Test 1 Notes - Evolution of Populations, Agents of Change, etc...

Test 1 Notes - Evolution of Populations, Agents of Change, etc...

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Principles of Biology II - Leege Georgia Southern University Evolution of Populations: Agents of Change, Types of Selection III. What are the agents of change in populations? Three major factors alter allele frequencies and bring about most evolutionary change: Natural selection Genetic drift Gene flow Natural Selection Differential success in reproduction results in certain alleles being passed to the next generation in greater proportions Genetic Drift The smaller a sample, the greater the chance of deviation from a predicted result Genetic drift describes how allele frequencies fluctuate unpredictably from one generation to the next Genetic drift tends to reduce genetic variation through losses of alleles (Fig 23-7) The Bottleneck Effect The bottleneck effect is a sudden change in the environment that may drastically reduce the size of a population The resulting gene pool may no longer be reflective of the original population's gene pool (Fig. 23-8) Understanding the bottleneck effect can increase understanding of how human activity affects other species The Founder Effect The founder effect occurs when a few individuals become isolated from a larger
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This note was uploaded on 08/21/2008 for the course BIOL 2108 taught by Professor Leege,gleason during the Spring '08 term at Georgia Southern University .

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Test 1 Notes - Evolution of Populations, Agents of Change, etc...

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