ANTHRO 7 Chapter Notes - Chapter 4: Genetic Drift, Speciation, Genetic Distance
Document Summary
Evol. forces: natural selection, mutation, and genetic drift. Microevolution: population change from natural selection and other evolutionary forces. Macroevolution: how new species and higher taxa are created. The biological species concept and ecological species concept. How new species, genera, families, and higher groupings come into existence. Defines a biological species as a group of organisms that interbreed in nature and are reproductively isolated. Reproductive isolation: members of a given group of organisms don"t mate successfully with organisms outside the group. Gene flow: movement of genetic material from within a population or from one population to another. Only one species of gorilla -> no breeding with any other kinds of animals. Emphasizes the role of natural selection in maintaining species boundaries. Even with gene flow species boundaries are maintained. Maintenance of coherence without gene flow between isolated subpopulations. Strictly asexual organisms support species maintenance w/o gene flow. Imagine an environment that only supports extreme beak size (large or small)
