  However, as Beatty has pointed out, it was quite common until fairly recently to characterize natural selection in such a way as to make it almost indistinguishable from random drift (cf. Lennox 1992, Lennox and Wilson 1994).  Numerous accounts of fitness characterized the fitness of a genotype as defined by its relative contribution to the gene pool of future generations—the genotype contributing the larger percentage being the fitter.  But of course that could easily be the result of a ‘random’—non-fitness biased—sampling process; which organisms would be declared ‘fitter’ by this method might have nothing to do with natural selection. In order to provide a proper characterization of the role of chance in evolutionary change, then, it is critical to provide a more robust and sophisticated account of fitness. (For  further information, see the entry on    fitness.)   This, in turn, requires that we discuss the conceptual network that includes the notions of adaptation and natural selection, to which we will turn shortly.  