Interspecific Competition

Terms:
mutualism, commensalism, amensalism, competitive exclusion principle (Gause's Principle), Lotka-Volterra equations, stable and unstable equilibrium, resource partitioning, ghost of competition past, competitive or ecological release, predator mediated competition, realized and fundamental niche, character displacement, evolutionary stable strategy (ESS), allelopathy

amensalism: An interaction between two species or individuals that has no effect on one and is negative on the other.

allelopathy:  A mechanism whereby plants can avoid competition with other plants by producing a chemical that prevents other plants from growing near or around it. 

character displacement:  When a morphological character in closely related species varies between these species in a way that allows them to avoid competition and overlapping niches. 

commensalism: An interaction between two species or individuals that is beneficial to one and has no effect on the other.

competitive or ecological release:  When a species is able to grow freely in its fundamental niche after a competitor is removed from a system. 

competitive exclusion principle (Gause’s Principle):   Principle that states that no two species can share all the same limited resources without one being excluded. 

Evolutionary Stable Strategy (ESS):  Development of a phenotype that is most fit for a given environment.

fundamental niche:  The entire habitat and area where a species would occur if not for interactions with other species that prevent this. 

Ghost of Competition Past:   Attributing a pattern in nature, such as resource partitioning or character displacement between closely related species, to competition that occurred in the past. 

Lotka-Volterra equations: Mathematical equations and models that describe population growth under a variety of conditions.

mutualism: An interaction between two species or individuals that is beneficial to both.

predator mediated competition:   When a predator mediates competition between two species that allows those species to coexist. Otherwise, a strong competitor would exclude the weaker species.  The predator feeds on the stronger thereby allowing the weaker to survive in the same niche as the stronger. 

realized niche:  The niche in which a species occurs, usually smaller than its fundamental niche where it could occur if no interactions with other species prevented it from doing so. 

resource partitioning:   Species feeding on a resource in different places, or partitions, presumably to avoid interspecific competition. 

stable equilibrium: When the relative number of two coexisting species does not change through time, despite disturbances that may temporarily decrease one or both species.

unstable equilibrium: When the relative number of two coexisting species remains unchanged through time unless a disturbance occurs to the system.