Ecosystem Food Webs

Use the image below. If snakes were eradicated (or their population decreased), what would we expect to happen to the mongoose population and why?

• the mongoose population would increase without a predator
• the mongoose population would decrease without a predator
• the mongoose population would decrease without a food source
• the mongoose population would remain constant

Use the image below. Which of the following organisms has the least amount of available energy?

• ladybug
• frog
• grass
• hawk

Use the image below. Which of the following organisms has the greatest amount of available energy?

• ladybug
• frog
• grass
• hawk

Use the image below. If a disease wipes out the grasshopper population, what might happen?

• the snake population would dramatically increase
• the skunk population would dramatically decrease
• small birds may struggle to find a food source and their population may decrease
• mice would emigrate into the environment

6. The diagrams below represent possible energy pyramids for the food web above. Which energy pyramid CORRECTLY represents the amount of energy available to each level?

• A.
• B.
• C.
• D.

7. Which of the following statement BEST describes why an energy pyramid is shaped the way it is?

• a. The organisms toward the top of the pyramid rely directly on the sun.
• b. Less energy is available for the upper levels.
• c. More energy is available to the upper levels .
• d. Populations are larger as you move to the top of the pyramid.

8. Imagine that people released python snakes that they could no longer keep as pets into this ecosystem. The ecosystem was well balanced until snakes were added to it. Although python snakes had never been in this ecosystem, they survived very well by eating many oriole birds. What would most likely happen after the snakes (who eat orioles) were added to this ecosystem?

• a. The insect population may go up causing more damage to the rosebushes.
• b. The insect population would go down so the rosebushes would grow bigger and better.
• c. The oriole population would go up because there would be more insects to eat.
• d. The addition of snakes wouldn’t affect the ecosystem because it was already balanced.

Looking at this Energy Pyramid, which trophic level stores the largest amount of energy?

• The first trophic level - the primary producers
• The second trophic level - primary consumers
• The third trophic level - secondary consumers

Which group of organisms on this food chain stores the largest amount of energy?

• the leaf (plant) population
• the caterpillar population
• the chameleon population

Why does the Energy Pyramid get more narrow as you move up the food chain towards the highest trophic level (the top consumer)?

• The energy pyramid is showing that there is less for decomposers to eat at the top
• The energy pyramid is showing that energy is being lost at every trophic level, leaving less available energy for the next level
• The energy pyramid is showing that there are fewer organisms on each trophic level
• The energy pyramid is showing which trophic level is most important to the ecosystem