This summary contains all the necessary information for Hominin Evolution (Australopithecus, Homo, etc.) It also contains the Out of Africa Hypothesis and how Fossils help to prove evolution.
EVOLUTION (part 2)
Similarities between African Apes and Humans
1. Upright posture
2. Long upper arms
3. Freely rotating arms
4. Rotating elbow joint
5. Rotating hands
6. Nails in stead of claws
7. Big skulls in relation to body mass
8. Eyes pointing forward
9. Eyes with cones (can see colour)
10. Sexual dimorphism
11. Smaller olfactory brain area
12. Enlarged parts of brain that control hands and eyes
13. Only 2 mammary glands
Benefits of bipedalism
• Bigger field of vision to see predators and food
• Hands are free to use to hunt/use tools
• Smaller surface exposed to sun = smaller risk of overheating
Anatomical Differences between African apes and Humans
AFRICAN APE HUMAN
Bipedalism 1. Quadripedal Bipedal
(Walks upright)
2. Foramen magnum Foramen magnum
towards back central
3. C-shaped spine S-shaped spine (2 kinks)
Brain size 4. Smaller cranium Bigger cranium &
cerebral cortex
Teeth 5. Big canines Small canines
Diastema present No diastema
Thick enamel layer Thin enamel layer
Big molars Small molars
Prognathism 6. More prognathic (jaw Less prognathic (flat
extends further) face)
Pallet shape 7. Elongated, U-shaped Wider, more round V-
shaped
Cranial ridges 8. Present Absent
Brow ridges 9. Well-developed Smaller
10. Arms are longer & Arms shorter and
stronger than legs weaker than legs
11. Opposing big toe No opposing big toe
12. Smaller, weaker knee Bigger, stronger knee
joint joint
13. Flat feet Heightened bridge
THREE MAIN GENERA OF HOMININS
Christiaan de Beer (2018)
, 1. Ardipithecus
• Small (weigh only 50kg)
• Only 17 known fossils
• Transitional fossil between apes and humans
i. Ardipithecus ramidus
• 4.4m years ago in Awash region (Ethiopia)
• Discovered by Tim White
• Characteristics
o Small brain (350cm3)
o Forward foramen magnum Ardi
o Prognathic face & prominent brow ridges
o Teeth indicate diet based on plants & fruits
o Pelvis indicates that it is a transitional fossil
(bipedal & opposing big toe)
2. Australopithecus
• Small body & brain
• Big teeth
• Transitional fossil
• Different species found in Eastern & Southern Africa
i. Australopithecus afarensis
• 4-2,7m years ago in Ethiopia, Kenia, Tanzania
• Discovered by Donald Johnson
• Characteristics
o Small brain (550cm3)
o Forward foramen magnum
o Very prognathic face
o Prominent brow ridges
o Absent cranial ridges
o Large pointed canines Lucy
o Long arms
o Rigid feet
ii. Australopithecus africanus
• 3-2m years ago in Sterkfontein
• Discovered by Raymond Dart
• Characteristics
o Brain size of 645cm3
o Forward foramen magnum
o Prognathic face
o Prominent brow ridges
o No cranial ridges
o Long arms Taung Child
o Rigid feet
iii. Australopithecus sediba
• 1,9-1,8m years ago in Malapa Cave (cradle of human kind)
• Discovered by Lee Berger
• Characteristics
o Brain size of 420cm3
o Forward foramen magnum
o Less prognathic face
Christiaan de Beer (2018)
Karabo
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