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Lecture

Origins


Department
Anthropology
Course Code
ANT203Y1
Professor
Brooke Crowley

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ANT203 November 30th, 2010
Geography:
- Continental drift has led to environment shifts.
depends on position of continents, different climates
the position of the plates influenced the origin and evolution of
primates
- 65 millions years ago the Earths surfaced looked a lot different than it does
today.
- North America and Europe were still attached ( they were once connected )
lush forests; ideal place for primates to evolve
find primate fossils here
- Mediterranean Sea was a lot smaller
- affected climates in Africa and Europe
Primate Origins:
- hypothesis to explain primate origins
1) Arboreal habitat
- unique primate characteristics evolved as a responses to an arboreal
lifestyle
- grasping hands, feet
- opposable hallux
- stereoscopic vision
2) Visual predation hypothesis
- adaptive stage preceding arboreal adaptation
- primates originated as nocturnal visual predators
- evolved hand/eye coordination
- grasping based on tactile pads
- opposable hallux
- stereoscopic vision
- When arboreal and diurnal niches opened primates were able to take
advantage
because of their preexisting adaptations
3) Angiosperm coevolution
- primate complex evolved in response to a dramatic diversification in
fruit-
bearing plants
- Grasping: cling to branches while eating fruit
- Vision: locating food in a 3D world
Which is correct?
www.notesolution.com

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all could have been selective pressures on primate adaptations
othere was an ADAPTIVE SHIFT
owe start seeing the general primate suite of characters
approx. 53 mya but dont know the precise selective
pressures(s)
When do we see the first primate-like creatures in the fossil record?
- Paleocene: radiation of placental mammals
1) Scandentia tree shrews
2) Dermoptera colugos or flying lemurs
3) Chiroptera bats
4) Insectivora insectivores (little shrews)
5) Rodentia rodents
- origins debated
- big eyes, visual orientated; arboreal lifestyle
When do we see the first primate-like creatures in the fossil record?
Plesiadapiforms = primate-like mammals (but not true primates)
Paleocene to early Eocene (N. America, Europe)
Have a mosaic of primate features, but not entire suite
Plesiadapids: divergent big toe, similar teeth, to living primates,
but no post-orbital bar & smaller brain
When do we see the first true primate in the fossil record?
Adapiforms (Adapidae), Middle Eocene, ~45 mya
Found in Europe & N. America and less frequently in Asia & Africa
oShorter snouts than Plesiadapids
oPostorbital bar
oGrasping digits with nails
oTeeth mainly suggest folivory and frugivory
oSmall eye orbits (possibly diurnal)
These earliest primates were strepsirrhine-like
Haplorhine Origins:
Haplorhines originated from a tarsier-like ancestor
www.notesolution.com
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