CAS AN 102 Lecture Notes - Theodosius Dobzhansky, Heritability
14 Mar 2014
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1. reproductive competition among individuals: phenotypic variation that affects reproduction, phenotypic variation is heritable evolution changes in gene frequencies over time genotype affects phenotype, many once accepted the idea of blending inheritance tall x short = medium, easy to understand how it works natural selection accounts for the intermediate forms traits are mostly polygenic natural selection is bad at explaining how genetic variation is maintained for million of years only phenotype blends, genes remain one or the other but sometimes alleles do. Get eliminated: mutations are the ultimate source of genetic variation, mate guarding, males prevent other males from mating thereby improving male reproductive success, males who mate guard experience cost because guarding a female prevents him from mating with other females, only occurs is huge numbers when the number of females is low compared to the males, usually 1:1 or 1:2.
