Neutralistyczna i syntetyczna teoria ewolucji

Abstrakt

In the article the author undertakes a scrutiny of two different kinds of explication of evolutionary processes. One of them is explication with the use of natural selection and favorable mutations as the main factors of evolutionary changes. Another attempt at explication of those changes is the one presented by the author of neutralist theory, Motoo Kimura. It accepts accidental genetic drift and accumulation of neutral mutations as the basic mechanisms of evolution. Numerous researchers say that this is non-Darwinian theory of evolution. However, it should be noted that natural selection and the possibility of occurrence of positive mutations are not altogether eliminated from the presented picture of evolution. In the case of changes in environmental conditions the accumulated neutral changes may prove to be adaptive ones and then they will be selected by natural selection. The neutralist theory does not seem to be involved in the difficulties that the synthetic theory of evolution encounters. Such problems are meant here as the costs of the action of the natural selection, the speed of the evolution that seems to be too low for such evolutionary changes that we can see now to occur (assuming given costs of natural selection) and corpuscular polymorphism that occurs rather commonly. Also criticism of neutralist explication is presented as well as a possibility of harmonizing these two kinds of explication.