Biology 1001A Lecture Notes - Lecture 14: Aposematism, Genetic Drift, Mutation
9 Apr 2016
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Lecture 14 - selecion versus other evoluionary forces. Blancing selection: posiive frequency-dependence eg. warning colouraion predator learns not to eat prey of certain colouraion frequency of alleles changes to the more common allele. Environment is always changing causes adaptaion to be one generaion behind environmental changes. Selecion is constraint by available geneic variaion. Selecion is not the only evoluionary force --> geneic drit and gene low can cause well adapted genes to disappear or bring in less adapted genes. Traits always come with tradeofs eg. delta32 allele less suscepible to hiv but more suscepible to west nile virus. Selecion --> adapion but not perfecion: limited by available geneic variaion, limited by dominance relaionships, plays catch-up ater environment changes, trade-ofs (compromise between compeing demands) Selecion is the only force that drives adapive evoluion but it"s not the only force that drives evoluion. Mutaions create new alleles: mutaion is not random but directed towards needs of the organism.
