The scientific name for the job or role an organism plays in its habitat is its ecological niche.
A niche describes how an organism lives and functions in its environment. It includes the resources it uses, what it eats, when it is active, which conditions it can tolerate, and how it interacts with predators, competitors and other species. Habitat means where an organism lives; niche explains how it lives there.
Ecologists describe a species’ fundamental niche as the full range of conditions in which it could survive without biological pressures such as competition. Its realized niche is usually narrower because other organisms limit its access to food, space or shelter. A beaver, for example, not only uses a freshwater habitat but also changes it by building dams.
The word niche comes from a term meaning a recess or nest. A common mistake is treating niche as simply an organism’s address; its ecological role is the more precise meaning.