The Model of Fitness in a Heterogeneous Environment on Reaction Norms

The understanding of genetic mechanisms of natural selection to a large extent became possible as a result of modelling research carried out in the fields of evolutionary and population genetics. However, genetic models cannot be considered exhaustive in the description of natural selection because a phenotype of individual, environment and fitness remains beyond their framework. Consequently, the value of fitness is not derived from the algorithmic model but arbitrarily assigned by a researcher to genotypes in their genetic formula. This work proposes a model of genotype fitness in heterogeneous environments on reaction norms in connection with the genetic structure of the population. Two equations represent the model. The first is an incomplete second order polynomial that describes the dependence of fitness on the phenotype of an adaptive trait and environmental conditions. The second is a linear equation of the reaction norm of the adaptive trait that determines its phenotype in specific environmental conditions. According to the model algorithms, rating of fitness in the population, and, consequently, their probability of selection, is determined by phenotype optimality and their norm of reaction in certain environmental conditions.