Two similar organisms competing for resources when one has a slight reproductive advantage which leads to the elimination of the other organism. A fundamental niche potentially occupied by that species. A realized niche is a portion of the fundamental niche it actually occupies in a certain environment.
Keeping this in view, can a realized niche can be larger than a fundamental niche?
No, because it neither gains nor loses from the commensual relationship. Habitat is where an organism lives. Its niche is the role it plays in that habitat. The realized niche can be smaller than, or the same size as, the fundamental niche, but never larger.
Why is the realized niche smaller than the fundamental niche?
A niche may be defined as the way in which an organism utilizes its environment. Interspecific interactions may cause a species' realized niche to be smaller than its fundamental niche. If resources are limiting, two species normally cannot occupy the same niche indefinitely.
What is the definition of a fundamental niche?
A niche includes more than what an organism eats or where it lives. Environmental factors, such as climate, soil chemistry, and elevation, also play a role in defining a niche. A fundamental niche is the term for what an organism's niche would be in the absence of competition from other species.