The realised niche of an organism is:
- AThe life pattern that the organism actually assumes
- BThe habitat of a species within a community resulting from clumping
- CThe habitat that exists in nature as opposed to the ideal
- DThe area a species can occupy in the face of exploitative competition
Show answer and explanation
Correct answers: (a) The life pattern that the organism actually assumes or (d) The area a species can occupy in the face of exploitative competition
Explanation
The fundamental niche is the full range of conditions and resources in which a species could live, with no competitors or predators. The realised niche is the part of it that the species actually occupies once competition and other interactions limit it. It is usually smaller than the fundamental niche.
- Option (d) defines the realised niche through competition: the area a species can occupy in the face of exploitative competition.
- Option (a), the life pattern the organism actually assumes, describes the same thing: the niche it really occupies.
Clumping (b) and the gap between real and ideal habitats (c) do not define a niche.
The book's key is (d). Option (a), the life pattern the organism actually assumes, is also a standard definition of the realised niche, so (a) is also accepted.