The basis of the emergence and existence of biocenoses is represented by the relations of organisms, their relationships, into which they enter into each other, inhabiting the same biotope. These connections determine the basic condition of life in the community, the possibility of obtaining food and conquering a new space. Living organisms do not settle with each other by chance, but form certain communities adapted to live together. Thus, they contribute to the evolution of each species entering into a relationship, provide living conditions for themselves, thereby contributing to the creation of conditions for another species. Mutually beneficial relationships, for example, symbiosis (cohabitation, from the Greek sym together, bios life) is a form of relationship in which both partners or one of them benefits from the other. There are several forms of symbiosis.
Cooperation. Well-known cohabitation of hermit crabs with soft coral sea anemone polyps. Cancer settles in an empty shell of a mollusk and carries it on itself together with a polyp. Such cohabitation is mutually beneficial: moving along the bottom, the cancer increases the space used by the sea anemone to catch prey, part of which falls to the bottom and is eaten by the cancer.
Mutualism (from Latin mutuus mutual). A form of mutually beneficial relationships of species from temporary, optional contact to the symbiosis of an inseparable useful relationship between the two species. Lichens are the cohabitation of fungus and algae. In the lichen, fungal hyphae, braiding the cells and threads of algae, form special suction processes that penetrate the cells. Through them, the fungus receives photosynthesis products formed by algae. Algae from the hyphae of the fungus extracts water and mineral salts. In total, there are more than 20,000 species of symbiotic organisms in nature. Intestinal symbionts are involved in the processing of coarse plant foods in many ruminants. Mutualistic relations, for example, between Siberian cedar pine and cedar pine, nuthatch and cuckoo birds, which, while eating pine seeds and storing food, contribute to the self-renewal of cedar forests, are less binding, but extremely essential.