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Matter and energy in food webs

Review your understanding of matter and energy in food webs in this free article aligned to NGSS standards.

Key points:

  • Matter describes the atoms that make up an ecosystem’s parts. Matter cycles between the living and nonliving parts of an ecosystem.
  • Energy changes form as it moves through an ecosystem. Energy that enters an ecosystem eventually leaves as heat.
  • Producers are organisms that make their own food inside their cells. Photosynthetic organisms are producers. Producers allow energy to enter an ecosystem.
  • Consumers are organisms that eat other organisms. When this occurs, the matter and energy stored in the other organism’s biomass moves to the consumer.
    • Primary consumers eat producers.
    • Secondary consumers eat primary consumers.
  • Decomposers are organisms that consume dead plant and animal matter. When they do this, they return matter back to the environment.
  • Food webs are models that show how energy and matter move in an ecosystem. The arrows in a food web show what organisms eat. The arrows point away from the organism being eaten, and toward the organism doing the eating.
An ocean food web.

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