Remarks on the mechanism of demographic behaviour.

The main idea, on which discussion presented in this work is concentred cosists in the conviction, that the observed demographic regularities are the result of individual struggle with the daily difficulties of the units constituting populations, and the belief, that the essence of human existence is rooted in the permanent process of adaptations. On the base of above, it has been assumed that demographic transformations are result of two forces. First of them is formed by biological determinants, forcing human sociates to function in the environment in a way which would maximize both--ability to survive and multioly, and the result of these strifes in expressed by the guarantees of population existence. Resistance of environment is another force influencing demographic transformations.