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MATSUDA, R. 1982. The evolutionary process in talitrid amphipods and salamanders in changing environments, with a discussion of "genetic assimilation" and some other evolutionary concepts. Can. J . Zool. 60: 733-749. The evolutionary process of talitrid amphipods and salamanders involving neoteny in changing environments consists of the aspect of environmental induction of structural changes as a result of altered activity of the preexisting endocrine mechanism and the aspect of natural selection which results in canalization of development and genetic assimilation of the modified (neotenous) phenotype. The prevalence of genetic assimilation is discussed, along with the cases where traditional neo-Darwinism applies. By taking the fact of environment-hormonal induction of gene regulation and the aspect of natural selection into account, mechanisms of macroevolution, ,preadaptation, plasticity in morphogenesis, and a mode of speciation are discussed. A historical review is presented concerning the theories (the Baldwin effect and Weismann's theory) related to genetic assimilation and neo-Darwinism.MATSUDA, R. 1982. The evolutionary process in talitrid amphipods and salamanders in changing environments, with a discussion of "genetic assimilation" and some other evolutionary concepts. Can. J. Zool. 60: 733-749. Le processus Cvolutif qui implique la nCotCnie dans des milieux changeants chez les amphipodes talitridCs et chez les salamandres rel&ve d'une part de l'induction Ccologique des changements structuraux qui rksultent de I'activitC modifiCe du mkcanisme endocrinien prkexistant et, d'autre part, de la sClection naturelle qui entraine la canalisation du dCveloppement et l'assimilation gCnCtique du phCnotype modifiC (nCotCnique). La discussion porte sur la prkdominance de l'assimilation gCnCtique ainsi que sur l'application, en certains cas, du nCodarwinisme traditionnel. Sont analysis aussi les mCcanismes de macr&volution, la prkadaptation, la plasticit6 au cours de la morphogen&se et le mode de spkciation, a la lumi&re de l'induction Ccologique et hormonale de la rkgulation gCnCtique et a la lumi&re aussi du phCnom&ne de sClection naturelle. Une revue historique des thCories (effet Baldwin et thCorie de Weismann) relikes a l'assimilation gCnCtique et au nCodarwinisme est prCsentCe Cgalement . [Traduit par le journal]No organism can grow and develop without environmental stimuli. However, integration of this most fundamental biological principle into the study of evolution has been almost a taboo for a long time, and for some historical reasons (p. 746). Nevertheless, I shall attempt below to examine closely, based on the available evidence, the significance of the morphogenetic effect of environmental factors in evolution, while attempting to see how environments have acted also as selective agents during the same evolutionary process.To see the environmental effect clearly, I have chosen talitrid amphipods which have changed their habitat from sea to land during phylogeny, and salamanders which normally change ...