A model of collisions of growing individuals: a further development

The process of collisions of growing circles was analytically explored. The resuled of the study consists of a consistent derivation of population dynamics from elementary interactions among individuals. The model developed gives an exponential law for the density decrease in a population of sedentary organisms. The approach has important implications for ecological researches of self-thinning in even-aged populations of such organisms. A hypothesis introducing a consideration of complicated structure of a population that undergoes self-thinning is discussed. The hypothesis views a natural population as a mixture of grades with different exponential laws of density decrease.