The Grinnellian niche refers to a concept in ecology that describes the specific set of environmental conditions and resources required for a species to survive and reproduce. Synonyms for this niche might include the ecological niche, the habitat niche, or the environmental niche. In biology, the term niche can also be used more broadly to describe the role a species plays in its ecosystem or community, such as predator or prey, pollinator, decomposer, or mutualist. Some other related terms might include the fundamental niche (the potential range of conditions a species could occupy), the realized niche (the actual range of conditions a species occupies in the presence of competition and other environmental constraints), or the niche overlap (the degree of similarity between the requirements of different species occupying the same habitat).