Phenotypic variation

Phenotypic variation

Phenotypic variation is a fundamental prerequisite for evolution by natural selection. Not all phenotypic variation is caused by underlying heritable genetic variation. This is because the organization of living things is 'plastic', as Darwin emphasized, or 'readily capable of change.' It is the living organism as a whole that interacts with the environment and so contributes (or not) to the next generation. Thus, natural selection affects the genetic structure of a population indirectly via the contribution of phenotypes. Without phenotypic variation, there would be no evolution by natural selection.