Evolutionary Implications of Phenotypic Plasticity in Plants

Abstract

This chapter considers the nature, role, and evolutionary implications of phenotypic plasticity as an adaptive property in plants. Plasticity is here defined as variation in phenotypic expression of a genotype that occurs in response to particular environmental conditions and which enhances the capacity of the individual to survive and reproduce under those conditions. A distinction is made [following Dobzhansky (1969) and Harper (1982)] between adaptive, defined as conferring a benefit on the organism with regard to its present relationship with its environment, and adapted, which describes a character that is thought to be the product of natural selection over previous generations—i.e., which was adaptive in the past and was therefore fixed by natural selection. “Adapted” refers to the causal origin of the character in evolutionary history; “adaptive” says nothing about the origin of the trait, but merely describes its present value in a given environment.