Food Chains and Webs

Food Chains and Food WebsSarah Jones

Organisms have roles in ecosystems:

Producers - organisms that make their own food using the energy of sunlight - plants.

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Consumers - obtain their food by consuming other creatures - if they consume a producer then they are primary consumers or herbivores - if they consume herbivores they are secondary consumers or carnivores.

If they consume carnivores they are tertiary consumers or carnivores. Some species eat both producers and other consumers and they are called omnivores. Some creatures eat dead producers or consumers and are called detritivores.

Decomposers - Bacteria and fungi that break down dead organic material. Decomposers have an important role in ecosystems - they absorb nutrients from dead organisms or waste materials and return organic matter to the soil.

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Food chains are simple ways of representing feeding relationships among organisms.

Grass > insect > spider > bird

Food webs show the feeding relationship of all organisms in a particular location (food web = many food chains intertwined together).