Ecology Reading Lesson · Grades 5–8

Habitats and Niches in an Ecosystem

A reading lesson on the ecology of habitats and niches. Students learn the difference between a habitat and a niche, how populations relate to each other in an ecosystem, and what happens when natural or human-caused changes upset the balance.

Reading Passage

Habitats and Niches in an Ecosystem

There are a number of habitats and niches in every ecosystem. Habitats are places where animals and other organisms live. A badger’s habitat is a hole in the ground. A frog’s habitat may be a pond or a stream. A niche is the particular activity of a species within the ecosystem. What an animal eats, what it needs to survive, and whether it is active during the day or at night are all examples of niches. The frog’s niche includes not only the pond where it lives, but also the insects it eats, the time of day it hunts, and the climate it needs to thrive.

A group of living things in a certain area is known as a population. Every population has a unique niche — no two are exactly alike. For two populations to have the same niche, they would need to live in the same space, reproduce the same way, eat the same things, and need the same conditions to grow. In other words, they would have to be the same species.

Sometimes changes occur in an animal’s habitat or in the larger ecosystem. One of the most common is a change in the weather — an especially rainy season, or a season with little rain at all. Usually, ecosystems stay in balance on their own. But sometimes a change upsets the balance and causes problems. A long dry period can cause a shortage of food.

In many cases, the change does not come from nature but from people. Once, in Australia, people decided to remove all of the feral cats from an island to protect a species of native seabirds the cats were hunting. The plan didn’t work the way they expected. Without cats, the population of wild rabbits — the cats’ other prey — grew enormously. The rabbits ate nearly all of the vegetation that the seabirds had used for shelter. In the end, the seabird population was more threatened without the cats than it had been with them.

This is a useful reminder of how connected the parts of an ecosystem are. Removing or adding even one species can ripple through every other population that shares the habitat. When humans want to help an ecosystem, the best results come from understanding the niches of every species before changing anything.

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