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group of organisms of the same species that live together at one at one time and interbreed

carrying capacity

the largest population that an environment can support at any given time


an interaction between two organisms in which one organism, the predator, kills and feeds on the other organism, the prey


the evolution of two or more species that is due to mutual influence, often in a way that makes the relationship more mutually beneficial


a relationship between two species in which one species, the parasite, benefits from the other species, the host, which is harmed


a relationship in which two different organisms live in close association with each other


a relationship between two species in which both species benefit


a relationship between two organisms in which one organism benefits and the other is unaffected


the unique position occupied by a species,both in terms of its physical use of its habitat and its function within an ecological community

fundamental niche

the largest ecological niche where an organism or species can live without competition

realized niche

the range of resources that a species uses, the conditions that the species can tolerate, and the functional roles that the species plays as a result of competition in the species' fundamental niche

competitive exclusion

the exclusion of one species by another due to competition

keystone species

a species that is critical to the functioning of the ecosystem in which it lives because it affects the survival and abundance of many other species in its community

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