Symbiosis, in biology, it's an association of two living beings, two plants or a plant and an animal, in which both organisms receive benefits, even if in unequal proportions.
Some biologists consider that any relationship between two living beings involved in direct contact represents a symbiosis, not no matter which organism it benefits or harms, it is the case of parasites, which make their home in the body of another being, or even inside from him.
By extension, symbiosis means the common life. It is an association, between two living beings, who lead a life together. It's a concubinage.
symbiosis examples
the orchids they live in trees and rocks, places with a lot of organic matter but poor in mineral salts. However, its spongy-looking roots harbor fungi that decompose the organic matter in the substrate, which is transformed into mineral salts, which are assimilated by the plants. On the other hand, plants carry out photosynthesis and synthesize nutrients for the survival of the fungi.
the lichen it is the result of the symbiosis between the fungus and the alga, where the fungus provides shelter and moisture and the alga provides carbohydrates. They live as if they were a single being, are considered by some biologists as parasites, as if the fungi cultivated the algae for their own benefit.
Some cnidarians or coelenterates, such as hydras, harbor algae in their tentacles, which are mistaken for vegetation, mainly due to the greenish color of its body, which is due to the presence of unicellular green algae in its interior. These algae carry out photosynthesis, whose products are shared with hydras in a symbiotic relationship.