This phenomenon is quite widespread in nature. It was called mutualism (examples of mutualism among plants and animals, see below). The word itself comes from the British mutual mutual. To understand its essence, one must know what the phenomenon is different from the symbiosis, more General concepts in biology. This is also the coexistence of different species of plants and animals. But symbiosis can happen and unfavorable to any of the participating partners. Mutualism implies mutual benefits involved.
What is mutualism in biology? Plants and animals, engaging in such relations, get some benefit from the coexistence and benefits. For example, one partner uses the second as a supplier of food. And this second partner receives shelter from enemies and the conditions that favour breeding. Examples of mutualism in nature may be different. One kind of gets enough food, and in return spreads the seeds or relieve a partner from parasitic organisms. Moreover, each of the members of the pair tend to act very selfishly, maintaining these relationships.
Sometimes as a result of such cooperation have arisen and closer to physiological contact. This is mutualism plants. Examples of their close cooperation with the mushrooms is so tactile that occurs special education – grimacing – the joint brainchild of a fungus and the root. This close interspecific contact and creates a joint interspecies evolution. Often mutuality and settled together, and have mutual adaptations for coexistence (for example, the flowering and pollinating).
Mutualism. Examples of coexistence in nature
A striking example of such phenomena in nature is a kind of cooperation between Actinia and fish-clown. This happens in the following way. The clown swims to sea anemones and gave her sting, to be able to determine the composition of mucus, with which it is covered (the mucus gives her herself to sting). Then the fish reproduces the composition of mucus. And after that painless for your health, hiding from enemies who are at risk to be stung among the tentacles of a marine animal (sea anemone, according to the classification belongs to the animal world, and not to plants). Clown fish, in turn, cares about the sea anemones in which they live: carries away food debris and keeps the place cool. And never not sailed from roommate. This is interspecific mutualism.
Examples of animals that fall under this phenomenon (when one organisms lives in another) – ruminants. Like we can see in all ruminants. Cow, as you know, some products can not digest itself. Such compounds include cellulose. As in plants consumed by the cow, it's plenty. In this case the ruminants cows have a special organ called a rumen (part of GIT). This cavity, where there are millions of microorganisms. They help the cow to digest cellulose. And ruminant, if the food is not fully digested, again to burp her, so she again fell into the rumen, where it is treated with microbes. It can continue several times until the food is finally digested. The rumen of a cow (or other ruminant) – a closed ecosystem in miniature, where there are many microorganisms, whose task is to facilitate the digestion. A bovine animal in return gives them a place to live and food. This is mutualism.
Examples of this phenomenon – the unions, to be concluded between higher plants and fungi. The root system of these plants is formed by means of fungal filaments plus their own root tissue, sometimes leading to merging the fabrics. The fungi supply the plant minerals required for its nutrition, and the plant provides accommodation and meals mushrooms (fallen leaves, humus, etc.).
Soft and hard
Interspecific mutualism can be extremely necessary and vital for both. So, some of the higher flowering plants simply won't be able to breed and produce offspring without animals acting as their pollinators: insects and birds. Then mutualism is called hard. But if interspecies cooperation is optional (roughly speaking, you can do without it) is soft.
Examples of such cooperation is interaction of marine shrimp Alphaeus, and steers (meaning fish). Shrimp are able to build burrows in which to hide gobies when approaching any kind of enemies. And visually impaired shrimp, interacting with hiding in the burrow with the goby, receives information about changes in the situation.
Entire systems of interaction of insects, plants, ticks, mushrooms exist in pine and deciduous forests, where every rotten stump can be considered an example of a mutualistic hostel.
There is also mutualism, involving the breeding of some species by others. People and wild plant. The ant and the caterpillar of the butterfly Blues. Beetles and fungi. All examples of the phenomenon, when one is engaged in a kind of breeding other (for food or other purposes), and the latter has for this abundant food, and the ability to actively proliferate.