Ivan Dmitrievich Strelnikov. Part 2. Scientific activities

The article describes and analyzes the scientific activity of the remarkable Russian / Soviet biologist Ivan Dmitrievich Strelnikov. In his long and eventful life, the main areas of his scientific work were: immunology, border areas between ecology and physiology (physiological ecology, the influence of sunlight and temperature on physiology and ecology of different groups of animals - insects, mollusks, crustaceans, reptiles and mammals). He was the first to clarify and place emphasis on the fact that body temperature in the state of "active life" in many (especially flying) insects, reptiles and other ectothermic animals on land is as high as that in endothermic mammals (about 35-40º). He was the first to apply the methodological complex of research, which can be called "experimental ecology" and became the full founder of such an area of science as physiological ecology, which is important in theoretical and applied terms. He studied the allometric dependencies between body size, brain size, the intensity of physiological processes, speed and quality of adaptive processes, speciation. The smaller a body size, the more intense the physiological processes, and the more species in a genus. The more complex the habitat (three-dimensionality, etc.), the more complex the animals’ behavior, and the larger their brain.