ABSTRACT
Biology was the domain for observers of nature right through the nineteenth century and Darwin’s theory of evolution was descriptive, not quantitative. Twentiethcentury scientists formalized Darwin’s theory with variables and equations. Ronald A. Fisher was primarily responsible for creating the scheme that we know today. He made the simplest possible assumptions: that genes were spread randomly through a population and evolved on their own, linkage playing an insignificant role. The ‘fitness of a gene’ was defined as its effect on the reproductive output of its bearer, averaged over all the gene combinations and all the micro-niche environments of a mating deme.
