I'm really confused about these principles of ecology...!?

Question

First of all, what exactly is a niche? Is it where an organism lives its life? Can a habitat include only one niche? Does a species' niche include how the species meets it's needs for food and shelter? Is it true that centipedes and worms under a log can occupy the same habitat but have different niches?

I'M SO CONFUZED!

Answer 1

Niche and habitat are closely related, but they are not the same thing. Habitat is where an organism lives. Niche is the way an organism fits into the ecosystem -- the organism's role or job in the ecosystem.

Think about a squirrel in your yard. The squirrel's habitat is the yard, including the trees it climbs and all the surroundings. It's where the squirrel lives. The habitat must provide what the squirrel needs to live.

Now what is the squirrel's niche. Think of what the squirrel does, what the squirrel needs, and what the squirrel provides to other parts of the ecosystem.
-- Builds its nest high in the tree.
-- Eats seeds from the trees, from the bird feeder, ...
-- Needs a supply of water.
-- Buries seeds in the yard, some of which don't ever get dug up and consequently grow into more trees.
-- Sometimes caught and eaten by dogs.
-- Provide a home for their parasites.
-- Nests provide shelter for a variety of insects and spiders.

Even though other organisms live in the yard, they don't have exactly the same niche as a squirrel. A bluejay will eat the same seeds as the squirrel, but bluejays don't bury the seeds, don't build the same kinds of nests, don't use the same parts of the tree for shelter, etc.

A centipede and a millipede can live in the same habitat, but the millipede feeds on dead organic matter while the centipede is a predator. Therefore, they don't play the same roles in the ecosystem, and they don't have the same niche.