Symbiosis (Mutualism)
Mutualism is an example of symbiotic relationship in which each
organism benefits from the association. One type of mutualistic association
is that involving the exchange of nutrients, between two species,
a phenomenon called syntrophisms. Many microorganisms synthesis
vitamins and aminoacids in excess of their nutritional requirements.
Others have a requirement for one or more of these nutrients.
Symbiosis is an obligatory relationship between two populations
that benefit both the populations. Both populations are living together
for mutual benefit. The relationship between algae and fungi that result
in the formation of lichens is a classical example of mutualistic
intermicrobial relationship. Lichens are composed of primary producer,
the phycosymbiont (algae) and a consumer the mycosymbiont
(fungus).