Final answer:
The fundamental niche refers to the role and resources an organism uses in its environment, including interactions with biotic and abiotic factors and its function in the ecosystem, as opposed to its habitat, which is the physical environment it occupies.
Step-by-step explanation:
The fundamental (or physiological) niche refers to the role and resources an organism uses in its environment. This concept is critical in understanding how species interact with both the biotic and abiotic factors of their ecosystems. A niche includes aspects such as what an organism eats, how it obtains its food, its role in the flow of energy and recycling nutrients, and how it interacts with other organisms. An organism's niche is distinguished from its habitat, which is the physical environment to which the organism is adapted and within which it resides. Habitats encompass factors such as temperature, rainfall, and the availability of sunlight, all of which are crucial in shaping the traits required for an organism's survival.
An organism's niche is a more comprehensive term that goes beyond just where it lives (its habitat), to include its ecological functions and interactions. For instance, the niche of a species of bird might include its diet of certain insects, the way it captures its prey, its role in dispersing seeds through its droppings, and how it competes with other species. This broad ecological role prevents two different species from occupying the same niche within the same area for an extended period, due to the competitive exclusion principle.