Explain the Symbiotic Relationships and their types?

Symbiosis : refers to a special type of association in which two species live together in a closely held relationship. In a broad sense, the term symbiosis has usually been used to describe relationships that are mutually advantageous to the species involved. However, symbiosis is now probably more aptly used to describe any close interrelationship between species even those that may benefit one of the parties while harming the other partner. In general, it can be said that the degree of benefit and harm varies considerably among the many symbiotic relationships that exist in nature.

Most biologists have supported an intriguing theory that attributes the evolution of major groups of organisms to a type of symbiosis that probably occurred in the early development of life. In contrast to prokaryotic cells, eukaryotic cells, among other things, have a membrane-covered nucleus containing DNA, double membrane organelles, and a cell wall consisting of cellulose rather than polysaccharides. According to Lynn Margulis theory, primitive prokaryotic cells ingested other prokaryotic cells, which continued to function internally within, providing for a symbiotic relationship that represented evolutionary selective advantages. This theory holds that eukaryotic cell organelles such as mitochondria and chloroplasts may have been derived from cells living symbiotically within other cells. There is compelling evidence that supports this theory.

Types of Symbiotic Relationships

There are three general kinds of symbiotic relationships: mutualism, in which both partners derive benefits, commensalism, in which one partner is helped and the other is not adversely affected, and parasitism, where one partner benefits and the other is harmed.