19_Mechanisms_of_Evolution_Nat_Sel_Feb_15_

Comprehension survival of the alleles that increase

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Unformatted text preview: hy an adapta+on is not universally good; and adapta+ons always represent compromises (how an organism’s phenotype always represents a compromise between the adap+ve values of mul+ple traits. [Comprehension] Survival of the alleles that increase fitness •  Alleles that increase an individual’s fitness ‘survive’ in the popula+on more than alleles that decrease individual’s fitness •  Fitness  measure of rela%ve amount of reproduc+on of an individual with a par+cular phenotype, as compared with reproduc+ve output of individuals with alterna+ve phenotypes •  E.g., 2 fruit flies – different alleles for trait • 1  version of gene allows survival for long +me w/out food • 1  version of gene allows survival for short +me w/out food Which fly has the greater fitness? 88 Survival of the alleles that increase fitness 1. Fitness is a rela+ve measure 2. Fitness depends on the specific environment in which the organism lives. •  E.g., an+bio+c ­resistant bacteria Rela+ve fitness – fitness of 1 allele (or combina...
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