The cost of changing

Abstract

So far the discussion has been almost entirely confined to problems of relative fitness, Although fitness has been defined in a way which could, in principle, be absolute the concept has always been used in a relative sense. One genotype maybe fitter than another, and so increase in frequency, whether the population in which it occurs remains stable, increases in numbers or is in the process of crashing to extinction. It is now necessary to inject more ecological reality, In practice all selection involves either differential mortality or differential output, so that no matter by how little, polymorphism reduces the potential of the population for increase. The extent to which this sets limits on the rate of evolution is another current preoccupation of population genetics.