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Unformatted text preview: CHAPTER 23: The Evolution of Populations A species is a genetically distinct group of natural populations that share a common gene pool and are reproductively isolated from all others o Reproduction must result in fertile offspring Morphs- members of a species that look different, result from eating different food, different chemicals If all members have the same gene, then it is fixed Change in gene pool is microevolution Deme- smaller, local population Cline- a graded change in a character along a geographic axis Bergmens Rule- if you lok at closely related species, body sizes get bigger in cold climates o Surface area: body ratio Allans Rule- in similar species or subspecies, extremities get smaller in cold climates; less heat to lose through extremities Often times populations overlap Population- a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring As long as there is gene flow, species are not created Microevolution is caused by...
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This note was uploaded on 08/07/2009 for the course BY 124 taught by Professor Cusic during the Spring '08 term at University of Alabama at Birmingham.
- Spring '08