Who Eats Whom?
Objectives
 Distinguish between a food chain and a
food web.
 Explain the roles of the producers,
consumers, and decomposers.
 Understand the meanings of autotroph,
heterotroph, herbivore, carnivore, and
omnivore.
 Recognize the dependence of organisms
on one another in an ecosystem.
Standards Addressed
Biology
6e. Students know a vital part of an
ecosystem is the stability of its producers and
consumers.
Investigation and Experimentation
Procedure
Part A: A Food Chain
1. Look at the organisms in the pictures on
the right.
a) Link the names of the organisms
together by the words “is eaten
by.”
b) Show the relationship between the
organisms as a linked word
diagram or chain.
c) Use arrows to show the direction in
which food energy moves in the
food chain you constructed in Part
(b)
d) Identify the procedure in the food
chain.
e) Identify the consumers in the food
chain
f) Which consumer is a herbivore
(feeds on plants)?
g) Which consumers are carnivores
(feed on other animals)?
h) What elements are missing from
this food chain?
Part B: A Food Web
1. Your teacher will provide you with a card that names an organism, what it does, what it eats, and
what it is eaten by. You will also be given a name tag with your organism’s name on it.
Read your card and attach your “name” tag where others can readily identify you.
2. Clear a large area in your classroom, or find another large open area in or near our school. Form
a large circle.
3. Obtain a big ball of string, about 3.5 m in length. Give the ball of string to one of the students.
4. The first student will say what organism he/she represents. Also, the student will indicate what
the organism eats and what it is eaten by. The ball of string is then directed to one of the
students who represents the predator or the prey
a) As the game progresses, what appears to be forming in the center of the circle?
5. Suppose one organism is removed from the circle. Your teacher will direct you which organism
will be removed.
a) What happens to the web that was created?
b) How does the removal of an organism impact on the other organisms in the circle?
6. Supposes that your circle has only a few organisms.
a) What would happen to the web in this case if one of the organisms were removed?
b) In which situation, a large or small “circle” of organisms, does the removal of an organism
have a greater impact on?
Analysis
1. What is the difference between a food web and a food chain?
2. Explain the role of producers and consumers.
3. How does the stability of any ecosystem depend on each one of its components?
4. Do you think non-native species would impact the structure of food webs and food chains? Explain
your reasoning.