David BugenhagenAndrew Torano

Human Evolution

Dating for Dummies

• Radioisotopes are used to determine the age of a rock• C14 is used for younger samples of rocks, between the ages

of 1,000 and 100,000 years approximately• K40 is for anything older than 100,000 years• Both of these are used because they decay in very

predictable patterns and the half-life of each can be measured fairly accurately

• The half life of a rock or fossil is determined based on how long it takes the electrons of the radioisotope to decay

• The age of fossils is determined by carbon dating in much the same way as rocks, except carbon is used every time

We have monkey parts

• Opposable thumbs• Bipedal hips• Binocular vision eyes• Mobile arms and legs, shoulder and knee

joints can rotate many more directions than most mammals

• Modified skull for bipedal posture

Our REALLY BIG family tree

• See giant posters on wall

H.Neanderthal vs H.Sapien: The ShowDown

• A number of Australopithecus and Homo species coexisted in similar parts of Africa at the same time

• It is presumed that Homo Neanderthalensis and Homo sapiens coexisted in Europe, H. sapien is attributed with the extinction of H. Neanderthalensis

Looking for Dead Stuff

It has been hard to find fossils that clearly show the change of species from one to another.

Fossils rarely result when an animal dies because: •Decomposition is fast so soft body parts are rarely fossilized•Scavengers break up skeletons and chew up bones•The conditions have to be just right for fossilization to occurOnly a small fraction of all the fossils have been found, so there

are large gaps in the fossil record

Bigger is Better

A larger brain allows for:More complex toolsA mastery of fire for cooking, warmth, and

protection More advanced weaponsMore behavioral flexibility

As our brains have enlarged, we have eaten more meat, because easier to hunt.

Are we still Evolving?

• Genetic Evolution refers to genetic changes that have occurred over the evolution of hominids

• Cultural evolution is the changing of ideas held and actions and the transmission of these ideas through social learning from one generation to the next.

Fin