Ecological Mechanisms for the Maintenance of the Genetic Heterogeneity of a Population
When the genetic heterogeneity of a population takes the character of an expressed polymorphism, its biological significance becomes obvious. It consists in the great range of conditions that the population as a whole can utilize for the maintenance of optimal numbers. The data cited and discussed in Chapters I and III show that modern ecology is still far from an understanding of the role of polymorphism in the life of animals. The degree of adaptation of different genotypes to different environmental conditions attains a degree of specificity about which we can only guess at the present time. Some experimental data address this point. They indicate that not only the representatives of different phases, but also the different genotypes, occupy a different position in the system “population—environment,” since they occupy different ecological subniches (Lewontin, 1955). Convincing indirect data support the ideas developed by Lewontin. It was found that populations distinguished by expressed chromosomal polymorphisnis are also distinguished by a broader distribution and greater diversity in the biotopes occupied (Cunha and Dobzhansky, 1954; Cunha et al., 1959). Furthermore, populations with an impoverished gene pool are characteristically limited in the number of ecological niches occupied.
KeywordsWild Boar Sexual Maturity Genetic Heterogeneity Young Male Young Female
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