Lab: Oh, What a Tangled Web We Weave!
CLASSROOM COPY
Background: Plants use light energy of the sun to make food, which is stored in the cells of the plant.
Plants are called producers because they make food. Some of the stored energy in the food plants make
is passed on to the animals that eat the plants. Plant-eating animals are called primary consumers.
Animals that eat other animals are called secondary consumers, tertiary, or quaternary consumers.
The pathway that food takes through an ecosystem is called a food chain. A food chain also shows the
movement of energy from plants to herbivores and then to carnivores. An example of a food chain can
be written: seeds  sparrow  hawk
Some of the food energy in the seeds moves to the sparrow that eats them. Some of the food energy then
moves to the hawk that eats the sparrow. Normally, only about 10% of the energy produced by the
“food” moves to become part of the consumer. Most of the other energy is used to keep the organism
alive and allow it to reproduce. (metabolism)
Because a hawk eats animals other than sparrows, you could make a food chain for each animal the hawk
eats. If all the food chains were connected, the result is a food web. A food web is a group of connected
food chains. A food web shows many energy relationships.
Goals: In this exercise, you will:
a. determine what different animals eat in several food chains.
b. build a food web that could exist in a given ecosystem.
c. identify how a food chain can be shown as a food pyramid.
Materials:
 Set of organism cards and arrows
Part A: Examining Food Chains
Start by assembling a food chain from your “food chain” envelope as an example. Use the white arrows
to show the flow of energy from primary producer to the consumers.
Now, study the food chains listed below. Complete the table on the next page by putting a checkmark or
“X” in the box if it is eaten by the animal listed on the left side of the table.
plant parts  land snail  mouse  raccoon
plant parts  sparrow  hawk
plant parts  rabbit  fox
plant parts  mouse  fox
plant parts  earthworm  robin  snake
plant parts  raccoon  fox
plant parts  rabbit  snake
plant parts  cricket  robin  fox
plant parts  earthworm  snake  hawk  fox
plant parts  rabbit  hawk
plant parts  small insects  mouse  owl
plant parts  rabbit  owl  fox
plant parts  cricket  mouse  hawk
plant parts  mouse  snake  owl
Name _________________________________________
Due Date :
Per._______
Living Things the Forest Animals Eat
Sparrow
Snake
Robin
Raccoon
Rabbit
Plants
Owl
Mouse
Land snail
Insects
(small)
Hawk
Earthworm
Cricket
Animals in a
Forest
Ecosystem
Date ___________
Cricket
Earthworm
Fox
Hawk
Small insects
Land snail
Mouse
Owl
Rabbit
Raccoon
Robin
Snake
Sparrow
Part B: Making a Food Web Use the information above to create a food web.
 The first arrow in any food chain (between producer and primary consumers) should be green.
 The second (between primary consumer and secondary consumers) should be blue.
 The third (between secondary and tertiary consumers) should be red
 The fourth level (between tertiary and quaternary consumers) should be orange.
 Label each organism in the food web as PP (primary producer), PC (primary consumer), SC
(secondary consumer), tertiary consumer (TC), and Quaternary Consumer (QC).
Review Terms: Fill in the blanks
Primary producers are the first producers of energy-rich compounds used by other organisms. They are
the first level of the food chain. These organisms are called
due to their ability to
make their own food. Autotrophs include
organisms, that use energy from the
sun to make their own food and
, that use energy from chemicasl to make their
own food. Consumers cannot make their own food, thus are called
, which
means “other”-feeding. Consumers are classified by the way they get energy.
eat plants and are always
consumers. Omnivores are primary
consumers and a higher level consumer and eat both
and
.
Organisms consuming only meat are
.
are animals that consume the
carcass of other animals already killed. The two last types of consumers include
,
such as bacteria and fungi that “feed” chemically by breaking down organic matter and
, such as earthworms that feed on detritus particles. They include types of mites, snails, shrimp,
and crabs.
Word bank – detritivores, plants and animals, decomposers, autotrophs, heterotrophs, herbivores, primary, carnivores,
scavengers, chemosynthesizers, photosynthetic
Post-lab Questions: RSQ
1. In this forest food web, what living organism are primary producers? Remember to RSQ
Example: In this forest wood web the only primary producer is
2. What is another name for a primary producer’s ability to make their own food?
3. What animal is the ONLY secondary consumer in this food web?
4. What type of consumers are organisms that are only secondary consumers?
5. What animals are secondary, tertiary and quaternary in this food web?
6. What type of consumers are organisms that are secondary consumer and tertiary (or quaternary)?
7. What are the organisms that are carnivores in this food web?
8. What is another name for secondary, tertiary, quaternary consumer’s necessity to consume other
organisms for their energy?
9. What would happen to the food web if the plant population decreased? Explain and provide two
examples.
10. Below place arrows in place for the effect of the removal of owls from the food web.
Foxes
Mice
Rabbits
Plants