BIOL3044 Lecture Notes - Lecture 17: Heritability, Mutation Rate, Mutation
Document Summary
Fisher offered one of the first mathematical definitions of fitness: the idea that fitness is the lifetime reproductive success of a particular genotype, he worked it out from lifetables of age-specific survival and fecundity. Fisher offered the concept of genetic variance. It was the variance among genotype means: the genetic variance was the sum of the variance contributed by the genes affecting fitness. Fisher proved the mathematical inevitability of adaptation. The rate of increase in fitness in a population (for a particular set of ecological circumstances) would be equal to the additive genetic variance in fitness. If there were heritable variance for fitness, then fitness would increase and the population would become better adapted. That if traits are related to fitness, then heritable variation in the traits would be heritable variation in fitness. If traits are related to fitness, their heritable variation would fuel evolutionary change. As a result, selection will remove heritable variation in fitness.
