Life means Struggle

The concept of the struggle for life is closely related to natural selection. In the most general sense, the struggle for life derives from the disparity between the great capacity of organisms to multiply and the limited amounts of space, food, water, and so forth necessary for the normal existence of organisms of any species. Thus, according to the calculations of Darwin, under the condition that all offspring survived and bred, a pair of elephants, one of the most slowly multiplying mammals, in 750 years would leave 19 million offspring. One diatom, with unrestricted multiplication, in 36 hours could cover the entire surface of the earth with a flim.

However, this potential capacity for multiplication is never fully realized in nature. The majority of the individuals that appear do not survive to adulthood and die in the process of direct or indirect struggle for life—that is, die under the effect of unfavorable climatic or other abiotic environmental factors (constitutional struggle for life), in the struggle with representatives of other species (interspecific struggle for life), or in a struggle with others of its own species (intraspecific struggle for life). Constitutional and interspecific struggle for life, in and of themselves, are only eliminating factors. Only the intraspecific struggle leads to the creation of new forms of organization. Among the factors which result from the competition of different individuals of the given species in the struggle for life and multiplication are selective elimination; general, or random, elimination; individual elimination (which includes the direct elimination by physical factors and biological factors as well as indirect elimination by physiological factors, which leads to the survival of the fitter individuals); and family and group elimination. The combination of individual and group elimination is of particular significance in evolution. Elimination assumes a selective character only through competition, which can be intragroup (active and passive individual), interfamily, and intergroup (I. I. Shmal’gauzen).

Intraspecific struggle for life is manifested in the competition between individuals of a given species when they encounter any enemies or harmful influences, in the competition for food and other vitally necessary factors such as water and light, and in the competition for the more effective protection of their life and offspring. Interspecific struggle for life can occur directly between the predator and the victim as well as between the individuals of different, often very distant, species. For example, herbivorous mammals and herbivorous insects (for example, locusts and crickets) compete or “struggle” for food.