the origin, development, and transformation of adaptations during the process of evolution of the organic world. Darwin’s discovery of the mechanism of organic evolution has shown that in essence all evolution is adaptogenetic: any feature of organization is adaptive. The extremities of terrestrial vertebrates have the most diverse structure because of adaptation to running, burrowing, swimming, or flight, but the basis of the structure of the extremities is the same—a complex lever. Adaptogenesis is linked with the basic features of living matter: variability and heredity. New adaptations appear as a result of the survival of the organisms most adapted to the given conditions. During the evolution of a group, some adaptations lose their value and disappear, while others spread and become characteristic of groups of organisms. Two principal ways of adaptive transformations of groups are distinguished: an increase (or other drastic change) in degree of organization (aromorphosis, arogenesis, anagenesis) and development without a change in the degree of organization (idioadaptation, cladogenesis, adaptive radiation). A highly important characteristic of the adaptogenesis of a group is the periodic alternation of these principal pathways. Sometimes, adaptogenesis is defined more narrowly as the origin of adaptations, while the process of development and succession of adaptations is called adaptomorphosis.
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Takhtadzhian, A. L. Sistema i filogeniia tsvetkovykh rastenii. Moscow-Leningrad, 1966.
Severtsov, A. N. Glavnye napravleniia evoliutsionnogo protsessa, 3rd ed. Moscow, 1967.
A. V. IABLOKOV