Psychology 3228 Lecture 3: Psych Chapter 3
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Evidence for natural selection: fossil record, homologies, universal genetic code, artificial selection, direct observations. Same ancestral trait and are the same embryologically. Not homologous octopus, grass hopper, sea star. Even with different ancestors adaptations that help survive and reproduce they produce similar features. Reason dolphins and sharks look similar is because that body type survives well in water these are analogous traits not homologous traits. Natural selection in the wild - book: by (cid:883)(cid:891)(cid:890)(cid:882)(cid:495)s hundreds of direct measurements of natural selection in the wild. Shaded area is part of the trait that dies off. Directional: one moving directions the individuals that don(cid:495)t survive and reproduce shift the mean neck of giraffe getting longer. Not good to be too tall not good to be too short, the ones that survive are average. As shown in picture the extreme forms are less likely to reproduce you have natural selection but not evolution, everyone becomes closer to the mean.