Lesson 3.4 - Food Webs

You have learned what a food chain means and how to draw one.  You may have thought that a food chain is too simple.  The great horned owl eats more than just grouse. 

How can you show all the things that the great horned owl eats as well as all that the other animals in the chain eat?  Individual food chains are not adequate to show this.  Can you put together many food chains into one diagram?  Yes you can! It is called a food web. 

Read Food Webs on page 244 to learn about food webs. Then, answer the following questions.

 

Question 1. Compare a food web to a food chain.

Question 2. What is a primary consumer?  Give an example of a primary consumer.

Question 3. What is a secondary consumer?  Give an example of a secondary consumer.

Question 4. What is a tertiary consumer?  Give an example of a tertiary consumer.

Question 5. Is it possible for a consumer to be more than one of primary, secondary, or tertiary?

Question 6. Answer question 1 of Check Your Understanding on page 244.

 

Check your answers with those that follow.

 

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. Compare a food web to a food chain.

A food web is a more complete model than a food chain in showing how energy passes through an ecosystem.  Food webs are more accurate than food chains because they show the organisms that feed on more than one food level.  Food webs are actually many food chains in one diagram.

Question 2. What is a primary consumer?  Give an example of a primary consumer.

A primary consumer is an organism that eats only producers.  The rabbit eats only plants.

Question 3. What is a secondary consumer?  Give an example of a secondary consumer.

A secondary consumer is an organism that feeds on primary consumers.  A weasel eats primary consumers such as mice and rabbits.

Question 4. What is a tertiary consumer?  Give an example of a tertiary consumer.

A tertiary consumer is an organism that feeds on secondary consumers.  A great horned owl eats secondary consumers such as bats and weasels.

Question 5. Is it possible for a consumer to be more than one of primary, secondary, or tertiary?

Yes, in fact, most consumers are more than one of these levels.  The mouse in figure 12.4 is shown to eat only plants, but mice will also eat insects.  Insects will also eat other insects, so this food web in figure 12.4 is oversimplified.

Question 6. Answer question 1 of Check Your Understanding on page 244.

The correct food chain is

seeds → sparrow → hawk

 


Now, do Assignment 12C.  Page forward to access the computer-scored assignment.