mutualism

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Related to mutualistic: Symbiotic Relationships

Mutualism

An interaction between two species that benefits both. Individualsthat interact with mutualists experience higher sucess than those that do not.Hence, behaving mutualistically is advantageous to the individual, and it doesnot require any concern for the well-being of the partner. At one time,mutualisms were thought to be rare curiosities primarily of interest to naturalhistorians. However, it is now believed that every species is involved in oneor more mutualisms. Mutualisms are thought to lie at the root of phenomena asdiverse as the origin of the eukaryotic cell, the diversification of floweringplants, and the pattern of elevated species diversity in tropical forests.

Mutualisms generally involve an exchange of substances or services thatorganisms would find difficult or impossible to obtain for themselves. Forinstance, Rhizobium bacteria found in nodules on the roots of manylegume (bean) species fix atmospheric nitrogen into a form (NH3)that can be taken up by plants. The plant provides the bacteria with carbon inthe form of dicarboxylic acids. The carbon is utilized by the bacteria asenergy for nitrogen fixation. Consequently, leguminous plants often thrive innitrogen-poor environments where other plants cannot persist. Anotherwell-known example is lichens, in which fungi take up carbon fixed duringphotosynthesis of their algae associates.

A second benefit offered within some mutualisms is transportation. Prominentamong these mutualisms is biotic pollination, in which certain animals visitflowers to obtain resources and return a benefit by transporting pollen betweenthe flowers they visit. A final benefit is protection from one's enemies.For example, ants attack the predators and parasites of certain aphids inexchange for access to the aphids' carbohydrate-rich excretions(honeydew).

Another consideration about mutualisms is whether they are symbiotic. Twospecies found in intimate physical association for most or all of theirlifetimes are considered to be in symbiosis. Not all symbioses are mutualistic;symbioses may benefit both, one, or neither of the partners.

Mutualisms can also be characterized as obligate or facultative (dependingon whether or not the partners can survive without each other), and asspecialized or generalized (depending on how many species can confer thebenefit in question).

Two features are common to most mutualisms. First, mutualisms are highlyvariable in time and space. Second, mutualisms are susceptible to cheating.Cheaters can be individuals of the mutualist species that profit from theirpartners' actions without offering anything in return, or else otherspecies that invade the mutualism for their own gain.

Mutualism has considerable practical significance. Certain mutualisms playcentral roles in humans' ability to feed the growing population. It hasbeen estimated that half the food consumed is the product of bioticpollination. See Ecology, Plant pathology

mutualism

[′myü·chə·wə‚liz·əm]
(ecology)
Mutual interactions between two species that are beneficial to both species.
References in periodicals archive ?
While these interactions are of a mutualistic nature like that of the orchids, they use the fungi as an intermediary to steal carbohydrates (sugars) directly from trees without providing anything in return to their arboreal hosts.
Promoted synthesis of secondary metabolism in plants is one of important defense mechanisms, some evidences also showed that secondary metabolisms in plants were associated with DSE mutualistic association under drought stress (Nascimento and Fett-Neto, 2000).
While the Ina feed on them, in return humans have longevity and pleasure in this mutualistic symbiosis.
This shows a mutualistic relationship between Scutellospora nigra and Burkholderia multivorans.
Three-way interactions among mutualistic mycorrhizal fungi, plants, and plant enemies: hypotheses and synthesis.
Previous studies also showed that hemipteran species that occur within the same habitat may compete for the mutualistic services of ants (Bristow 1984, 1991; Cushman 1991).
acnes, it is considered a mutualistic part of the skin flora, acting against more pathogenic organisms on the skin, such as S.
Mutualistic interaction of rhizobacteria with arbuscular mycorrhizal fungi and its antagonistic effect on Fusarium oxysporum in Carica papaya seedlings.
mutualistic to pathogenic, parthenogenesis, cytoplasmic incompatibility, selective male killing and feminization (1).
Instead, orchids form a mutualistic relationship with mycorrhizal fungi that help germinate the seeds and supply them with the necessary nutrients for growth.