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Hominins
This is the Hominid sub group made up of human and their human like ancestors
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Several other hominin forms are now
extinct such as Homo Habilis and Australopithecus
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This means they they
are not only capable of walking on two legs, but that it is their habit to do so
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The features of Hominins ultimately relate to their bipedal lifestyle
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Describe trends of biological evolution with respect to skeletal changes linked to
bipedalism
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Humans have taken this to the extreme and walk on two
legs all of the time
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It is
thought that being bipedal allowed humans to exploit the ground niches, which probably
offered more variety of food at a time when forests were shrinking
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This change to bipedalism was
probably the most important step in our evolution because it freed the hands, allowing us to
take advantage of our larger brain
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● The human pelvis is relatively short and strong in a bowl shape in order to carry the
weight of an upright body whereas Apes have a longer narrower pelvis
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This brings the knees and feet nearer the midline, which enables more efficient two
legged walking compared to chimpanzees
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In apes the knees bend outwards under the hips as their
femur angled into the knee so when they lift one foot off the ground they lose
balance
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This produces a swaying
movement as they walk
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This is so that the eyes can face forwards when standing
upright
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Their feet are
also flat
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● Human​ hands​ are much smaller than a chimpanzee’s, the thumb is relatively long
and more mobile
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A
chimpanzee's hand is not suited to a precision grip but human hands can have both a
power grip and a precision grip
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Like all primates both can grip
objects with a ​power grip​, but only humans can also use a ​precision grip​
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Apes had a ​flatter brain case​ (smaller brain) which allows for greater muscle attachment
sites needed for aggressive facial displays
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It is very likely that large
teeth and large jaws are associated with diets high in fibrous plant food
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These stresses are resisted by the ​brow ridges above the eye sockets and
the ‘siminian shelf’​ that strengthens the inside of the lower jaw
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● Canine teeth ​in males and females are the same size in humans but in apes they are
much larger in males
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​ Not the case in humans
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● Hair loss helped as our ancestors lived in tropical Africa and lived and worked
outside, so it helped to evaporate sweat and keep cool by having thin hair
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● Apes had a shorter ​Pharynx tract​ this was one of the reasons they cannot have
spoken language
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● Increase in brain size is mainly due to the increase in
size of the ​cerebrum​
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● Wernicke’s area ​is a sensory region concerning the
interpretation of sound
● Broca’s area ​is a motor region, responsible for the interpretation of sound into
meaningful sequences
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● Cranial capacity changed from about 400cc to 1500cc
Apes have a much smaller brain size 450cm​3 ​vs 1400cm​3
Chimpanzee’s have a brain size of 400cm​3

Apes (quadrupedal)

H
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Pelvis is long and narrow

Pelvis short and
wide

Supports organs above​, also must allow
for bigger head during birth
Changed ​shape of the hominin pelvis
beneficial in locomotion:
Changes ​position of muscle attachmen​t
more efficient locomotion;
Carrying angle​ – more efficient
locomotion because movement
notside to side (or implied) /
balance /stability when walking
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Position of the occipital condyles (the part of
the skull that articulates with the vertebral
column)

They have moved from the back of the skull to the
middle of the skull to keep to keep the head above
the centre of gravity

Rib cage

Flattened ​from front to back ​which moves the
centre of gravity closer to the spine
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Spine shape

Changed from ‘C’ shape to ‘S’ shaped
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This improves both balance and
it absorbs the shock of walking
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This results in:(a)​ ​Improved balance
(b)​ ​The support of the upper body
(c)​ ​Enlarges the valgus angle
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Femur length and shape

Femur is stronger, ​longer​ and angled inwards from
the hip so that the knees nearly touch (increased
valgus angle)
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Overall the legs are longer than the arms in humans
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Shape of the foot

The foot has changed in two main ways:(a)​ ​The foot has changed to become a platform
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The foot has lost all grasping
ability
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This provides
a shock absorber effect and a spring that
facilitates long distance travelling
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You should be able to see that the
top of the femur increases in size, which reflects the increased weight load on the joint as
humans spent more time walking on two legs and grew larger in size
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In humans however, the thumb is enlarged
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Humans are the only ape which can achieve the full thumb tip to
finger tip ​precision grip​
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Lastly, the
bones of the fingertip have an enlarged apical tuft, which increase the surface of the finger
tip for grasping fine objects
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sapiens

Reason for change

Smaller cranial
capacity (~450cc)

Bigger cranium
(~1450cc)

Increased brain development

Sagittal crest
Large zygomatic
arch
Large jaw
Teeth bigger
Brow ridge

No Sagittal crest
Small zygomatic arch
Small jaw
Teeth smaller
No brow ridge

More refined diet, no need for really
strong chewing muscles, muscle
attachment points, or teeth

Nuchal crest

No Nuchal crest

Head vertical on spine – less
muscle attachment needed
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Oldowan ​first used by ​Homo habilis
● Very simple tools with a few flakes removed
● Used to chop and scrap
● Found with the fossils
● Used to break open bones or take out meat
Acheulian ​first used by ​Homo erectus and Archaic Homo sapiens
● Bi-faced, teardrop shaped which had been carefully
crafted to a standard design
● Much more crafted than oldowan as more chips
remove
● Tools took much longer to craft with on average 65
blows per tool
● Used as hand-axes and cleavers
● Made for specific jobs e
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basic design altered to make
scrapers etc
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g
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Upper Paleolithic ​first used by ​Homo sapiens and Neanderthals
Tool making techniques were further refined
● Most flake edges were sharpened for cutting
● Had a large variety of tools for many different jobs
● Tools shaped to fit into handles
● Tools not just made of stone many other materials
used including bone, anthers, guts plant fibres etc
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● These tools allowed hunters to kill much larger prey and process it quickly, as well as
allowed them to preserve the food
● Animal hides would be stretched over wood to make tent type structures, they also
made cloths out of the hides
Trends in human cultural evolution between hominins with respect to methods of
acquiring food
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Later they
followed the herds around eventually they became less nomadic
● This gave early humans a greater variety of food which was of a better quality and
close by
● First animals to be domesticated were dos then goats, sheep and pigs
● First plants were wild wheat about 18,000 years ago
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● As this happened their dwellings became more permanent and larger
Advantages of farming
● Food supply easier to obtain with a much more dependable food source
● Fewer people died of starvation
● Fewer people needed to work at providing food for many
● Specialised skills able to be developed by those not involved in getting food and
while living in a permanent settlement meaning they get better at their “job”
benefiting the whole group
● As people became more skilled at farming they developed more permanent
settlements at the best sites near sources of water
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● As a result of this they had more time to develop other skills such as art, pottery etc
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g
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g
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● Growing crops etc
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Discovery and development of fire
Fire was first used by Homo Erectus and the use of it meant that they could gather around
the fire together and provided light at night for longer days where erectus could have spent
more time in communication and thinking through the days problems
Benefits of using fire
● at night/in colder areas
● anti-predator defences eg
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● able to keep warm in cooler regions
● Use of fire lead to better / stronger tools more successful hunting and increased
food
● Use of fire to cook food / meat to access additional protein / energy
● Use of fire as protection from predatory animals
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The fire discovered by H
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Fish hooks or
spears to catch fish and nets and snares to catch larger prey
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​Shelter​ brings:
● planning
● communication
● cooperative behaviour
● division of labour

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suggests a larger group (NOT just communities)

Comfort: Clothing
Neanderthal​ were the first to make clothing with animal hides and skin
Later, when tools started getting more advanced in the the ​Homo Sapien and as early as
Neanderthal ​era, the tools started getting more refined, meaning that needles and other
things could be made to further refine clothing
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Adults hunted and left young behind, and then brought all produce back to be shared
Sharing of food lead to complex societies
Clearly defined by the time of ​Homo erectus
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Homo habilis- ​made simple shelters
Homo Erectus- ​built huts with wooden poles for support
Homo heidelbergensis- ​built huts
Homo neanderthalensis and H
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They also made cloths out of the hides
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erectus ​moved out of Africa to other parts of the World relatively quickly
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sapiens​:
Multiregional and Out of Africa
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8 MYA and spread to Europe and
Asia

● In the three areas ​H
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sapiens,​ with some genetic
contact and gene
● flow between populations in the different areas;
● H
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Erectus
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Erectus about 1
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heidelbergensis
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Evidence to support this hypothesis:
● In a number of places, there are fossils intermediate between H
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sapiens
● Modern Europeans have on average about 2
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● Some transitional fossils have been found in many places esp the Asian fossils which
show a clear transition from older hominid to modern ​H sapiens
● High levels of gene flow would be needed for this hypothesis to be correct which is
not very likely
This hypothesis is highly questioned based on the more recent genetic research especially
the use of mtDNA and Y chromosome DNA (see below)
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However when mtDNA (mitochondrial
DNA) and Y chromosome DNA is analysed there was less variation than expected
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Sapiens
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Erectus group
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Erectus populations they came across
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sapiens​ ​evolved in Africa up until 170,000 years ago, and then colonised the world,
replacing other hominin species as he went
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Sapiens fossils are found in Ethiopia- Africa, 195,000 years old
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Sapiens fossils outside Africa are 120,000 years old and found in the part
of Asia nearest Africa
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Sapiens
fossils are less than 60,000 years old
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● The strongest evidence comes from the studies of mtDNA

Evidence from mtDNA: ‘Mitochondrial Eve’
● Identical to your mother and inherited only from your mum
● The only way it can change is through mutation, so without it you should have the
same mtDNA as your mother’s mother's mother, etc
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Present people are all
descendants of this one woman- a ‘mitochondrial eve’
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Y Chromosome
While mitochondrial DNA is passed down from mother to child, Y chromosomes are
only passed down from father to son
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Assimilation ​(partial replacement, new theory)
Modern humans evolved in Africa and spread across the world,​interbreeding ​at times with
other hominins that had left Africa earlier, such as Denisovans and Neanderthals

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