competition

competition in biology, relationship between members of the same or different species in which individuals are adversely affected by those having the same living requirements, such as food or space. Intraspecific competition, i.e., competition among members of the same species, is illustrated by some species of birds and mammals, the males of which set up territories from which all other males of the same species are excluded. In interspecific competition members of different species compete for the same ecologically limiting factors, such as a food source. Not all relationships among organisms are competitive; for example, the commensal relationship between members of different species is noncompetitive (see commensalism ).

competition The interaction between individuals of the same species (intraspecific competition), or between different species (interspecific competition) at the same trophic level, in which the growth and survival of one or all species or individuals is affected adversely. The competitive mechanism may be direct (active), as in allelopathy and mutual inhibition, or indirect, when a common resource is scarce. Competition leads either to the replacement of one species by another that has a competitive advantage, or to the modification of the interacting species by selective adaptation (whereby competition is minimized by small behavioural differences, e.g. in feeding patterns). Competition thus favours the separation of closely related or otherwise similar species. Separation may be achieved spatially, temporally, or ecologically (i.e. by adaptations in behaviour, morphology, etc.). The tendency of species to separate in this way is known as the competitive exclusion or Gause principle.

competition Interaction between individuals of the same species (intraspecific competition), or between different species (interspecific competition) at the same trophic level, in which the growth and survival of one or all species or individuals is affected adversely. The competitive mechanism may be direct (active), as when one organism releases a chemical substance that inhibits another, or indirect, as when a common resource is scarce. Competition leads either to the replacement of one species by another that has a competitive advantage, or to the modification of the interacting species by selective adaptation (whereby competition is minimized by small behavioural differences, e.g. in feeding patterns). Competition thus favours the separation of closely related or otherwise similar species. Separation may be achieved spatially, temporally, or ecologically (i.e. by adaptations in behaviour, morphology, etc.). The tendency of species to separate in this way is known as the competitive-exclusion principle.