Practice AP Environmental Science questions on energy transfer, trophic levels, the 10% rule, and decreasing energy between levels.
Wetlands were once considered to be wastelands. Over 50 percent of the United States original wetlands have been destroyed.
Wetlands are highly productive ecosystems with complex food webs.
Explain why it takes many hectares of wetland to support a pair of eagles.
Explain why it takes many hectares of wetland to support a pair of eagles.
(2 points: 1 point for each correct explanation)
- To support a pair of eagles, there must be a large amount of biomass at lower trophic levels.
- Less energy is available at each successive trophic level, because as energy moves up the food chain, much of it is:
- lost as heat (10 percent rule) or lost as metabolic work; or,
- transformed into a less usable form/becomes less organized (second law of thermodynamics).
- Some biomass is not digestible at the next trophic level (e.g., cellulose, chitin). Note: Students may use a trophic pyramid diagram, but it must be accompanied by an explanation in order to earn credit.