What is the difference between a habitat and a niche?

A habitat is where an organism lives, while a niche refers to an organism's role within its habitat.

A habitat is the physical environment in which a species lives and is characterised by specific physical and biological conditions. It is essentially the 'address' of an organism within an ecosystem. For example, a forest could be a habitat for a bird, while a pond could be a habitat for a frog. Habitats can vary greatly in size; they could be as large as an ocean or as small as a leaf. They provide the organism with the necessary conditions for life, including food, water, temperature, light, and shelter.

On the other hand, a niche is a term that describes the role an organism plays within its habitat. It encompasses not only the physical space that an organism occupies, but also its interactions with other organisms and its use of resources within the habitat. A niche is like the 'job' or 'profession' of an organism in an ecosystem. For instance, the niche of a bee might include pollinating flowers, while the niche of a lion might include hunting and killing other animals for food.

The concept of a niche is crucial in understanding the dynamics of ecosystems. Each species within an ecosystem has a unique niche, and no two species can occupy the exact same niche for a prolonged period. This is known as the competitive exclusion principle. If two species attempt to occupy the same niche, they will compete for resources until one species is driven out or becomes extinct in that location.

In summary, while a habitat refers to the 'where' of an organism's existence, a niche refers to the 'how' - how it survives, how it interacts with other organisms, and how it uses the resources available in its habitat. Both concepts are fundamental to the study of ecology and biodiversity.