Food Webs and Ecosystems

Three Main Jobs

There are three big jobs for the members of our ecosystem and they each have different, but important roles in the functioning of our Earth. The species in our ecosystems are each responsible for certain roles.

We can start learning about the roles in our ecosystem by first discussing what producers do. These are the species that produce food for other animals. The next job is the role of the consumer, who eats the producers for food and serves as food for the secondary and tertiary consumers. The consumers will eventually die and the natural organisms that compose them will return to the earth as food for the producers. This therefore shows the cycle that defines the relationships between the various groups.

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The food chain above is an example of a grasslands ecosystem. The red arrows demonstrate
the relationships between the different species.

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1. This pyramid is another way ecologists separate the various roles of the species that make up ecosystems. Ecologists use a certain kind of pyramid that shows the relationships between producers and consumers. The pyramid represents the correct proportions of animals in their ecosystem.
2. If you start at the bottom of the pyramid, this is the largest part of the cycle because they are the organisms that feed the rest of the species in the pyramid. Above the decomposers are the producers that feed off of the decomposers and serve as nutrition for the consumers. Then the consumers are divided into sections: primary, secondary and tertiary. The tertiary consumers sit at the top of the pyramid and are in the smallest section because there are not as many of them.
3. This pyramid as well as the cycle depends on a balance between all of the different levels. Changes to the pyramid, at any level, can throw off the entire food chain for an ecosystem. All of the elements that compose an ecosystem must remain in balance for it to continue to work effectively.

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