UPSC Prelims 2013 Q48: Environment & Ecology – Ecosystems & Ecology Concepts
Which one of the following terms describes not only the physical space occupied by an
organism, but also its functional role in the community of organisms?
- (a) Ecotone
- (b) Ecological niche
- (c) Habitat
- (d) Home range
Answer: (b) Ecological niche
Explanation
Ecological niche
An ecological niche is the place a species lives in plus the role it plays there: what it eats, what eats it, when it is active.
| Term | Meaning |
|---|---|
| (a) Ecotone | Transition zone between two ecosystems, such as a mangrove or estuary |
| (b) Ecological niche | Physical space and functional role of an organism |
| (c) Habitat | Only the place where an organism lives |
| (d) Home range | The area an animal moves over in its normal life |
Easy way to remember:
| Term | Compared to |
|---|---|
| Habitat | The organism's address |
| Niche | The organism's profession |
Related ideas: the edge effect (more species in an ecotone); competitive exclusion (two species cannot hold the same niche for long).
Answer: (b) Ecological niche.
Why each option is right or wrong
- (a) Incorrect. An ecotone is the boundary zone between two ecosystems.
- (b) CORRECT. An ecological niche covers both space and functional role.
- (c) Incorrect. A habitat is only the physical space, without the role.
- (d) Incorrect. A home range is the area an animal regularly covers.
Key point
Niche = habitat + functional role ('profession'). Habitat = address. Ecotone = transition zone with edge effect.
Remember
Niche = address + profession.
Common mistakes
- Confusing niche with habitat, which is only the place.
- Forgetting that the question asks for space and role together.
- Mixing up ecotone and ecological niche.
Exam tip
Habitat is where it lives; niche is how it lives.
Sources
- NCERT Class XII — Biology (Organisms and Populations)
- E.P. Odum — Fundamentals of Ecology (habitat and ecological niche)