Student Sheet
Name_____________________________________
Title: Making a Food Web
Introduction: Every living thing needs a source of energy. Producers get light
energy from the sun, consumers get chemical energy from producers and
decomposers get chemical energy from dead producers or consumers. We call
all these feeding relationships a food web. You are part of a food web although
people don’t often hunt or gather their own food anymore. Our food comes in
grocery stores but, of course, at some point, it came from a plant or animal.
Many scientists worry that food webs in nature have been seriously altered by
people as we change the environment. In this activity you will make a food web
and investigate how it changes when an organism becomes extinct.
Materials Plant or animal card, string
Procedures:
1. Place your card around your neck so that others can read it. Listen as your
teacher begins the activity.
2. When the string comes to you, you must look around and see which
organisms do not yet have a hold of the string. Pick one and describe how it
depends on you. Hand them the string. Each person should hold the string so
that it can slide in their hand. Hold your fingers so they can pull on the string but
not grab it.
3. When the string has been around the room to everyone, gently pull the string
tight.
4. Listen as your teacher describes the loss of one of the organisms. That
person will loosen their hold on the string. If you can feel the string change its’
tension, raise your hand. After your teacher has counted the hands, write the
number down on your data table. Continue to hold the string and repeat the
process.
Data:
Organism
Type (producer, consumer,
decomposer)
Number affected by it’s loss
Analysis:
1. Which type of organisms seemed to affect the most others when it was lost in
the environment?
2. Why might that be true?
3. What types of energy are transferred through a food chain?
4. Fill in the food chain below for you. Think about what you had to eat the last
few hours.
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5. Write a paragraph that describes how the loss of a predator such as the wolf
or bear affects a food chain. Be sure to follow the chain down to the producer
level.