A habitat is the place where an organism, population, species or community lives, whereas a niche describes the conditions and resources on which an organism or population depends. Put simply, a habitat is its “address”; a niche is its ecological “role” and requirements.
This is core SL and HL content in Subtopic 2.1, Individuals, populations, communities and ecosystems.
How Habitat and Niche Differ
A habitat is a physical location, such as a mangrove forest, freshwater pond or rocky shore. It contains the abiotic and biotic conditions experienced by organisms living there.
A niche describes how an organism fits into an ecosystem. It includes the resources it uses, the abiotic conditions it tolerates and its interactions with other populations, including competition, predation and mutualism.
| Feature | Habitat | Niche |
|---|---|---|
| Main idea | Where an organism lives | How it survives and interacts |
| Includes | Physical location and environmental surroundings | Resources, conditions and ecological interactions |
| Example | A rocky intertidal shore | Feeding on plankton, attaching to rock and tolerating exposure at low tide |
| Can be shared? | Many species can occupy the same habitat | Complete niche overlap creates competition |
For example, Chthamalus and Semibalanus barnacles may occupy the same rocky-shore habitat but have different tolerances and competitive relationships. Their distributions therefore reflect their niches, not simply their habitat.
At HL, this extends to fundamental niche and realized niche. The fundamental niche is the full potential range of conditions and resources a species could use; the realized niche is the narrower range it actually occupies after biotic interactions such as competition.
A common misconception is that habitat and niche are interchangeable. They are not: naming “a forest” identifies a habitat but does not explain a species’ resource use, tolerances or interactions.
Exam Technique
For a distinguish question, refer to both terms and state the contrast directly. For an explain question, connect niche requirements to species distribution using a specific ecological interaction or named example.