Two Constrasting Interpretations of Fisher's Fundamental Theorem of Natural Selection

Greenland Institute of Natural Resources,Nuuk, GreenlandThe modern interpretation of Fisher’s fundamental theorem of naturalselection is based on Price (1972). Like Fisher, he described the theoremas a balance between a partial increase in fitness caused by naturalselection and a partial decline caused by the deterioration of theenvironment. But to obtain generality, Price sacrificed fitness as aphenotypic trait with a well-defined genetic and environmental compo-nent. This contrasts with a more recent phenotypic interpretation (Witting,2000a), where fitness is treated as a well-defined phenotypic character.The two interpretations are compared, with some discussion of the factthat the generality of the modern interpretation may be in conflict withFisher. As predicted by the phenotypic interpretation, Fisher described thefundamental theorem as if it applies only to an ecological vacuum wherethere are no interactions among individuals.