ANT101H5 Lecture Notes - Orrorin, Femur, Sahelanthropus

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14 Feb 2013
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Chapter 9 Lecture
Early Primate Evolution
Eocene 56-34/33 mya
Eo = first, earliest
1st primates
Prosimian Radiation
o Radiation means that species that diversifies into a diversity of niches
o Lemurs and loires ancestors
1st Anthropoids
o Ancestors of monkeys, apes an humans
Oligocene 33-23 mya
Anthropoid Radiation
o Lots of different kinds of monkeys, apes and humans (ancestors not
modern)
Start to see a lot more animal species that are more like anthropoids
Miocene 23-5 mya
1st Hominoids
o Ancestor of apes and human (and all extinct human ancestors)
Hominoid Radiation
o Wide diversity these kinds of animals that fossil apes and humans
would have done
Main points are on page 202
Hominoids include the apes
Figure 9-3
Figure 9-4 Miocene Hominoid Distribution
o Only in the Old World
They are hominoids
More closely related to the hominins than old World monkeys
Chimp size or bigger larger body (trend for the primates)
Most of them are so derived, that they are specialized into an adaptive niche
We haven’t found the most direct ancestors for the hominoids
EXCEPTION: celopithicus might be the ancestor for the organatang
Hominin Evolution Overview
We are interested in our direct ancestors, hominins
o Apes are not included
Hominin vs. Hominid
Figure 9-8b
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Ancestry is more complicated (as you can see in the lower chart)
Hominids refer to a larger group, while hominins are our species
Mosaic Evolution
- Figure 9.7 is a really good summary
- Mosaic Evolution = little pieces are added to make a whole picture
- The earliest hominins are approx. 5 mya (based on fossil evidence)
Bipedal Locomotion
o Remains the number one classification trait for hominin
o Clear evidence of bipedal adaptation was from 4 mya
Brain encephalization
o Is a gradual process
o Overall trend is for the size to increase (not the brain, but different
parts of the brain gets bigger)
o Take off after around 2 mya
o **Encephalization = brain to body size ratio increases greatly
overtime
Dentition
o All hominins overtime actually have their front teeth decrease in time
o We do not have big canines and incisors our teeth are relatively the
same size
o True from 1 mya
Cultural behavior (seen via tools)
o Very imporant for hominins
o Shows a gradual increase through time
Biocultural Evolution
Process of biocultural evolution
Hominins are clearly bioculturally adapting
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