The Human Chimp

Aug 22nd

How Similar are Chimps and Humans?

• Implications

• What are the similarities?

Molecular Clocks

• Used to measure genetic distances and to date times of evolutionary divergence

• How it works:– Based on fossil evidence, lions and tigers diverged

5 mya and molecules differ by 1%– If we then took 2 other species and found they

differed by 3%, the molecular clock would say they diverged 15 mya

DNA• The best molecule for use with molecular

clocks

• To measure the change in DNA structure:– Mix DNA from 2 species– Measure how many degrees of temperature the

melting point of the mixed DNA is reduced below the melting point of pure DNA from a single species

– A melting point lowered by 1°C means the DNAs of the 2 species differ by roughly 1%

Family Tree of the Higher Primates

Man the Hunter

• Unclear whether early Homo sapiens were hunters or scavengers

• Big-game hunting led to – The development of language and bigger brains?– Concealed ovulation?

The Human Family Tree

The Great Leap Forward

• When modern humans replaced Neanderthals

• 3 changes launched us in the direction of modern humans– 4 mya – upright posture– 3 mya – Australopithecus robustus and A.

africanus– 2.5 mya – tool use

• 40,000 years ago in Europe

• Arrival of anatomically modern people - Cro-Magnons

• Art, musical instruments, lamps, and trade

• Needles, rope, fish hooks, mortar and pestles, harpoons, darts, bows and arrows

The Great Leap Forward

Examples of Aurignacian Culture art