[Fitness, carrying capacity and competition in an ecosystem].

In this paper a model is introduced in which fitness, carrying capacity and competition are considered. Thereby as well genetic as ecological parameters were assumed to become active. It results from the investigations that: 1. Competition may compensate the influence of genotypic fitness. 2. The carrying capacity has a more important influence on the construction of a population than the genotypic fitness. 3. As well competition as carrying capacity are parameters which do influence not only the size of the populations but also the genotypic construction of the populations. Therefore for a description of populations it is necessary to take into account a polyfactorial system with genotypic fitness, carrying capacity and competition. The model proposed has been compared with those described in the literature. The importance of population fitness and by it the genetic load has been discussed considering ecological parameters such as competition and carrying capacity.