two organisms living together for their mutual benefit
Symbiosis
title: Mutualism (biology) text: Mutualism (biology) Mutualism or interspecific cooperation is the way two organisms of different species exist in a relationship in which each individual fitness benefits from the activity of the other. Similar interactions "within" a species are known as co-operation. Mutualism can be contrasted with interspecific competition, in which each species experiences "reduced" fitness, and exploitation, or parasitism, in which one species benefits at the "expense" of the other. Symbiosis involves two species living in close proximity and may be mutualistic, parasitic, or commensal, so symbiotic relationships are not always mutualistic. A well-known mutualism is the relationship between ungulates (such as title: Ectosymbiosis text: found frequently in organisms that attach themselves to larger species in order to move long distances or scavenge food easily; this is documented in remoras which attach to sharks to scavenge and travel. An additional ectosymbiotic example of commensalism is the relationship between small sessile organisms and echinoids in the Southern ocean, where the echinoids provide substrate for the small organisms to grow and the echinoids remain unaffected. "Main article:" Mutualism Mutualism is a form of ectosymbiosis where both the host and parasitic species benefit from the interaction. There are many examples of mutualistic ectosymbiosis that occur in nature. One title: Cooperation text: Cooperation Cooperation (sometimes written as co-operation) is the process of groups of organisms working or acting together for common, mutual, or some underlying benefit, as opposed to working in competition for selfish benefit. Many animal and plant species cooperate both with other members of their own species and with members of other species (symbiosis or mutualism). Humans cooperate for the same reasons as other animals: immediate benefit, genetic relatedness, and reciprocity, but also for particularly human reasons, such as honesty signaling (indirect reciprocity), cultural group selection, and for reasons having to do with cultural evolution. Language allows humans to cooperate title: Biological interaction text: they cause to each partner. Mutualism is an interaction between two or more species, where species derive a mutual benefit, for example an increased carrying capacity. Similar interactions within a species are known as co-operation. Mutualism may be classified in terms of the closeness of association, the closest being symbiosis, which is often confused with mutualism. One or both species involved in the interaction may be obligate, meaning they cannot survive in the short or long term without the other species. Though mutualism has historically received less attention than other interactions such as predation, it is an important subject in title: Symbiosis text: Symbiosis Symbiosis (from Greek συμβίωσις "living together", from σύν "together" and βίωσις "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic. The organisms, each termed a symbiont, may be of the same or of different species. In 1879, Heinrich Anton de Bary defined it as "the living together of unlike organisms". The term was subject to a century-long debate about whether it should specifically denote mutualism, as in lichens; biologists have now abandoned that restriction. Symbiosis can be obligatory, which means that one or both of the