Bio 201 F08 True lect 4v2r

Bio 201 F08 True lect 4v2r - Causes of Evolution small...

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small population non-random mating recurrent mutation migration selection Causes of Evolution These two processes involve introduction of new genetic variation {
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Origin of genetic variation Genetic change Mutation Recombination Sexual organisms: meiosis Bacteria: DNA uptake from environment and/or exchange of species-specific plasmids (circular DNAs) Gene Flow (migration)
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small (effective) population size non-random mating recurrent mutation migration selection Causes of Evolution
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EFFECTIVE population size • Refers to the number of individuals who successfully reproduce • This number may be substantially smaller than the total number of individuals in the population – In a sexually reproducing species, there may be 50% males and 50% females in the population • BUT that does not mean that every individual reproduces
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Genetic Drift Fig 23.7
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Genetic Drift Fig 23.7
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Genetic Drift Fig 23.7
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Genetic Drift: Bottleneck Effect Fig 23.8 Increase in frequency of blue allele and loss of yellow allele occur by chance.
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Bottleneck Effect
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Non-random mating: Inbreeding AA Aa aa e.g. "selfing" in plants AA 100% aa 100% Aa 50% 25% 25% Result: excess of homozygotes (See textbook Fig. 22.11 for example of how some plants avoid inbreeding with flower structures)
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small population non-random mating recurrent mutation migration selection Causes for Evolution
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Adaptation
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This note was uploaded on 04/14/2009 for the course BIO 201 taught by Professor True during the Fall '08 term at SUNY Stony Brook.

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Bio 201 F08 True lect 4v2r - Causes of Evolution small...

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