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Windows to the Universe
Biomes and Ecosystems
Biomes are large regions of the world with similar plants, animals, and other living things that are adapted to the climate and other conditions. Explore the links below to learn more about some of the Earth's biomes.
A biome is made of many similar ecosystems. An ecosystem is often much smaller than a biome, although the size varies.
Ecosystems are defined by the interactions between living things and the nonliving things in a place. In an ecosystem, the plants, animals, and other organisms rely on each other and on the physical environment – the soil, water, and nutrients, for example.
An ecosystem is made of different species. All of the individuals of the same species in an ecosystem are called a population. One ecosystem might have hundreds or thousands of populations of different species.
Even though they are living in the same place, each species has its own role to play in an ecosystem. This role is called a niche. The niche for one species might be to climb trees and eat their fruit, while the niche for another species might be to hunt for small rodents. For a tree, a niche might be to grow tall and make food with the Sun’s energy through the process of photosynthesis. If the niche of two species is very similar, they might compete for food or other resources.
Sometimes ecosystems get out of balance. If, for example, it rains a lot and a population that thrives with extra water increases in number, the larger population might crowd out other species in the ecosystem. They might take food or space or other resources from other species. They might eat all the food. Sometimes balance is restored naturally in an ecosystem. Other times the ecosystem will become more and more out of balance. Today, human actions are having an impact on ecosystems all over the world. These actions are sending many ecosystems out of balance.
