cm3
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erectus and
Homo sapiens is about the same
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The
braincase is long and low, receding from the large brow ridges with little forehead development
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-Nuchal torus- a projection of bone in the back of the cranium where neck muscles attach: used to
hold up the head
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4

Olduvai
(Tanzania)

Large individual, very robust (male?) H
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6

Nariokotome
(Kenya)

Nearly complete skeleton; young male

1
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Turkana
(Kenya)

Oldest well-dated H
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erectus from Africa and Asia, but are quite different from earlier
hominins
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These discoveries suggest the possibility that the
first hominins to leave Africa were a very early form of H
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Homo erectus from Indonesia
Six sites in eastern Java have yielded all the H
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The
oldest Java fossils are close to 1
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A very late survival in Java, where the most
recent H
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Dates

Site

Evolutionary Sigificance

50,00025,000

Nggandong (Java)

Very late survivor of H
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67,000410,000

Zhoukoudian

Large sample: most famous H
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6mya

Sangiran (Java)

First discovery of H
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6mya
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8mya until 10,000ya
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Zhoukoudian Homo erectus
The fossil remains of H
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erectus anywhere
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More than 100,000 artifacts have been recovered from the site
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erectus Comparison
Homo erectus remains from East Africa show several differences from the Javanese and Chinese
fossils
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Some researchers call for a separate species status for the
African material to distinguish it from the Asian fossil material
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erectus be used for
solely Asian material
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9 –
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erectus morphology from any site in
Europe
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85 –
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erectus
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75

Dmanisi (Georgia)

Oldest well-dated hominins outside of
Africa; not like full H
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Acheulian
A lower Paleolithic stone tool industry that includes bifacially worked hand axes and cleavers and
many kinds of flake tools
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4mya in Africa, spread across many parts of the
temperate to tropical parts of Europe and Asia, and ended roughly 200,000ya
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Interpretations of H
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erectus is the first hominin for which we have definite evidence of wide geographical dispersion
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The Dmanisi hominins and a new discovery
from Bouri, Ethiopia, call into question the validity of an erectus/ ergaster distinction
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Techniques
-Stratigraphy- study of the sequential layering of deposits
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-Cross-dating- estimates the age of artifacts and features based on their similarities with comparable
materials from an archaeological context of known age
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-Fluorine analysis- estimates the relative age of bones from a site based on fluorine content
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Stratum: A single
layer of soil or rock
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For example, extinct marine arthropods called trilobites can be used as an index fossil of
Cambrian and Ordovician geological formations
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Half Life
The period in which one half of the amount of a radioactive isotope is chemically converted into a
daughter product
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25 billion years, half the potassium-40 remains: after 2
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Chronometric Dating
Most techniques are radiometric, as the steady decay of radioactive isotopes provides estimates in
actual number of years
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-Argon-argon- uses the ratio of argon-40 to argon-38 for dating igneous and metamorphic rock
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-Palaeomagnetism- technique based on the constantly shifting nature of the Earth’s magnetic pole
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-Thermoluminescence- measures the accumulated radiation dose since the last heating or sunlight
exposure of an object
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-Uranium series dating- radioactive decay of short-lived uranium isotopes
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Pleistocene Epoch
Middle- 780,000-125,000
Late- 125,000-10,000

Palaeolithic
Upper
Cultural period beginning roughly 30,000-40,000 and ending about 10,000ya
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It is best known from Western Europe, similar industries are also known from
central and Eastern Europe and Africa
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Glaciations are
associated with colder temperatures in northern latitudes and more arid conditions closer to the
equator, most notably in Africa
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Homo heidelbergensis
Dispersed over three continents
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erectus and H
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Considered by many researchers to be a transitional species between erectus and
sapiens
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Middle
The cultural period that began about 200,000ya and ended around 30,000-40,000 years ago
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Culture
Mousterian is the best known Middle Palaeolithic tool industry
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sapiens
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Technology
The composite tool was one of the most significant middle palaeolithic innovations
...
Also developed the discoid prepared-core technique
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For example, a prehistoric knife typically included a handle
or shaft, a chipped stone blade, and binding materials such as glue or sinew to hold the blade firmly
in place
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Discoid Technology
A prepared-core technique in which flakes are struck toward the centre of the stone core
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It is also called the radial core method
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Subsistence
Neanderthals and other Middle Palaeolithic pre-modern humans were successful hunters
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Symbolic Behaviour
The prevailing consensus is that Neanderthals were capable of articulate speech
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sapiens had some significant behavioural advantages over
Neanderthals and other pre-modern humans
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Lower to Middle Palaeolithic
Acheulian technology changed relatively little until near the end of the Lower Palaeolithic
...
There is possible evidence of temporary shelters and hearths
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Prepared-core method for striking flakes from stone cores was invented
around 300,000ya
...
This enables predictable flake shapes and thickness, and can be efficient in the use of raw
materials
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Neanderthals

Many anthropologists classify Neanderthals as H
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Neanderthal fossil remains have been found at dates approaching 130,000ya
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Flexed
The position of the body in a bent orientation, with arms and legs drawn up to the chest
...

Chatelperronian
Pertaining to an Upper Palaeolithic industry found in France and Spain, containing blade tools and
associated with Neanderthals

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