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Feature

Primate Characteristic
Not specialised for
particular environment
Generally unspecialised
Pentadactyl – five fingers
or toes

CHARACTERISTICS OF PRIMATES (Chapter 19)
Purpose/Function
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All for great diversity in use

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Allow for great diversity in use

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Five highly mobile digit which relates to the arboreal (tree like) way of life

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Claws limits grasping as they prevent opposable surfaces from coming
together
Primates need to be able to find and maintain secure grip on trees (with nails)

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Friction ridges are known as fingerprints
Allow for better grip and manipulate objects as they have sense receptors
...


Forward facing for 3D
(stereoscopic) vision



Forward facing eyes allow field of vision of each eye to overlap
 Therefore distance can be judged more accurately

More able to distinguish
colours

Body
Limbs

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Rod = vision in dim light
Cone = fine visual discrimination and colour vision

Nails instead of claws
Hands/Feet

Grasping fingers and toes
with friction ridges for
gripping
Opposable first digit

Eyes

Sense of
Smell
(Olfaction)

Very poor



Human have five fingers
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Nail instead of claws

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More opposable

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Better sight = decrease reliance on smell (due to
change in shape of skull)
Eye become more forward facing (allowing
stereoscopic vision)
Forward facing eye = narrower field of view ∴ have
highly mobile head and neck
Have rod and cone in retina of eye
Improve nerve connection of rod and cone to brain =
more acute and coordinated eye sight = stereoscopic
v
...
cortex enable them to move about and locate food and develop
special skills (eg
...

Primates are tree liver therefore they need to
accurately judge distance between trees or else
the consequence will be fatal
...


Lemurs and lorises have unusual specialisation
of incisor teeth where their lower front
incisors, and sometimes the canine form
“dental comb” for grooming fur
...

Increase size and complexity of brain from
lemurs to humans
...

Ape fed mother’s milk for three of four years
then they can continue to get her protection for
another 6 or more years
...
4

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Jaw Bone



Vertebral
Column
19
...
7



Femur
19
...
9

Legs
19
...
column
...
Balance achieves with
Protruding jaw

Flatter facial profile
minimum muscular effort
...
column became for “S” shaped
 provides upright stance to allow head balance on top
which form forward jutting curve “C” shape
...

Longer and narrower
pregnancy

Female broader than male to allow passage of infant at birth

Large head to femur = carrying angle
Carrying angle form due to change in shape and orientation of pelvis which
Form right angle
 Greater stability when walking
result in hip joint being directly under the trunk and head
...

 At chest level
 At pelvis level
Primitive Primate

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RELATIVE SIZE OF CEREBRAL CORTEX (Chapter 20)
Difference in brain size associated with cerebrum
Outer cerebrum, cerebral cortex, shows greatest development in human
Human larger brain size = large brain case/cranium
∴ Brow ridge tends to be vertical and less prominent
Less prominent brow ridge and shortening of snout = human has flatter face (though nose bone is still protruding)
An evolutionary trend in hominins

PROGNATHISM & DENTITION (Chapter 20)
Compared to other primate, human dentition = very distinctive
Human’s canine are align with other teeth and look more like incisors
Small canine and incisors = less space in jaw
∴ Tooth row, dental arcade, evolve into parabolic shape instead of “U” shaped
Decrease in canine size = no need for diastema
 Diastema allow closing of jaw with large canines
Molar and premolar become smaller due to change in diet
 Where diet consist of softer food including meat, then cooked food

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