Phenotypic evolution under Fisher's Fundamental Theorem of Natural Selection.

Lande's (1982) equations for phenotypic evolution are derived as a linearized version of Fisher's Fundamental Theorem of Natural Selection. In this derivation the genetic covariance matrix is not necessarily a fixed object and is likely to alter as directional selection proceeds. Under stabilizing or equilibrium selection, the mean phenotypes take on values identical to those which would be predicted by an "optimization of fitness in the face of tradeoffs" approach. It is argued that optimization is a more powerful way to understand equilibrium or stabilizing selection.