Synthetic Theory of Evolution was created by combining the 20-ies of the ecology, genetics and Darwinism.Today it is considered the most complete and developed quite complete.Synthetic theory of evolution embodied the classical population genetics and Darwinism.
the first to introduce a genetic approach was Chetverikov, Sergei Sergeyevich.In 1926, he published an article in which the evolution of life (in some aspects) viewed from the perspective of genetics.In his work Chetverikov brought several provisions.As an example, they were taken natural populations of fruit flies.Thus, the scientists found:
- mutations in nature are constant.
- Recessive changes can persist indefinitely in the heterozygous state.
- With the passage of time (aging) as accumulate mutations signs form while loosened.
- main factors of differentiation are intraspecific genetic variation and isolation.
- Panmixia (free interbreeding) leads to polymorphism and selection - a monomorphism of the species.
theory presented Chetverikov, it indicates that the accumulation of means of random mutations contribute to adaptive directional, flow patterns during development.Scientific developments continued Russian geneticists such as Romashov, Timofeev Resovskii Vavilov, Dubinin and others.The works of these and other workers formed a position on which the synthetic theory of evolution.
In the 30th year of Wright Holdeymsa, Fischer laid the foundation for the development of the doctrine in the West.
One of the first works, which was outlined in the synthetic theory of evolution in nature, Dobzhansky was a monograph on the origin of species and genetics.The paper puts more emphasis on the study of genetic mechanisms of formation of the population under the influence of various factors.The factors, in particular, the genetic variability, fluctuation of the number of individuals in different populations, migration.Greatly influenced the evolution and causes of, and reproductive isolation is formed in the form of new forms.
is an outstanding contribution to the development of doctrine Schmalhausen.In accordance with the creative union of embryology, evolutionary theory, paleontology, morphology and genetics, scientists have conducted in-depth research relations phylogeny and ontogeny, studied the major trends in the evolution, and has also developed a number of fundamental provisions of the modern theory.
Among the fundamental research work occupies an important position Huxley's "Evolution. The modern synthesis."Of great importance were also the study of forms and rates of development taken by Simpson.
Synthetic theory is based on eleven major postulates.They concisely formulated Vorontsov.
- mutations, as small discrete changes in heredity, considered an evolutionary material that is random.
- importantly, to some extent, even the only driving force behind development is considered to be a natural selection, which is based on a selection of small and random mutations.
- smallest unit is considered to be an evolving population.
- Development has gradation (gradually) and continuous nature.
- type includes many subordinate and yet distinguishable (morphologically, genetically and physiologically), but not reproductively isolated units.
- Evolution suggests signs of divergence.
- flow of genes (alleles exchange) is allowed only within a species.In this regard, one (kind) is considered complete and genetically closed system.
- View Properties not apply to the forms that reproduce asexually and parthenogenesis.
- Macroevolution occurs through microevolution.
- Real taxon has monofiliticheskoe origin (refers to one ancestral form).
- Evolution is the process unpredictable, has a non-directional nature of the ultimate goal.
