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The Paleocene
- (65mya-58mya)
- Earth was heavily forested; cool and wet climate
- Many mammals evolved (insectivores)
- Scarce evidence of early primates
- Fossil remains of jaws and teeth
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The Eocene
- 58mya-34mya
- Earliest undisputed primates emerge
- >200 primate species identified
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The Oligocene
- 43mya-24mya
- Cool and dry climate
- North America seperates from Eurasia
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The Miocene
- 24mya-5mya
- ~100 ape scecies roamed the old world
- Monkeys and apes diverge
- Human line and other apes split ~8mya
- Ardiphithecus ramidus: earliest known hominid (~5.8 mya)
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Hypotheses for Bipedal Evolution
- 1. Life in the African savanna
- 2. Free hands to carry food, carry children, acquire food, eating more efficiently
- 3. Allows for long-distance travel
- 4. Body temperautre regulation
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Skeletal Evidence for Bipedalism
- 1. Head balanced on backbone
- 2. Lack of powerful neck muscles
- 3. "S" shaped spine
- 4. Muscle attachments on femur
- 5. Legs angle in toward each other
- 6. Long legs
- 7. Foramen magnum
- 8. Low, bowl-shaped, broad pelvis
- 9. Larger ankle bones and arched feet
- 10. No divergent big toe
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The Pilocene
- 5mya-2mya
- Hominid: member of the family Hominidae (bipedal)
- Two genera in the hominid family:
- -Australiphithecus (all extinct)
- -Homo (both extinct and extant)
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Australopithecine Characteristics
- Facial prognathism
- Prominent brow ridges
- Big incisors and canine teeth
- Thickly enameled teeth
- Small Brained
- Sexually dimorphic
- Short stature (<4 feet tall)
- Bipedal
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Selam the Dikika Baby
- 3.3 million year old infant (3 years old)
- Ethiopia
- Very complete skeleton, including face, shoulder blades, hyoid bone
- Shoulder blades are gorilla-like
- Tree-dweller and biped?
- Discovery of a child gives clues to infant development
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Laetoli footprints
- Found by Mary Leakey
- Footprints in volcanic ash that were covered and preserved
- Weight distribution = modern human
- ~3.6mya
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Homo habilis & Oldowan Tools: The Lower Paleolithic
- ~2.3mya: identifiable stone tools
- Tool use: cultural behavior
- Stone tools asscoiated with H. habilis
- Identified by Mary Leakey in Tanzania, Kenya, Tanzania, Ethiopea, South Africa, Israel
- Percussion Flaking
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Uses for Oldowan tools
- 1. Cutting
- 2. Smashing bones
- 3. Digging
- 4. Working wood (?)
- 5. Scraping (?)
- 6. Defense (?)
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Tools weren't just rocks because...
- 1. Exotic raw materials
- 2. Flaking patterns
- 3. Often found with animal bones
- 4. Not water or glacier worn
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