Epigenetic processes, when natura non facit saltum becomes a myth, and alternative ontogenies a mechanism of evolution

Abstract

Populations of phenotypes which form a species occur only at various stages of individual ontogenies. A single cell, the egg, cannot be in the same stabilized state as a differentiated multicellular embryo or reproducing adult. The entire ontogeny must, therefore, consist of a sequence of stabilized states. Ontogeny of a phenotype cannot progress gradually but is a saltatory homeorhetic system, proceeding via natural thresholds from one self-organized state to the next, hierarchically ever more complex and specialized. A choice between two stabilities on one level in this organized system of change may result in bifurcations into more indirect and more direct ontogenies, maintenance and dispersal phenotypes, generalists and specialists, or simply as I prefer to call it all - altricial and precocial forms. Like the wave-particle duality in physics, life processes use bifurcations to create both novelties and alternative answers, to be ready when required at any interval of ontogeny and evolution. The bifurcations at various times of epigenesis, inter alia, sum-up into two different sequences of ontogeny, one more generalized, the other more specialized - the altricial ⇄ precocial homeorhetic states. These states are channelized via bifurcations into different self-organized and stabilized intervals, until change or extinction become inevitable as a result of lost variation during the constant tendency to specialize. The ability to maintain altricial and precocial forms in every generation lineage makes it possible at any time to have two answers prepared for any future unknown environment. If certain epigenetic changes persist for generations in a suitable environment and become isolated, a new evolutionary unit (e.g., species) may be assimilated. These epigenetic interactions of the internal and external environments of a developing individual are the primary mechanisms responsible for the maintenance of the initial taxa as well as for the formation of every new taxon.