Bio; Lecture 11; Natural Selection

Bio; Lecture 11; Natural Selection - Principles of Biology...

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Principles of Biology 2 BIO U103 2/1/07 Natural Selection o Acts on phenotypes, but results in change of genotype frequency within a population o Acts on the individual—differential reproductive success amongst an individual o Evidence of evolution is on the population magnitude however o Types of natural selection patterns Stabilizing selection : stabilizes a phenotype Acts against the extremes Directional selection : shift from one extreme to the other Disruptive selection : results from interaction of two or more opposing selecting pressures, and breaks up a population o Stabilizing selection This type of selection acts against the extreme phenotypes The variation of the particular trait in the population is reduced From generation to generation, the range of distribution goes from wide to narrow Variation of a particular trait in the population The mean, however, remains the same. Sparrow wing span
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This note was uploaded on 05/26/2008 for the course BIO 103 taught by Professor Potts-santone during the Spring '07 term at Northeastern.

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Bio; Lecture 11; Natural Selection - Principles of Biology...

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