Study On Two Kinds Of Predator-prey Ecological Systems In Three-species

This paper is composed of two chapters: In Chapter 1, we consider following One-predator—Two-prey ecological system By using the techniques developed by Teng and Mehbuba , we obtain sufficient conditions for the permanent and extinction of the system .Furthermore, sufficient conditions are obtained for existence and uniqueness of uniformly global attractive and almost periodic solutions under the condition of almost periodic with help of the theories of almost periodic differential equation and by constructing proper Lyapuniv function. In Chapter 2, we investigate Holling-II type functional response periodic system with impulse: With the help of coincidence degree theory, easily verifiable criteria are established for the existence of positive periodic solutions of the system.