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a trend in the theory of evolution according to which biological evolution is the result of environmental conditions, which bring about changes in organisms (the organisms themselves are only the passive material formed by these conditions). Adherents of ectogenesis argue that the environment, acting either directly or through the use or disuse of organs, causes adaptive changes that are later transmitted by heredity.
Ectogenesis is the opposite of autogenesis, which explains the evolution of organisms by the action of internal factors alone, for example, adaptive mutations or absolute expediency as the primary and immanent property of life. Neither ectogenesis nor autogenesis can account for all the observed phenomena of evolution, heredity, and variability. These mechanistic views are refuted by Darwinism, which affirms the dialectical unity of the external and internal factors of evolution. The British philosopher H. Spencer, the founder of mechano-Lamarckism, presented the most coherent exposition of the ideas of ectogenesis (seeNEO-LAMARCKISM).
A. S. SEVERTSOV