Exercises: Trophic Levels and Energy Pyramids
In a grassland ecosystem in the Great Plains, grass is eaten by grasshoppers, grasshoppers are eaten by prairie dogs, and prairie dogs are eaten by hawks. Name the…
In a grassland ecosystem in the Great Plains, grass is eaten by grasshoppers, grasshoppers are eaten by prairie dogs, and prairie dogs are eaten by hawks. Name the trophic level (producer, primary consumer, secondary consumer, or tertiary consumer) of each of the four organisms.
Define the term energy pyramid* in your own words. Then state which trophic level is always found at the bottom of an energy pyramid and explain in one sentence why.
Define the term energy pyramid in your own words. Then state which trophic level is always found at the bottom of an energy pyramid and explain in one sentence why.
Emma draws an arrow from a rabbit to a coyote in a food chain diagram. What does the arrow represent? Say whether it points toward the organism that gives the energy or…
Emma draws an arrow from a rabbit to a coyote in a food chain diagram. What does the arrow represent? Say whether it points toward the organism that gives the energy or the organism that receives it.
An energy pyramid for a Florida salt marsh shows the following energy available at each level: | Trophic level | Energy available (kcal) | |---|---| | Cordgrass…
An energy pyramid for a Florida salt marsh shows the following energy available at each level:
| Trophic level | Energy available (kcal) |
|---|---|
| Cordgrass (producers) | 10,000 |
| Marsh snails (primary consumers) | 1,000 |
| Blue crabs (secondary consumers) | 100 |
| Raccoons (tertiary consumers) | 10 |
(a) What percentage of the energy at one level is available to the next level? (b) Name two ways energy from the cordgrass is "lost" before reaching the snails.
Draw or describe a food chain with four organisms found in the Chesapeake Bay. Label each trophic level and use arrows to show the direction of energy flow. Then state…
Draw or describe a food chain with four organisms found in the Chesapeake Bay. Label each trophic level and use arrows to show the direction of energy flow. Then state where the original source of energy for the whole chain comes from.
A producer level in a forest contains 50,000 kcal of energy. Assume that only 10% of the energy is passed to each next level. Calculate the energy available to the…
A producer level in a forest contains 50,000 kcal of energy. Assume that only 10% of the energy is passed to each next level. Calculate the energy available to the primary consumers and to the secondary consumers. Show each step.
Mateo notices that a lake ecosystem supports thousands of algae and insects, a few hundred fish, but only a handful of large predatory birds. Use the idea of energy…
Mateo notices that a lake ecosystem supports thousands of algae and insects, a few hundred fish, but only a handful of large predatory birds. Use the idea of energy transfer between trophic levels to explain this pattern. In your answer, include the approximate percentage of energy passed on, at least two ways energy is lost, and what this means for the maximum number of trophic levels an ecosystem can support.
A wildlife manager in Yellowstone studies two food chains: Chain A: grass → elk → wolf Chain B: grass → grasshopper → mouse → snake → hawk Assume 10% of energy passes to…
A wildlife manager in Yellowstone studies two food chains:
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Chain A: grass → elk → wolf
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Chain B: grass → grasshopper → mouse → snake → hawk
Assume 10% of energy passes to each level and the grass in both chains starts with 100,000 kcal. (a) Calculate the energy available to the top consumer in each chain. (b) Explain why a region can usually support more individuals of the top consumer in Chain A than in Chain B, and predict what would happen to the hawk population if the grasshopper population dropped sharply.