Theodosius Dobzhansky: Meaning of Life on the Earth in the Light of Evolution

The article is devoted to the outstanding Ukrainian and American evolutionist, zoologist, geneticist Theodosius Dobzhansky (1900–1975). The life path and the main scientific achievements of the scientist are described, including genetic studies of the evolutionary process; he is one of the founders of the modern synthetic theory of evolution. T. Dobzhansky laid the foundations for the direction of experimental studies on evolution (studying the isolating mechanisms that prevent the crossing of individuals from different species). He demonstrated that the formation of a complex of isolating factors (geographical, ecological, ethological, reproductive, etc.) is an integral part of the speciation process, which provide in their totality the integrity of the gene pool of a new species. In his studies, the scientist combined Darwinism theories and the latest genetic data. The main issues considered by T. Dobzhansky included mutation as a source of genetic variability, role of chromosomal rearrangements, extent and types of variability in natural populations, natural selection, origin of species due to polyploidy, origin of species due to a constant development of isolating mechanisms, concept of species, etc. T. Dobzhansky began studying the pleiotropic effects of the genes. Subsequently, he brilliantly understood the significance of gene mutations in the evolutionary process. The approaches to the synthesis of genetics, evolutionary theory, anthropology, and sociology to understand the evolution of human nature are one more direction of the studies of T. Dobzhansky. He defended the concept of the diversity of human races at a scientific level. He strongly condemned pseudoscientific “theories” about the advantage of some races over the others, substantiated the meaninglessness of racism at a scientific level.