In evolutionary biology, what defines a niche?

A niche is defined as the role and position that a species occupies in its environment, which includes the species' interactions with other organisms as well as its habitat, resource use, and behavior. This definition encompasses not just the physical space the species occupies but also how it contributes to the ecosystem, such as through its dietary habits, reproductive strategies, and interactions with other species, including competition and predation.

Understanding a niche is crucial in ecology because it highlights the functional aspects of how species live and thrive within their ecosystems. For example, two species may share a physical location but occupy different niches, which reduces direct competition and allows for a diverse range of species to coexist. By focusing on both the physical and ecological roles rather than just habitat or genetics, we gain a more comprehensive picture of how species interact with their environment.