2. Origins of Hominids
◊ Most crucial change was Bipedal
Locomotion
◊ Other changes include
• Expansion of the brain, larger birth canal,
reduction of face, teeth and jaws
◊All of these occurred 2 million yrs. After
bipedalism
◊ Journal Entry 1
3. Why did Bipedalism occur?
◊ See farther
◊ Carry food
◊ Carry tools and weapons
4. Australopithecines
◊ First definite Hominids
◊ Genus of Hominids until C. 2 Mill yrs.
Ago
◊ Somewhere b/t 3 and 4 mill. yrs ago.
◊ At Laetoli footprints found proving
bipedal locomotion
◊ Although Bipedal, still may have spent
time in trees for sleep and shelter
5. Types of Species
◊ Australopithecus afarensis
◊ Australopithecus africanus
◊ Australopithecus robustus
◊ There are more Think of hominids as
a Bush, not a timeline!
6. Australopithecus Afarensis
◊ Debate as to whether diff. species or
not
◊ Footprints found to prove bipedalism
◊ Between 3 and 4 million years ago
8. Afarensis vs. Africanus
◊ Features of skull, teeth, and jaws that
are less apelike in africanus
◊ Some debate different species
9. Australopithecus robustus
◊ 2-1 million years ago
◊ Larger molars and premolars
◊ Smaller canines
◊ Well-developed cranial crests and ridges
◊ Much heavier
◊ Taller: 4.5- 5 ft. tall
12. Changes
◊ Expansion of brain
◊ Reduction of face, teeth, and jaws
◊ Babies born less mature at birth
◊ Journal Entry #2
13. Expansion of the brain
◊ Had relatively small cranial capacities
◊ Reason?
• Why would brain size have increased? (Think
Evolution types)
◊ Possible reasons:
• Increased as a result of tool making
14. Reduction of Face, Teeth, and
Jaws
◊ Lower face not as protruding
◊ Reduction in size of
• Face
• Cheek bone
• Jaw
15. Now on to species of Homo
◊ Different ideas on how Homo genus
evolved
◊ Some say from Africanus
◊ Some say from Afarensis
◊ About 2 millions years ago
16. Homo habilis
◊ Larger brain absolutely and relatively
than Australopithecus
◊ Found in East Africa
◊ Slightly Larger and more developed
brain
◊ Stone tools?
17. Homo erectus
◊ 1.6 to 1.3 millions years ago
◊ Skull generally long, low, and thickly
walled
◊ Flat frontal face
◊ Prominent brow ridges
◊ Relatively small teeth modern
arrangement
18. Cont…
◊ Fully developed vision area of brain
◊ Larger areas of speech, sensory,
memory and motor areas of brain
◊ Neck down, almost same as Homo
sapiens
19. Fire
◊ Fire first appears 1.5 mill. Years ago
◊ Only able to spread out after
development of fire
◊ Journal Entry
20. Stone tools
◊ Acheulean “hand axe”
• 1.5 mil. Years ago
• Used for butchering, digging, pounding
◊ Toolmaker first shaped the core, and
prepared a striking platform at one end
◊ Knock off flakes
21. Hunting
◊ Homo erectus began to hunt medium
sized animals
• Spears, stone throwing, and fire
• Needed to plan and work in groups
