The Roles of Heredity and Environment in Ontogenetic Adaptation

Abstract

The development of organisms involves simultaneous, opposed additive and subtractive processes. When the rates of such paired processes are equal, the organism has reached a dynamic steady state which is its final morphology. But such processes are physiological processes, and can be affected only by the physiological state of the organs in which they occur. If the environment exerts an effect on the physiological states of such organs, the steady (morphological) state will be shifted until it and its interactions with the environment serve to bring about the particular physiological state required for the equality of the additive and subtractive processes. If genes operate by determining reaction constants, for example, by determining the nature of the enzymes involved in developmental processes, they can determine only the physiological state in which a steady state will be reached, and the final morphological state will be that required to produce the genetically determined physiological state in the p...