Phenotype

The phenotype is the manifestation of form that is created during the development or ontogeny of an organism. The development is instructed by the genotype and external environmental influences, and the interaction of the two.

The classical expression of phenotypic control is

P = G + E

However, the proper expression of phenotypic construction is

P = G + E + G*E

in order to account for interactive effects of environment on trait and/or fitness architecture.