HOMINID STUDIES
Hominid studies
The primate order:
• 300 or more species
• Third most diverse order of mammals after rodents and bats
• Six subgroups: lemurs, lorises, tarsiers, new world primates, old world
primates
What evidence is there that primates have a common ancestor?
Ø Biogeographical evidence of a common ancestor
Ø Gondwanaland
Ø Then continental drift played an important part in initial geographical
subdivisions within primates
Ø Most present-day primates are arboreal i.e. living in trees
Ø Primates have many characteristics that are adaptations to this arboreal way
of life
1. They have kept the clavicle or collarbone = important part of shoulder joint
2. They have long, slender limbs that rotate freely at the shoulders and hips
3. Many have mobile opposable thumbs = hold on to branches
The following are other characteristics that all primates share:
• An enlarged and complex brain
• Flattened face and reduced snout with reduced sense of smell (rely on vision
more than smell)
• Eyes that face forward (eyes visual fields overlap to give stereoscopic vision)
• Digits with flat nails
• Molar and premolar teeth with cusps that are low and rounded
• Complex social behaviour usually only one offspring at a time and extended
care for the young
Genetic evidence of a common ancestor for primates is slowly emerging. Primates:
o Share a large percentage of their DNA
o Have a larger number of olfactory-receptor pseudo-genes than non-primates
o Have full trichromatic colour vision (perceive red, green and blue)
Sequences of human evolution
Humans belong to the order primates
v Prosimians (before apes)
v Hominoidea (great apes) – monkeys, African apes and humans
v Gorillini v Hominini
1
, HOMINID STUDIES
Genetic analysis combined with fossil evidence indicates that:
§ Hominidae family split into subfamilies, homininae and poginae
§ Homininae subfamily split into two tribes, hominini and gorillini
§ Hominini tribe split into the genera, homo, australopithecines and Pan
Evidence for a common ancestor for living hominids
If there is a common ancestor we will be able to trace the evolution of humans from
this ancestor
Ø Scientists use fossil records and genetics (chromosomal DNA and
mitochondrial DNA)
AFRICAN APES AND HUMANS – COMPARED
Humans did not evolve from African apes rather the two groups evolved from a
common ancestor
Ø What are their anatomical similarities?
Þ Have an upright posture
Þ Lack external tails
Þ Have freely rotating arms
Þ Have hands with opposable thumb that, with other fingers = grasp
objects
Þ Have digits (hands and fingers) with flat nails
Þ Eyes that face forward so eyes visual fields overlap
Þ Have molar and premolar teeth with low and rounded cusps
Þ Eyes with cones for colour vision
Þ Sexually dimorphic
Þ Have large brain compared to body mass
Ø What are their anatomical differences?
Þ Have been evolving separately for 6 million years
Þ During that time humans experienced different selection pressures
such as climate change, different diet and effect of bipedal locomotion
Ø Skeletal differences
Apes have:
Ø Arms usually longer than legs
Ø Fingers and toes that are long and curved for grasping branches
Ø Big toes that are divergent
Ø Ilia (hipbones) that are large, elongated and parallel to spinal column
Ø A bow-shaped (less-curved) spine
2
, HOMINID STUDIES
Humans have
Ø Arms that are shorter and weaker than the legs
Ø Fingers and toes that are short and straight
Ø Thumbs that can grasp objects precisely and firmly between the tips of
fingers and thumb
Ø A shorter, broader and more bowl-shaped pelvis
Ø Longer femurs (thighbones) set farther apart at the hips
Ø Feet that have: large strong heel, tiny toes with large big toe moved
into line with the others, longer feet with a stable arch
Ø Spine curvature that has two major curves, the thoracic and lumbar
Ø Brain differences
• Humans have a larger brain than that of the African ape especially the
cerebral cortex
• Average capacity of adult chimpanzee brain is 365cc
• Modern human brain is 1350cc
• Humans have more white matter = more connections between nerve
cells and therefore greater ability to process information
Larger more complex brain is responsible for development of unique
behavioural qualities of humans, which include:
• Using their hands with greater dexterity to make simple tools
• Use and control of fire
• Use of a highly developed language
Ø Skull differences
o Humans do not have a pronounced brow ridge of an African ape
o Foramen magnum in humans is found centrally under the skull
whereas in apes is at the rear of the skull
o Spine of human connects with the skull underneath and near the
centre so that the head is held firmly upright and body’s centre of
gravity is directly over the legs
o Humans have large braincase, small jaws, a nearly vertical face and
chin but African apes have opposite
o Canine teeth of humans are relatively small, whereas those of apes
are large and pointed and project beyond the other teeth
3
Hominid studies
The primate order:
• 300 or more species
• Third most diverse order of mammals after rodents and bats
• Six subgroups: lemurs, lorises, tarsiers, new world primates, old world
primates
What evidence is there that primates have a common ancestor?
Ø Biogeographical evidence of a common ancestor
Ø Gondwanaland
Ø Then continental drift played an important part in initial geographical
subdivisions within primates
Ø Most present-day primates are arboreal i.e. living in trees
Ø Primates have many characteristics that are adaptations to this arboreal way
of life
1. They have kept the clavicle or collarbone = important part of shoulder joint
2. They have long, slender limbs that rotate freely at the shoulders and hips
3. Many have mobile opposable thumbs = hold on to branches
The following are other characteristics that all primates share:
• An enlarged and complex brain
• Flattened face and reduced snout with reduced sense of smell (rely on vision
more than smell)
• Eyes that face forward (eyes visual fields overlap to give stereoscopic vision)
• Digits with flat nails
• Molar and premolar teeth with cusps that are low and rounded
• Complex social behaviour usually only one offspring at a time and extended
care for the young
Genetic evidence of a common ancestor for primates is slowly emerging. Primates:
o Share a large percentage of their DNA
o Have a larger number of olfactory-receptor pseudo-genes than non-primates
o Have full trichromatic colour vision (perceive red, green and blue)
Sequences of human evolution
Humans belong to the order primates
v Prosimians (before apes)
v Hominoidea (great apes) – monkeys, African apes and humans
v Gorillini v Hominini
1
, HOMINID STUDIES
Genetic analysis combined with fossil evidence indicates that:
§ Hominidae family split into subfamilies, homininae and poginae
§ Homininae subfamily split into two tribes, hominini and gorillini
§ Hominini tribe split into the genera, homo, australopithecines and Pan
Evidence for a common ancestor for living hominids
If there is a common ancestor we will be able to trace the evolution of humans from
this ancestor
Ø Scientists use fossil records and genetics (chromosomal DNA and
mitochondrial DNA)
AFRICAN APES AND HUMANS – COMPARED
Humans did not evolve from African apes rather the two groups evolved from a
common ancestor
Ø What are their anatomical similarities?
Þ Have an upright posture
Þ Lack external tails
Þ Have freely rotating arms
Þ Have hands with opposable thumb that, with other fingers = grasp
objects
Þ Have digits (hands and fingers) with flat nails
Þ Eyes that face forward so eyes visual fields overlap
Þ Have molar and premolar teeth with low and rounded cusps
Þ Eyes with cones for colour vision
Þ Sexually dimorphic
Þ Have large brain compared to body mass
Ø What are their anatomical differences?
Þ Have been evolving separately for 6 million years
Þ During that time humans experienced different selection pressures
such as climate change, different diet and effect of bipedal locomotion
Ø Skeletal differences
Apes have:
Ø Arms usually longer than legs
Ø Fingers and toes that are long and curved for grasping branches
Ø Big toes that are divergent
Ø Ilia (hipbones) that are large, elongated and parallel to spinal column
Ø A bow-shaped (less-curved) spine
2
, HOMINID STUDIES
Humans have
Ø Arms that are shorter and weaker than the legs
Ø Fingers and toes that are short and straight
Ø Thumbs that can grasp objects precisely and firmly between the tips of
fingers and thumb
Ø A shorter, broader and more bowl-shaped pelvis
Ø Longer femurs (thighbones) set farther apart at the hips
Ø Feet that have: large strong heel, tiny toes with large big toe moved
into line with the others, longer feet with a stable arch
Ø Spine curvature that has two major curves, the thoracic and lumbar
Ø Brain differences
• Humans have a larger brain than that of the African ape especially the
cerebral cortex
• Average capacity of adult chimpanzee brain is 365cc
• Modern human brain is 1350cc
• Humans have more white matter = more connections between nerve
cells and therefore greater ability to process information
Larger more complex brain is responsible for development of unique
behavioural qualities of humans, which include:
• Using their hands with greater dexterity to make simple tools
• Use and control of fire
• Use of a highly developed language
Ø Skull differences
o Humans do not have a pronounced brow ridge of an African ape
o Foramen magnum in humans is found centrally under the skull
whereas in apes is at the rear of the skull
o Spine of human connects with the skull underneath and near the
centre so that the head is held firmly upright and body’s centre of
gravity is directly over the legs
o Humans have large braincase, small jaws, a nearly vertical face and
chin but African apes have opposite
o Canine teeth of humans are relatively small, whereas those of apes
are large and pointed and project beyond the other teeth
3
