Final Exam Flashcards
Shared Traits of Hominini
-bipedality
-increased brain-to-body size (encephalization)
-anterior foramen magnum
-no honing premolar
-reduced canines
-reduced sexual dimorphism
-intermembral index 70-90
Sahelanthropus tchadensis “Toumai”
-Date and location
-earliest known human ancestor, 7.6-8 mya
-Found in Chad
Sahelanthropus tchadensis “Toumai”
-Traits
-massive brow ridge***
-small brain (320-380 cc)
-less prognathic
-large nuchal crest
-anterior foramen magnum
-habitat: gallery forest along a river surrounded by grassland
Orrorin tugenesis
dates and location(s)
-5.9-5.7 mya (dated by argon-argon)
-found in the Tugen hills in Kenya
Orrorin tugenesis
traits
-thick enamel (implies eating nuts, seeds)
-angle of femoral head indicates bipedality
-arms = arboreal
-legs = terrestrial
The Pliocene climate
5.3-2.6 mya
global cooling after miocene
this cooling and drying is why grasslands and Savanas became more common
Ardipithecus
two species
Ardipithecus kadabba
Ardipithecus ramidus
Ardipithecus kadabba
5.8-5.2 mya
large, ape like canines
Ardipithecus ramidus
dates and location
4.5-4.3 mya
Eastern Africa
Ardipithecus ramidus
Important traits
-has “hand-foot”**
-small brain (300-350 cc)
-anterior foramen magnum
-arboreal arms and hands
-bipedal pelvis and femur
-abducted hallux, unique morphology to bring hallux inwards
-thin enamel (eats c4 plants such as grass and wheat)
-monomorphic canines (pair bonding)
A brief history of “Australopithecine” discoveries
-originally found in 1924– anterior foramen magnum with enbocast revealing human like brain
-originally not believed to be real due to Darwin’s “Piltdown” man scandal (1912)
-proved that it was legit and bipedal, very strong evidence that it is human ancestor
Australopithecine shared features
-small, ape like brain and face structure
-clearly bipedal
-ape arms
-mix of modern ape and human features
Australopithecus africanus
dates and location
3.3-2.1 mya
South Africa
Australopithecus africanus
Important Traits
primitive arms, but more advanced than A. afarensis
larger brain, human like pelvis
-bipedal
Difference between gracile (Australopithecus) and robust (Paranthropus) “Australopithecines
-A. africanus and A. afarensis had much more gracile skulls than Paranthropus
-post-cranially the same but cranially very different
Paranthropus shared features
huge ass teeth and face
Paranthropus aethiopicus
Dates and Location
2.7-2.3 mya (same as homo)
-Kenya/Ethiopia, evolving in response to climate change
Paranthropus aethiopicus
Important traits
HUGE crest
very prognathic
Paranthropus boisei
Dates and Location
2.5-1.4 mya
East Africa– Ethiopia to Malawi
Paranthropus boisei
Important traits
-flexed cranium (face is “flexed” inwards like a dish)
-anterior crest
-500-540 cc (bigger brain
Paranthropus robustus
Dates and Location
1.8-1.0 mya
South Africa
Paranthropus robustus
Important traits
-Least robust out of three
-reduction of teeth size due to warming climate and different foods
-very similar to P. boisei but less robust
Australopith Chronology & Biogeography
homo Paran.
\ /
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Au.
Au. > early Homo > Paran. > Au. die out > Homo erectus > Paran. die out
Adaptive radiation
rapid diversification in a lineage
- 2.6 mya = start of Pleistocene
-Savanah hypothesis not = bipedality
Modified Savanah Hypothesis
-origin of HYPERmetadontia (big ass teeth)
-expansion of tool use
-big teeth for Paran., big brains for Homo
Reconstructing diet: Dental anatomy and morphology (teeth)
types of teeth, how many, what size, etc
Reconstructing diet: Mastication system (levers)
bones (maxillae and mandible), teeth, joints, neurovascular elements, and the muscles responsible for moving the mandible
Reconstructing Diet: Wear patterns (enamel microwear)
-more scratches= folivore
-more pits=frugivore
-lots of pits= brittle diet
-Limitation: “last supper phenomenon” (short term abrasions from weeks-months b4 death)