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Question 24

In this model food web the only feeding links are these: snails eat algae; small fish eat algae; frogs eat snails; herons eat small fish. Frogs are the only predator of the snails in this web, and algae remain plentiful, so food is not a limiting factor here. If all the frogs are removed and nothing else in this web changes, what happens to the snail population?

  1. It decreases, because the small fish then eat the snails
  2. It decreases, because the algae disappear once the frogs are gone
  3. It stays the same, because the herons control the snails instead
  4. It increases, because its only stated predator is goneCorrect answer

Explanation

The snails lose the only predator this web assigns to them, so fewer snails are eaten and their numbers rise. The choice in which the small fish eat the snails fails because the web lists the small fish as eating algae only.

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Question 24: In this model food web the only feeding links are these:… · Food Webs and Energy Flow · Questena