Food Chains and Food Webs
Name: _______________________________
Class: ___________
Outcomes Covered
4.1.1 Identify the roles of producers, consumers, and decomposers in a local ecosystem and describe both their
diversity and their interactions
4.2.1 Describe how matter is recycled in an ecosystem and evaluate potential applications of energy
transformations
4.2.2 Describe how energy is supplied to, and how it flows through, the structures and interactions in a natural
system, using charts, diagrams, and terminology
Instructions: In the spaces provided below please answer the following questions. Please ensure your
answers are fully completed and well written.
1.
For the following food chain, indicate the:
a) Consumer
b) Primary (1st) consumer
c) Secondary (2nd) consumer
d) Tertiary (3rd) consumer
e) Quarternary (4th) consumer
f)
Herbivore
g) First Carnivore
h) Top Carnivore
2. Complete each of the following food chains with an appropriate animal.
a) In a woodlot:
leaves → worm → ____________________________
b) In a pond:
algae → insect → ____________________________
c) In a forest:
grass → rabbit → ____________________________
3. Consider a common food chain in Ontario:
Sapling (young tree) → Deer → Wolf
a) If the deer population increases, what will happen to:
i. The sapling population?
ii. The wolf population?
b) The changes in the sapling and wolf population will cause a change in the number of deer. What
happens to the deer population as a result?
c) As a result of the change in (b) what will now happen to:
i. The sapling population?
ii. The wolf population?
Answers
a)
b)
c)
4.
The area of Ontario in which this food chain occurs contains other organisms such as grass,
mice, rabbits, hawks, frogs, snakes and insects. We can connect all these animals together in a
food web, as shown below.
Mouse
Sapling
Grass
Snake
Deer
Wolf
Rabbit
Hawk
Insect
Frog
The food web represents a more realistic situation. In the above food chain:
a) What are the two foods that the deer eats?
Answer
b) What does the wolf feed on?
Answer
c) Why is it advantageous for the deer and the wolf to have more than one food source?
Answer
d) Are there any omnivores in the above food web? If so name them.
Answer
e) The above food web contains 16 food chains. Identify 2 of them.
Answer
f)
If the number of rabbits were to increase, what would happen to each of the following
populations:
i. Grass
ii. Hawks
Answer
g) Will the changes in question (f) have any effect on the number of mice in the area? Explain.
Answer
5.
One of the most important organism omitted from our food chain and web is the decomposer.
a. What is the role of a decomposer?
b. Why are decomposers important?
Answer
6.
Consider the following food chain:
At each level (called trophic levels) of the food chain, energy (in the form of joules) is lost.
Approximately 90% of the energy consumed by the grasshopper is used in its day-to-day metabolism,
and only 10% can be passed on to the mouse who eats it.
Food chains rarely go beyond 5 trophic levels. Please explain why. Be certain to discuss energy transfer
in your answer.
Answer
7. Using the food chain on the previous page please answer the following questions:
a)
b)
c)
d)
e)
f)
g)
Identify all the producers.
Construct a food chain that has four trophic levels.
Identify three herbivores.
Identify three secondary consumers.
Identify all the omnivores (if any).
Identify any organisms that occupy more than one possible trophic level.
Explain what might happen to the fox and owl populations if a disease dramatically reduced the
mouse population.
Answers
a)
b)
c)
d)
e)
f)
g)
Marking Rubric
Questions
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