Symbiosis

Symbiosis is an interaction or close living relationship between organisms from different species, usually with benefits to one or both species. Five types of relationships are recognized. Mutualism can be defined as an interaction between individuals from different species that brings beneficial effects to each species. An example of a mutual relationship is lichens. This mutually beneficial relationship consists of algae and a fungus. The fungi bring support and protection while obtaining food from the photosynthetic algae, in which bright colors are light-absorbing pigments. Commensalism is an interaction where one member of the association benefits and the other neither benefits nor is harmed. For example, when one microorganism (beneficial bacteria) produces an antibiotic against another organism (a pathogen) and provides protection to the plant associated with the beneficial bacteria. Amensalism is opposite of commensalism. It is the process when one organism is inhibited or damaged by the presence of another who does not benefit. For example, when a taller plant shades out a short plant. The shorter plant is adversely affected by the resulting scanty light available for its use in photosynthesis. Parasitism can be defined as an association between different species of organisms. The parasite (symbiont) depends on its host to meet its metabolic needs. It involves the uptake of substances that are nutrients to the parasite. They usually live inside or under their hosts, generally harming them, though they do not kill them immediately. In the Predation symbiotic relationship, one species (symbiont) kills another species (host). Unlike parasitism, the symbiont kills its host rather than harm for a long time. For example, some hermit crabs carry sea anemones in their shells, and when these are a period of starvation, they remove their anemones and feed on them. [Md. Jashim Uddin]