Wk-11 Human Evolution

Evolution - natural selection peppered moth Species are v? Increase in survival / reproduction in some species due to favourable environment This results in increase in offspring with the f? v? Least favourable traits p?

Gene mutations: Create huge v? Mutations occur from errors in copying ? Alters g? and may create novel a? New a? may result in changed p?

Phylogenetic tree = ? Demonstrates the evolutionary relationship between species descending from a c? a?

Gene flow: migration Is the transfer of 1 gene variant from 1 population to another. Predominantly occurs from migration ?/? population This results in h? a combination of genes from 2/more distinct populations.

Genetic drift- small populations Random changes in gene variant frequency A random change in small populations > leads to F? Effect Results in loss of some g- v- in future generations

Founder effect: reduced variation Loss of genetic variation in a new small population Not all gene variants are present Original population > possible founder populations Seen in small culturally i? groups Small populations and in-? increase probability inheriting diseased a?

Human evolution : hom? Darwin ? ? Theory Hom? (similarities between organisms) Mammals have anatomical h? Comparative genomics (same number of genes –,000 and genome size, - billion) Human and mouse genes -5% similar Human DNA and chimpanzee DNA -% different

Human evolution: Humans derived from h? (Primate Evolution) What are the 4 major events in evolution? 1. T? Trees> land 2. B? All 4’s > 2 legs 3. E? Increase brain capacity 4. C? Society more complex

Bipedalism (Lucy) 1st change differentiated apes and humans other mammals Gradual change in p? and limbs - ? Million years ago (Lucy) Reduced c? ability Increase w? and r? motions

Hominids: 6 evolutionary stages • Austral-? • Homo? • Homo er? Homo eg? • Archaic homo s? • Homo s? Nean? • H? S?

• Australopithecines 4- ?.6 million years ago 1- ?.5 m tall Capable of bi? (Lucy) • Homo habilis ?.3 - 1.4 million years ago Increase ? Size 1.2 - 1.6 m tall

• Homo erectus / homo ergaster 1.8 million ya to 1-0 thousand years ago 1.6 - 1.? m tall Increase ? size continues Use ? Tools Modern human p? Migration out of ?

4. Archaic Homo sapiens 300 to ?00 thousand ya Large brain Decrease height/size Increase ? and culture structure

• Homo neanderthalensis 130 to ?0 thousand ya More robust , similar to modern ? • Homo sapiens ?00,00 ya to ? Increase brain Extensive society and culture structure

Migration theories: • Out of Africa • Multi regional Genetic evidence supports ? Second wave of modern humans 150 to ?00 thousand ya replaced previous migrants