Australopithecine Adaptations: The Big Picture
Monday, April 15, 2013
•From ~7 to 3 MYA, only a slight trend toward increased brain size
•Sahelanth: 320 cc
•Au. Afrarensis: 430 cc
•Australopiths have ape-sized brain and cranium that is porgnathic with large, robust
•Tougher food items?
•More resistance to wear? (Bipedal connection)
•Ancestral Condition (Primitive e.g., chimps, Dryopithecus?)
o Ripe fruit
o Thinner enamel
•Most Australopiths (Derived)
o Tougher, harder, and/or more abrasive food items (e.g., nuts, tubers?)
o Thicker enamel
o Larger cheek teeth
•Get smaller through time
•Lose honing faucet
1. Reduced competition?
2. New diet?
1. Tool use?
Remember: Common chimps use tools
LCA of Pan and Australopithecus probably had the capacity, but earliest stone tool use.
•Habitually bipedal when on ground, but retain climbing adaptations
A. Why become bipedal anyway?
•Bipedalism is a silly way to get around… slow, back problems, broken hips, etc.
o Knuckle walking a good compromise for retaining arboreal features, but is
o Bipedal walking is hi