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AP Environmental Science / Unit 1: The Living World: Ecosystems

1.10 Energy Flow and the 10% Rule

3 practice questions

Notes

Only about 10% of energy passes from one trophic level to the next; the rest is lost as heat (second law of thermodynamics).

  • This limits food chains to a few levels.
Producers: 10,000 kcalPrimary consumers: 1,000 kcalSecondary consumers: 100 kcalTertiary consumers: 10 kcal
About 10% moves up each level.

Practice

Producers have 50,000 J. Tertiary consumers get about:
Why are food chains short?
Most energy lost between levels becomes:

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