| As the pollution of our environment is more serious day by day, the survival environ-ment of biological is deteriorating. There is widespread concern that the impact of a toxic state of the population living. Research on changes of population's survival condition in a polluted environment becomes a hot topic in mathematical ecology. For all we know, pollution and capture are two important factors that affect the survival and development of population. With the increasing population living space is more and more narrow, population of environmental toxins from the death of concentration of population and toxins through the effects of food chain also should not be ignored. In this paper, we discuss the survival analysis for the unequal concentration of toxicant for the predator-pray system in a polluted environment. Considering the development of population and the influence of people's capture behavior, given the threshold of persistence and extinction for the population. Namely, gives the threshold of a change in the population development trerd. Besides, considering the influence of pollution on the population, it can be estimated how we should control safe contamination in order to maintain the balance of ecosystem. It also can be referenced in controlling the stability of ecosystem. There are four chapters in this paper:The first chapter, firstly, we introduce the development course of ecological mathematics and ecotoxicology briefly. The background and history of current research situation about the related work are introduced. Secondly, the research process further the deficiencies and solve the problems in this area are pointed out. Finally, we introduce the major work of this presentation.The second chapter, we introduce some preliminaries throughout this paper.The third chapter, we study on the threshold of persistence and extinction for two-dimensional Volterra predator-pray system with the unequal concentration of toxicant. In environ-mental capacity of smaller conditions, takes into account not only of population factors are full consideration of environment of population death, but also the influence of toxins concentration. Through the calculation, we get the sufficient conditions of persistence and extinction of species. Obtaining the following results:The system continue to survive if two populations are survive and the entire system extinction if two populations have an extinction.The forth chapter, in the unequal concentration of toxicant, we investigate the living state of three species model based on ratio-dependent HollingⅡ. In environmental capacity of smaller conditions, the functional reaction function combine with ratio-dependent. Fully 体内'素浓度不相同的捕食一被捕食系统持续生存与绝灭的阈值研究considered dependence on environmental pollution for people's capture,population inbetween the internal transfer,death and toxins into the environment and toxins through thefood chain to influent the population.The relationship between the population is describedemphasizly.The model of three species is established,which has one prey and two kindscompeted predator. By means of comparison theorem and analytic method,giving thethreshold of three species system based on ratio-dependent HollingⅡwith capture in apolluted environment.Keywords:Environment pollution;Persistence；Extinction;Ratio-dependent... |
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