Struggle for existence is a factor of evolution

Living organisms tend to reproduce exponentially.

Example:
offspring from one dandelion achene in the second year would be 100 individuals, in the fifth year – 107. In ten years, the offspring of one dandelion would cover the entire surface of the planet with a continuous carpet.

This example shows that many more individuals are born than can exist in a certain territory. Overpopulation does not occur, since most of the organisms that were born die for various reasons.

Individuals in nature do not exist in isolation, but in certain biogeocenoses. The success of their existence depends on relationships with other individuals that develop against the background of the action of abiotic factors.

Intense reproduction has two important consequences:

• the likelihood of the appearance of new hereditary deviations (mutations) increases;
• a struggle for existence arises.

Charles Darwin pointed out that the main reason for the struggle for existence is the contradiction between the ability of species for unlimited reproduction and a limited amount of vital resources.
The struggle for existence is a complex and diverse relationship of individuals within a species, between species and with unfavorable conditions of inanimate nature.
According to Darwin’s theory, the struggle for existence is a competition for food and habitat under conditions of overpopulation.

According to modern concepts (according to the synthetic theory of evolution – STE), elements of the struggle for existence can be any relationship – both competitive and mutually beneficial.