In the most simplest of terms, symbiosis can be described as a close and typically long-term association between two or more different biological species. The different types of symbiotic associations, namely commensalism, parasitism and mutualism, describe the nature of the relationship between the species. In commensalism, only one party is benefited from the association, whereas no harm is done to the other party. In parasitism, one party benefits from the association, while the other party is damaged or harmed. The party benefiting from the association is known as the parasite, whereas the party that is being harmed is known as the host. In some cases, the parasite damages the host only partially while using it to obtain important nutrients and water for survival. However, in some cases, the parasite continues to damage the tissues of the host until the latter dies. The parasite and then moves on to another specie to build another parasitic association with it and thus ensure its survival.
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Mutualism is described as a relation between two or more biological species in which all the parties benefit from the association. This kind of association is pretty common between plants and fungus.
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