title: A quantitative model of the Simpson-Baldwin Effect.
abstract: G. G. Simpson was the first to explain the Baldwin Effect completely in terms of the theory of natural selection. A genetic version of a seemingly non-hereditary adaptation may arise when natural selection acts on the likelihood of having an adaptive trait not just on the trait itself. We present a quantitative model of the Simpson-Baldwin Effect. Organisms in the model have mutable ranges of phenotypic plasticity. The distribution of phenotypes in a population depends largely on the extent of environmental stochasticity. When the environment undergoes intermediate rates of fluctuation, the Simpson-Baldwin effect arises through the interaction of natural selection and mutation on norms of reaction. In a highly volatile environment, organisms benefit from plasticity, and consequently do not experience a Simpson-Baldwin channeling of phenotypic possibility.
authors.affiliation: Department of Biological Sciences, Stanford University, CA 94305, USA. ancel@charles.stanford.edu
authors.forename: L W
authors.initials: LW
authors.lastname: Ancel
mesh_terms: D000818:Animals; D004777:Environment; D019143:Evolution, Molecular; D006801:Humans; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D011157:Population Dynamics; D012641:Selection, Genetic