Ecosystems

An Introduction to Ecosystems

By Alyssa Langley

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What is an ecosystem?

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Producers

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Consumers

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Decomposers

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Predator vs. Prey

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The Flow of Energy in an Ecosystem

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What kinds of ecosystems are there?

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An Australian Coral Reef

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A Rainforest

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The Sonoran Desert

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Want to learn more?

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Resources

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A Pond Ecosystem

What is an ecosystem?

An ecosystem is an area where there are living and non-living things. Another way to say this is that an ecosystem is made up of living organisms and their physical environments. Ecosystems can be big, such as the rainforest, or much smaller, such as a lake inside the rainforest. Interactions occur when one part of the system acts upon, or influences, another part of the system. Organisms within ecosystems interact with each other in both positive and negative ways. Organisms also interact with non-living elements of an ecosystem. Non-living elements of an ecosystem can even interact with each other!

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Producers

A producer is a certain type of organism found in an ecosystem. Producers are also known as autotrophs because they use energy from the sun or from certain chemicals to make their own food in a complex process known as photosynthesis. Most producers are plants and they are incredibly important to every ecosystem. In each ecosystem, there are many more producers than consumers. All animals depend on producers for the energy that they need to survive.

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Consumers

Consumers are organisms that eat other organisms (animals or plants) for food because they cannot make their own food.They are also known as heterotrophs. Consumers help keep ecosystems balanced by keeping animal populations at a reasonable number.

There are three different types of consumers : carnivores, herbivores, and omnivores. A carnivore eats mainly meat (other animals). A herbivore eats mainly plants. An omnivore eats both animals and plants.

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Fungi

Decomposers

Decomposers are very important in an ecosystem because they break down waste and dead plants and animals for food. Without decomposers, waste would be everywhere!

Decomposers can be fungi, bacteria, or animals known as scavengers. Scavengers find dead plants and animals and eat them. Examples of scavengers include flies and worms.

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Predator vs. Prey

Organisms in an ecosystem can be classified as either predator or prey. A predator is an organism that feeds on another organism and causes its death. Prey is the organism that is fed on and killed. A species of animal can be both predator and prey in different situations.

A predator chasing his prey

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A Food Web

Food Webs and the Flow of Energy in an Ecosystem

Food webs represent the predator/prey relationships in an ecosystem. This type of chart also shows the flow of energy from producers to consumers. Producers transfer the energy from the sun into food for consumers. Consumers eat the plants and store the energy. Other consumers eat these consumers and store that energy etc.

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What kinds of ecosystems are there?

Ecosystems are defined based on what types of organisms live there and by the geography that separates one place from another. Sometimes it can be hard to define ecosystems that are similar because many parts of them may overlap.

There are many different types of ecosystems. Here are some examples: a rainforest, a desert, a prarie, a savanna, and a coral reef. You can see pictures of a few of these on the next pages.

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