BIOL2003 Lecture Notes - Lecture 2: If And Only If, Ecotype, Reproductive Isolation
14 Sep 2016
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Document Summary
The major mechanism of evolution is adaptation by natural selection. Iff traits of organisms have heritable variation and that variation affects the survival or repro- duction, then trait values will change across generations. simple, powerful, and inevitable. mutation = genetics. It is the genetic influence on phenotype that provides heritable variation, which is important when variation affects the survival or reproduction of an organism (darwins finches in beak size). The environment affects the development of phenotypes from genotypes. Three kinds of selection stabilizing, directional, and disruptive. Clines genetic differentiation in different places (side of a mountain) selection favours differ- ent traits in different places. Ecotypes when genetic variation is discrete instead of clines (dark and light mice; maintained by selection pressure to maintain the ecotype). In extreme conditions, ecotypes can cause spe- ciation.
