E. Ya. Frisman

Learn More
We created and examined a mathematical model describing the size and genetic composition dynamics in a population with two age classes, where the survival of both zygotes and adult individuals is determined by one pleioptropic locus. Even under present limitations, as the outside effects of a complex multigenic system are reduced to the case of single(More)
The most striking and well known examples of changes in animal population dynamics are transitions between stable and cyclic phases in the lemming (Lemmus lemmus) populations all over southern Nor way [1] and in the red gray vole (Clethrionomys rufoca nus) populations in Finland [2]. The reverse situation can be also observed, when small fluctuations around(More)
152 Substantiation and development of classical matrix models of population dynamics [1–3] allows the importance of the age structure and developmental stages for maintenance and evolution of population cyclicity to be described in detail and analyzed [4–6]. Most studies on the evolution of the life cycle consider the formation of the age structure and its(More)
An evolutionary model of density-dependent selection in a two-age population is considered. The model is studied analytically and numerically; the parametric regions of its various dynamic behaviors are determined. An example is used to analyze how an evolutionary increase in the mean fitness results in a more complex population dynamics in a structured(More)
A mathematical model of the changes in the size and genetic diversity of a harvested, single-locus Mendelian population under the conditions of density-dependent selection is analyzed, with a special emphasis on the possibility of conserving or loosing polymorphism as a result of equilibrium harvesting. It is demonstrated that harvesting leads to changes in(More)
A model of density-dependent selection in a Mendelian single-locus population was analyzed in the case where the fitnesses of genotypic forms are exponential functions of the population size. Analytical and numerical studies of the model were performed for a diallelic locus, and parametric regions were established for different dynamic behaviors of the(More)
The process of trade withdrawal by commercial fishing or hunting is an essential component of the biological cycle in many intensely exploited populations of biological species. This process is often at least as important for population dynamics as the processes of natural mortality and reproduction. Although the trade withdrawal differs significantly from(More)
An investigation of the nature of dynamics of the population size and genetic structure is carried out for a homogeneous ecologically limited population influenced by density-dependent r-K selection in a single diallelic genetic locus. The detailed study of the results of basic types of natural selection is carried out with additional consideration of the(More)
The population dynamics of game animal and food fish species depend on many factors. In analysis of these factors, the hunting (fishery) pressure should be taken into account. Commercial game harvesting and natural mortality are significantly different in their effects on population dynamics. A common consequence of commercial harvesting is a transition(More)
A model simulating the growth and interaction of trees during their competition for light has been proposed and verified. Qualitative analysis of the model behavior at various values of parameters determining the tree growth rate has been performed. The model verification shows a sufficiently high accuracy of the model approximation of empirical tree growth(More)