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Food Chains

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

Here is a food chain:

Foodchain - cat, bird, caterpillar images Wikipedia (Creative Commons); Mullein image (c)



A wildcat will eat 3 birds every day. These three birds will eat 10 caterpillars each, every day, totaling 30 caterpillars. The 30 caterpillars will eat one small bush together every day.


a. The area that these animals live in currently has 500 small bushes: calculate the number of the other animals.



b. As you go up the food chain, the amount of energy available to the following predator decreases. For this food chain, the amount of energy available decreases by 25% for every level in the chain.

Calculate how much more energy the wildcat could obtain from becoming a vegetarian and eating the bush rather than from eating birds.



c. One year, a bacteria kills 5000 caterpillars. What effect will this have on the food chain?



d. What would happen to the cat, bird and caterpillar populations if the cats decided to become vegetarians and eat bushes to keep alive instead of starving?