A critique of the epigenetic theory of evolution
Institute of Animal Systematics and Ecology, RAS, Siberian Division
630091 Novosibirsk, ul. Frunze, 11
e-mail: mammal@eco.nsc.ru
Comparison of fundamentals of the synthetic (STE) and the epigenetic (ETE) theories of evolution indicates that they presume different approaches to description of evolutionary process, STE presuming its mechanistic (reductional) description and EТЕ presuming its organismic (holistic) description. The following system of postulates can be suggested for ETE: evolutionary changes begin at the phenotype level, the species represents an elementary evolutionary unit, changes in developmental (ontogenetic) system represents an elementary evolutionary phenomenon, evolution is a non-uniform process. A balanced system of organization is very stable, as it is presumed by A.P. Rasnitsyn's metaphor of adaptive compromise, so emergence of a new taxon is possible due to destabilization stage under reduced competitive condition. Emergence of an evolutionary novelty is non-adaptive because of retarding effect of the adaptive compromise. An elementary evolutionary cycle includes the following phases: 1) destabilization, i.e. appearance of morphoses resulting from changes of environmental conditions (inadaptive phase), 2) stabilization via genetic assimilation of one of the morphoses (euadaptive phase), 3) stasis. However, genetic assimilation is not obligatory precondition. The notions of inadaptation and euadaptation differ from their original meanings of V.O. Kovalevsky. Empirical data provided by D.L. Grodnitsky do not support a postulated taxogenetic process, i.e. transition from one to another phenotypic stages, so applications of these notions to description of the phases of elementary evolutionary cycle are incorrect. More profound taxon concept as well as methodology of empirical interpretations are needed for further development of ETE.
