1. Early Hominids January 31, 2005

2. Part I: Hominid Phylogeny Australopithecus –africanus –afarensis –robustus Homo –habilis –erectus –sapiens

3. Hominid Phylogeny

5. Australopithecus A. africanus Raymond Dart’s “Taung Child” 3.0-2.5 mya Bipedal Small brain Sexual dimorphism suggests polygyny Partially arboreal Worked in groups

6. Australopithecus A. afarensis “Lucy” Fan shaped pelvis 3.8-3.0 mya

7. Australopithecus Gracile A. afarensis A. africanus? Robust A. robustus A. boisei A. africanus? Folivore: large molars and sagittal crest Small canines Little sexual dimorphism

8. Part II: When did this happen? Geologic time scale:

9. How do we know? Relative Dating –Statigraphy –Glaciations –Fluorine analysis –Dendrochronology

10. How do we know? Absolute Dating –Carbon 14 (organics, up to 40,000 years) –Potassium Argon (volcanic, over 500,000) –Uranium Series (minerals b/w 1k and 1m) –Thermoluminescence (rocks & minerals b/w 5k and 1 mya) –Electron Spin Resonance (rocks & minerals b/w 1k and 1mya)

11. How do we know? Calendars Historical accounts

12. Part III: Why did this happen? Ecology: 1) Relationships between organisms and environment. 2) Relationships between human groups and their physical and social environments.

13. Climactic Shifts

14. Bipedalism Energy efficient locomotion Food gathering Avoiding predators Provisioning offspring Free hands (tools) Tracking prey

15. Skeletal Comparison

17. Brain Size Homo sapiens sapiens: 1,200-1,350 Modern Chimpanzee: 390 A. afarensis: 430 A. africanus: 490 A. robustus: 540 A. boisei: 490 (Measured in cubic centimeters)

18. Skeletal Comparison Human Chimp

19. Skeletal Comparison Robust Australopithecus Gracile Australopithecus

20. Dental Comparison Modern Chimp A.afarensisH. sapiens Upper jaw

21. Part IV: What does it mean? Killer Ape –Osteo-donto-keratic tools Man the scavenger –Probably vegetarian or omnivorous

22. What does it mean? Savannah hypothesis Variable selection –Phenotypic plasticity

23. What does it mean? Bipedalism or Intelligence? Piltdown hoax

24. What does it mean? Piltdown hoax