Term
| earliest evidence of hominins (time scale) |
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Definition
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Term
| what theories did we have in the past concerning our closest relatives? |
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Definition
• Pongids vs hominids.
o Pongids include chimps, gorillas, orangutans.
• Where pongids and hominids meet at top of triangle there was Ramapithecus(17myrs)--had rounded jaw (instead of square jaw like chimps and gorillas), thickened tooth enamel.
o The age of ramapithecus made us think the split between humans and apes was long ago.
o Ramapithecus was renamed sivapithecus since it was obvious it was once a orangutan. |
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Term
| Morris Goodman and molecular |
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Definition
Human blood proteins reacted with chimps and gorillas vice versa. Orangutans became the outgroup, not humans--most distantly related.
• We are more closely related to chimps rather than chimps to orangutans. |
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Term
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Definition
• Cosmic radiation causes mutations, and we are being constantly being exposed to cosmic radiation--if we know when species split we can establish rate of mutation along with genetic distance.
• Saw humans closely related to chimps, gorillas come next, orangutan after that, gibbons next, and finally old world monkeys.
• Shocking to see we are more closely to chimps than chimps are related to orangutans. |
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Term
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Definition
•Chimps and Gorillas have thin enamel
•Humans have thick enamel.
• Maybe chimps and gorillas are more closely related which makes us wonder if enamel is a derived or primitive---
The answer is enamel thickness is an independently derived characteristic.
(orangutans for example have more cells that produce enamel while we just produce it longer) |
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Term
| Veryyyyyy little fossil record for chimps and gorillas. --Why so? |
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Definition
• Maybe they confuse the human fossils when they are really chimp and gorilla fossils.
• They are looking in places where human evolution occurred, not for them.
• The gorillas and chimps live in a place that lives in places that are bad for fossil making--wet climates |
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Term
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Definition
• Sahelanthropus tchadensis
• Ardipithecus kaddaba
• Orrorin tugenensis |
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Term
| Sahelanthropus tchadensis |
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Definition
o Comes from chad, tip of Sahara
o Used to be lake in chad, so guy who found fossil looked on ancient shore lines.
o Flat face
o Placement of foramen magnum means upright position
o No bigger of a brain than a chimp |
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Term
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Definition
o Derived morphology based on toes.
o Looks like what you would expect of a common ancestor.
o Says that sahelantropus is a kaddaba. |
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Definition
o From hills of Kenya
o Thigh bones and teeth
o Millennium man!
o Head of femur suggests they are bipedal |
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Term
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Definition
• brain enlargement
• increasing terrestriality (bipedality but still haven’t left trees), big toe coming into line
• enamel getting progressively thicker, larger and flatter teeth |
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