NAME _ CLASS _ DATE

4 ECOLOGY4-2 Food Chains and Food Webs

How Are Organisms Related? Enrichment

The organisms illustrated below are all part of one food web. Identify theorganisms on the lines provided. Draw arrows to tie the organisms togetherin a food web. Then complete the chart by describing the food that eachorganism eats and placing check marks in the appropriate columns.

,~ ~

F Dadfor Organism I ProducerFirst-Order Second-Order I Third-Order

Name of Organism Consumer Consumer Consumer1. plants

2. grasshopper !i

3. millipede J

4. dung beetle' .. - --~ --. ;

-- s.-hawk·

6. lizard 1- ..-7. snake8. toadstool i

,

I

~ 9. mouseI 10. bacteria.. - ._- I I

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4 ECOLOGY4-3 Food Pyram ids

Passing Energy Along Review

Each sentence below is followed by a set of four choices for completing it.Decide which of the choices is best. Then write the letter of the correctchoice on the space at the left.

I. Plants use about % of tile energy they get from the sun. a) LOb) 50 c) 90d) 100............ .

2. As you move up the food pyramid energy becomes available. a) no b) lessc) slightly more d) much more

__ 3. The "loss" of energy as you move up the pyramid is known as the Law.a) Diminishing b) Ten Percent c) No Gain d) Ninety Percent

__ 4. The "lost" energy as you go up the food pyramid is used for . a) reproduc-tion b) heat c) respiration d) carrying on life activities

5. The organisms are on the bottom of the food pyramid. a) largest b) mostactive c) smallest d) most unusual

__ 6. There must be producers to supply the consumers in the world. a) fewerb) the same number c) a few more d) many more

Food for Thought Enrichment

Use the food pyramid illustrated here to answer the questions that fellow.1. What mass of producers is required to make one kilogram of food. for a person?

What mass of water fleas does it take to make one illograID of food forcod?

2. Which organisms are the producers of the pyramid?3. Which organisms are the first-order consumers? _

The second-order consumers? ---

. The third-order consumers?What order are people? .. _

4. It has been said that 85% of the energy moving up the pyramid is lost at each level. Wheremight it go?

5. What advantages might there be if people ate lower on the pyramid?

3(' 40

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5. Which level receives energy directly from the sun?

6. Which level represents a plant eater?

7. Which levEl has the most food energy available?8. Which level would best represent the snake in the diagram above?

9. Which levels represent predators?

A

B

c

D

Analyzing Interactions Among Or~d.nlsmsIn 1997,a community decided to get rid of the population of rattlesnakes inthe area. The graph below shows what happened to the populations of .rattlesnakes, birds, and rodents. (The rodents included animals such as mice,rats, and prairie dogs)

Populations of Rodents, Birds, and Rattlesnakes

/~ «>:~------- ~~.Rodents

BirdS~ ... ,'~ "'.

j~Rattlesnakes

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Year

Answer the following questions on a separate sheet of paper.

1. Did the bird populations appear to benefit from the elimination of therattlesnakes? How do you know?

2. Did the rodent populations appear to benefit from the elimination of therattlesnakes? How do you know?

3. "Vhatwas the main source of food for the rattlesnakes? How can you tell?4. Why do you think the bird populations decreased sharply afterthe

rattlesnakes were eliminated?5. Do you think it was a good idea for the community to eliminate the

rattlesnake population? Explain your answer.