Lecture 2: Evolution and Natural Selection Book: Chapter 2
Cuvier: father of modern paleontology Comparative biology: linked morphologies of fossils to living organisms Did not believe in evolution~ species are stable through time BUT- they could go extinct Catastrophism
Lamarkian Evolution Evolution by the inheritance of traits that are ʻemphasizedʼ during an organisms lifetime. If a giraffe stretches itʼs neck, itʼs descendants will have longer necks. Use & Disuse: individuals lose characteristics they donʼt use, and emphasize characteristics that they DO use No extinction
Evolution by Natural Selection Charles Darwin: main body of the theory “On the Origin of Species” Alfred Russel Wallace: codiscovered theory based on biogeographical observations Requires: Inheritance, Variation, and a Selective ʻForceʼ Variants do not have equal reproductive success Fecundity: offspring production Survivorship: not dying These work in parallel. You need both to be ʻfitʼ Fitness The fitness of an organism is based on a relative scale. You donʼt need to be ʻabsolutely fit- you just need to be more fit than they other guy/gal Evolution= the change in frequency of genotypes over time.
What defines a ʻsuccessfulʼ organism?
Natural Selection vs. Evolution Natural selection works on the level of individuals Evolution works on the level of populations
Types of Selection Direction, Stabilizing, Disruptive
Speciation
Evidence for Evolution: