Chapter 4 - Chapter 4 Speciation and Phylogeny...

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Chapter 4; Speciation and Phylogeny Microevolution-consisting of mutation, genetic drift, natural selection Macroevolution-how new species and more general classifications come into existence Species-classification by which organisms cluster, usu. Quite distinct from other members of other species Biological Species Concept Defines species as a group of organisms that interbreed in nature and are reproductively isolated-only mate with members of same group Gene flow-the movement of genetic material with parts of a population or from one population to another-tends to maintain similarities among members of the same species Repro. Iso.-also prevents species from genetically blending No intermediates of chimps and gorillas because they are reproductively isolated, even if mating does occur, egg may not be fertilized and offspring may have decreased fitness or not survive Ecological Species Concept Emphasizes the role of natural selection in creating and maintaining species (species boundaries readily maintained even when there are substantial amounts of gene flow between species *existence of asexual reproduction, also shows that species can be maintained without gene flow- but not reproductively isolation; spatially isolated *Reproductive Iso. Usu championed The Origin of Species Usu. Evolution occurs too slow to observe entire process Allopatric Speciation-occurs when a population is divided by some type of environmental barrier(& different parts of population
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This note was uploaded on 08/26/2011 for the course ANTHRO 200 taught by Professor Gouzoulesandkonner during the Spring '11 term at Emory.

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Chapter 4 - Chapter 4 Speciation and Phylogeny...

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