Communities

 

Symbiosis

Two species who have a symbiotic relationship have a close, long-term association. This relationship can be as close as the green algae Zoochlorellae that live with sea anemones, providing the anemone with sugar, a by-product of photosynthesis. The green algae gains protection, and nutrients from the anemone's meals. This same genus of plants are found in many other animals, living in the same close symbiotic relationship.

The above symbiosis describes mutalism, but there are two other forms of symbiotic relationships. Commensalism describes a cooperation between two species that is beneficial to only one species. In such a relationship, the other species is not harmed. The third form of symbiosis is parasitism, where one species benefits to the detriment of the other species. The host species is harmed, from as mild a loss as losing nutrients to feed the parasite, to as harmful as dying due to the parasite's activities.