Questions:
1. In how many food chains do the following animals appear? (count the # of food chains in part B)
hawk ___4__ earthworm ___2__ fox __6___
owl ___3__ snake __4___ small insects__1__
2. In how many food chains do plants (parts) appear? __all(14)__
3. List the names of the living things in this forest ecosystem that are producers. Plant parts
4. List those things that are only primary consumers. Crickets, earthworms, small insects, land snails, rabbits, and sparrows.
5. What is another name for an animal that is only a primary consumer? Herbivore
6. List those things that are only secondary consumers. Foxes, Hawks, Owls, Robins, Snakes.
7. What is another name for an animal that is only a secondary consumer? Carnivore
8. List the consumers that eat both plants and animals. Mouse, raccoon
9. What is another name for an animal that eats both plants and animals? Omnivore
10. What would happen to the food web if all the plants were removed? Everything will die.
Explain your answer. Plants are the only organisms that can make their own food.
11. Describe how 3 animals might be affected if owls were removed from the food chain. Rabbit, mice , and snakes will probably increase since one of their predators is gone.
12. Draw three food chains showing producers and consumers that you might see in your backyard or on your way to school. (You may use words or drawings.)
grass → grasshopper → robin
nut → squirrel → cat
berry → bird → cat
(OR ANY OTHER VALID EXAMPLE)
13. Since only 10% of the energy produced by a level in a food chain is passed on to its predator, there have to be many more “prey” than “predators”. Draw a food pyramid of the first food chain listed in Part A. Remember that there are more producers than primary consumers, more primary consumers, and secondary consumers, etc.
raccoon
mouse
land snail
plant parts
14. If 2000 kcal of energy are available in the grass, how much energy would be available to the cow that eats the grass? To the human that eats the cow?
Assuming that all energy is used:
Since only 10% of the energy is available to the next level consumer – (.1)(2000 kcal) = 200 kcal of energy available to the cow. For the human (.1)(200 kcal) = 20 kcal available to the human. In other words, the human-only receives 1% of the original energy produced by the plant.
15. Which organism in this food web has the greatest influence on the ecosystem? Justify your answer.
This is a really tough one to answer. In reality, they are all equally important, and time should be spent going over all possibilities. Most students will guess plants since all life depends on the the energy produced by plants. The teacher should also point out that, if a top-level consumer is killed off, the organisms it eats will increase in population, which might mean that more grass will be eaten, etc. All attempts should be made to show the interdependence of organisms in an ecosystem and to show that they are, therefore, all important.
Food web and Livings Things the Forest Eat graph
