Theoretical study of a role of evolution of intraspecific interactions in origination and maintenance of biodiversity

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The studies of this project can be classified into two categories, macro-and microscopic studies about biodiversity. The first macroscopic study is a theoretical study of effect of defense evolution and optimal diet choice on population dynamics in one predator-two prey system. In this study, it was revealed that evolutionary and behavioral changes of the concerned species facilitate both stability of the system and coexistence of species. The second macroscopic study is an analysis of optimal phenology of annual plants under grazing pressure. This study indicated that the growth schedule of plant possibly varies, responding to interactions with herbivore animals. This provides basic information to understand properties of plant-herbivore interactions that are fundamental for the species diversity.On the other hand, the first study from the microscopic viewpoint is a study of gene transfer rate from mitochondria to nuclear. Mitochondria were originally free-living bacteria, which subse … More quently became an intracellular symbiont of eukaryote. I analyzed an evolutionary process, during which mitochondria have achieved tight mutualism with their hosts. This study included various suggestions for studies of establishments of mutualistic relationships that are essential component of biodiversity. The second microscopic study is an analysis of persistence condition of symmetric social hybridogenesis in ants. In this study, we analyzed genetic dynamics of alleles that controlled the caste determination in a certain ant species. The analysis clarified conditions for polymorphism of those alleles, which results in a co-presence of castes in a population, enabling a persistence of the system. Such a study of genetic dynamics of interacting alleles can be a basis of analyses of evolution of interacting species.According to these studies, it was clearly indicated that interactions among species were variable, accompanied by alternation of system properties, which can stabilize the behavior of system in some situations. Less