BIOL 1001 Lecture Notes - Lecture 20: Continental Drift, Genetic Drift, Sympatry
13 Jul 2017
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Lecture 20- speciation: isolation, allopatry and sympatry- textbook 98-102. Genetic isolation genetic divergence due to mutation ns genetic drift speciation results. When population moves to a new habitat, colonizes it and forms a new population. Dispersal followed by colonization isolate populations: reduces gene flow, genetic drift via founder effect and small population size cause diverging of new population from old, natural selection promotes divergence when new environment is different from original habitat, dispersal. When a physical barrier splits a population into subgroups that are physically isolated from one another. Glaciers were physical barriers and responsible for creation of modern species. Creating of panama as a continuous land mass was a vicariance. Thus physical isolation via dispersal or vicariance produces genetic isolation. When ns overcomes gene flow it can cause sympatric speciation. Eve(cid:374) though they"re (cid:374)ot isolated physically the gene pools are isolated by preferences for different habitats. Mate on haws and lay eggs on the fruit.
