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Food Chains
Grade
Level K
- 4
Essential
Question 1 What is a food chain?
Objective
1 Students will relate various animals to each other in the
form of a food chain.
Materials
1 poster board, books or magazines about plants and animals,
pictures of plants and animals, glue or tape, and thread or string
(optional)
Approach
1 Display a large piece of poster board in the classroom, then
present the following: Most living things are predators. That means
they eat other living things. The living things a predator eats
are called its prey.
Each
week, ask the students to choose one living thing to study. Instruct
them to place a picture of that plant or animal on the poster board.
Ask them to find out what it eats, as well as what eats it. Do not
remove the pictures from the poster board. Over the course of the
year (or as long as you wish to continue this activity), ask the
students to discuss the predator-prey relationships among the living
things they have studied. How is each predator-prey relationship
related to others? How do these relationships form a chain that
links many living things together?
Reflection
1 Students can apply their knowledge of food chains to create
a food web. They can display the predator-prey relationships among
the living things pictured on the poster board by connecting the
appropriate pictures with thread or string. Ask them to imagine
one of the animals was extinct. Then ask them to explain how that
would affect all of the other animals. They can trace the string
to find all of the animals affected by the death of one animal.
Essential
Question 2 Can animals protect themselves from being caught
by predators?
Objective
2 Students will learn the concept of predator-prey relationships,
including ways organisms camouflage or hide themselves to avoid
becoming prey.
Materials
thirty short pieces of red yarn (or thirty red toothpicks), thirty
short pieces of green yarn (or thirty green toothpicks), large,
green area (carpet, blanket, grass, etc.), timer or stopwatch, paper,
pencil, graph paper (optional), and crayons (optional)
Approach
2
Cut thirty short pieces of red yarn and thirty short pieces
of green yarn. (Note: Instead of yarn, you can use sixty toothpicks
— dye thirty of them red and thirty of them green.) Spread
all sixty pieces of yarn (or toothpicks) over a large, green area.
Present the following to your students: Pretend the pieces of yarn
(or toothpicks) are caterpillars crawling on the grass. Pretend
you are a bird. You are a predator. The caterpillars are your prey.
You need to catch the caterpillars to survive. Each of you has one
minute to hunt for "caterpillars."
Allow
each student, one at a time, one minute to collect as many pieces
of yarn (or toothpicks) as he or she can. Count the number of red
"caterpillars" collected. Count the number of green "caterpillars"
collected. Record this information. Return all of the caterpillars
to the green area so the next student can take a turn catching "caterpillars."
How
many red "caterpillars" did all of the "birds"
catch? How many green "caterpillars" did all of the "birds"
catch? Older students may graph the results. Did the "birds"
catch equal numbers of red and green "caterpillars?" Did
the "birds" catch more "caterpillars" of one
color than the other? Why? Most likely, they caught more red "caterpillars"
than green ones. If this is the case, ask the students if they can
explain why. They will probably say the red ones were easier to
see in the "grass" than the green ones. Explain to them
that being green is an evolutionary trait that some caterpillars
have developed. This means that over very long periods of time,
green caterpillars have survived attacks from predators. The surviving
green caterpillars have gone on to produce more green caterpillars.
Reflection
2 What are some other animals that use their coloring to hide
from predators? Are there other ways that animals protect themselves?
Students can write a report on or draw a picture of an animal protecting
itself from a predator.
Illustration
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