EVOLUTION AS A SEARCH FOR ORGANIZATIONAL EQILIBRIUM.

Evolution of living systems is a succession of historical changes in their equilibrium states. In the individual life cycle, every such state is realized as an equilibrium of developmental system, i.e. as its adult organizational norm. A trigger for a switching the system to a search for a new equilibrium is the loss under critical conditions of effective regulation of normal development towards uniform final state. This is manifested by replacement of the adult norm by its individual deviations. Thus, the organizational change begins with its adult state, which is the first to undergo the disturbance under new conditions. Accordingly, with the transition of the organization to a new equilibrium, the remodeling of the developmental system extends in generations from the adult stage to earlier ones. These premises contrast with the accepted belief that evolutionary events begin with individual changes in the germ cell. The only substantiated alternative to the last approach is objectively presented by the concepts of Schmalhausen and Waddington, in which the change in systemic organization starts with stabilization of selected phenotypic variations generated by violation of the current adult norm. The evolutionary spreading of organizational changes towards the early developmental stages constitutes in this case a natural consequence of the stabilization process. This course of events is actually reflected in different ways in the many empirical generalizations that have grown in the scope of more traditional views. It may be predicted that this pattern will come to provide a basis for a revised understanding of the evolutionary process.