Bio 1B: Lec 9: Human evolution as a capstone

What appears earlier: bipedality, very large brains, or complex tools?

Bipedality came first before everything

Briefly summarize history of homonids

Early homonids: Sahel, Orror, and Ardi

Australopithecus

Paranthropus

Homos (erect then sapiens)

Where did moderns human originate?

Originated in Africa, then migrated to other places

What migration model fits evidence of the past?

Braided network: African origin, followed by migration, contact, and a little gene flow with other lineages

Homo sapiens were sympatric with Neanderthals in Europe and Denisovans in Asia

Summarize our adaptations

First, bipedality, got long legs and head/trunk stabilization, many sweat glands and reduced fur for long-distance movement and heat loss during activity

Then, large brains lead to tools, social cognition, ecological problem-solving, leads to long childhood and increased parental investment, so now have cooperative care, food sharing, alloparenting, culture, and teaching

Evolutionary mismatch

A trait can be useful in one environment and harmful when environment changes faster than biology (bodies like sugar for fuel for running a lot, but now we don’t run at all)