[Species senescence: fact or illusion?]

A brief review of the studies on "species senescence, was presented. The evidences on the existence of this phenomenon were analyzed (mass extinctions, "laws" of evolution). The mechanism of evolution, which could lead to "species senescence" was formulated: organisms inevitably tend to produce copies of themselves; organisms are incapable to produce their exact copies; species transform inevitably with the changes of generations even if they are already well adapted to their environment; such a continuous transformation takes place in definite directions because of physical and chemical constraints even if these directions lead to extinction.