The document summarizes key developments in hominid evolution from the earliest hominids to Neanderthals. It notes that bipedal locomotion first emerged around 2 million years ago in early hominids like Australopithecus. This was followed by other changes like brain expansion and changes to the face, teeth and jaws. Early hominid species included Australopithecus afarensis, Australopithecus africanus, and the more robust Australopithecus robustus. Around 2 million years ago, the first species of the genus Homo evolved, including Homo habilis and Homo erectus, which had larger brains and used stone tools. Homo erect

1. Hominid Evolution

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

7. Australopithecus Africanus
◊ Jaw of ape
◊ Teeth of humans
◊ S-shape spine similar to man

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

10. Ancestor?
◊ Australopithecus robustus is not
thought to be an ancestor to the Homo
species
◊ Lived during same relative time as
Homo species

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

24. Neanderthal
◊ Becoming Human