Lab # _____: Forest and Cornfield Ecosystem Food Webs
Lab Skills: 13, 15, 23
Background: Organisms interact in many interesting ways within an ecosystem. Tracing
the flow of energy by drawing food webs can help you better understand how organisms
depend upon one another for survival.
In this investigation, you will construct and compare food webs for two very different
ecosystems – a forest and a cornfield. You will see that organisms that inhabit one of the
ecosystems have a much more complex food web than organisms living in the other. There are
advantages and disadvantages to calling either ecosystem home, however, the food webs that you construct will
provide evidence that one has much greater stability due to the complex pattern of connections between
organisms when displayed in a food web.
Hypothesis: We think that... (finish the hypothesis by stating whichever ecosystem you
and your lab partner think has a more complex food web.)
Procedure:
Part 1 – food web construction…
1. The table on page 3 of this lab contains two lists of organisms. One list
includes organisms from an oak-hickory forest ecosystem and the other includes organisms from a
cultivated cornfield. Carefully read the lists and in your mind, identify as many feeding relationships as
possible.
a. After thinking about the organisms’ feeding relationships you can use the information on page 4
to see if you were accurate in determining the organisms’ feeding relationships.
2. Select twelve (12) organisms from each ecosystem that you could use to create a food web and
cut them out of the page of pictures of organisms. You must include at least one plant, one animal,
and one decomposer for each food web.
a. Make sure to keep your piles separate so that cornfield organisms don’t end up in your forest
ecosystem and vice versa. If you want to use an organism but are unsure of what it eats, feel
free to find out about its food sources using a book for reference or simply refer to page 4 for a
general description of what eats what.
3. Construct a food web for the forest ecosystem on one side of a sheet of paper and a food web
for a cornfield on the other side. Discuss how the organisms should be arranged with your lab
partner prior to gluing anything to the paper.
4. Use markers or colored pencils to draw arrows showing the direction of energy flow through the
ecosystems. Remember that the arrow heads should always point away from the organisms being
eaten.
5. Make sure to label each diagram clearly – Forest Food Web or Cornfield Food Web.
Part 2 – making observations…
6. Label the feeding relationships of the organisms on your food webs. Every single organism
should be labeled as: Producer, Herbivore, Carnivore, Omnivore, Scavenger, or Decomposer.
7. Compare your food webs to those created by three of your classmates. Create a data box like the one
that follows on the top of page 2 and list a complete food chain (from producer to decomposer)
that you found to be noteworthy or interesting. Repeat this step for the lab reports of two more
classmates.
Food Webs Lab
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a. Use only as many spaces as you need. For example, if a food chain only has 3 levels, you
would only need to fill in 3 spaces.
 Student: ________________ Circle: Forest / Cornfield
____________ → ____________ → ____________ → ____________ → ____________ → ____________
 Student: ________________ Circle: Forest / Cornfield
____________ → ____________ → ____________ → ____________ → ____________ → ____________
 Student: ________________ Circle: Forest / Cornfield
____________ → ____________ → ____________ → ____________ → ____________ → ____________
8. Discuss with three students which ecosystem is more complex. Ask her or him why they feel the way
they do and record what you find out in the next data box that you should re-create in your lab
report.
 Student: ________________ Circle choice: Forest / Cornfield
Why does she/he feel this way? _______________________________________________________________
 Student: ________________ Circle choice: Forest / Cornfield
Why does she/he feel this way? _______________________________________________________________
 Student: ________________ Circle choice: Forest / Cornfield
Why does she/he feel this way? _______________________________________________________________
9. Staple everything together neatly.
Analysis:
1. Explain at least two ways the forest and cornfield food webs are different.
2. Name the producers in the forest ecosystem and the cornfield ecosystem.
3. Name the omnivores in the forest ecosystem.
4. Name the herbivores in the cornfield.
5. Suppose the producer population in each ecosystem entirely died out due to a new disease. What effect
would the loss of that population have on the organisms that eat the herbivores of each ecosystem?
6. Why are decomposers important to every food web in every ecosystem?
7. After analyzing your food webs and discussing with your classmates, which ecosystem do you conclude has
a more complex food web and resultantly would be considered to have greater stability? Explain why.
8. Why is stability in an ecosystem considered to be beneficial?
Food Webs Lab
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~ Organisms List for Forest and Cornfield Ecosystems ~
Select 12 for each food web!!! You must include at least 1 producer, 1 consumer, and
1 decomposer for each food web.
Forest Ecosystem
Producers
Consumers
Decomposers
Food Webs Lab
White oak
Aspen
Black oak
Apple
White pine
Blackberry
Gray birch
Dogwood
Beetle
Ant
Cornfield Ecosystem
Corn
Raccoon
Hawk
Chickadee
Snail
Corn snake
Crow
Termite
Snake
Groundhog
Deer
Moth
Spider
Field mouse
Cricket
Centipede
Cardinal
European corn borer moth
Woodpecker
Deer
Grasshopper
Fly
Black bear
Squirrel
Earthworm
Sparrow
Flycatcher
Vole
Owl
Mouse
Raccoon
Opossum
Mosquito
Chipmunk
Mushroom
Bacteria
Shelf fungus
Earthworm
Bacteria
Earthworm
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Feeding Relationships of Organisms Inhabiting Forest and Cornfield Ecosystems
Producers: make their own food using sunlight, carbon dioxide, and water
Corn
Acorn (from
Aspen
Apple
Blackberry
the oak trees)
Birch
White pine
Herbivores: eat plants only
Beetles
Leaves and fruit
Ants
Fruit
Earthworms
Rotting leaves and rotten fruit
Snail
Leaves and fruit
Termites
Wood from trees
Moth
Flowers of fruiting plants and corn
Centipede
Rotten wood
Cricket
Leaves and fruit
Grasshopper
Leaves
Fly
Leaves and fruit
Chickadee
Seeds
Cardinal
Fruit and seeds
Sparrow
Seeds
Squirrel
Acorns and seeds
Chipmunk
Seeds
Mouse
Seeds
Groundhog
Fruit, seeds, leaves
Deer
Fruit, acorns, leaves, corn
Carnivores: eat other consumers
Fly catcher
Insects
Spider
Smaller insects
Mosquito
Blood of mammals
Woodpecker
Insects
Hawk
Smaller birds, rodents, baby raccoons, baby opossums, snakes
Owl
Rodents
Snake
Rodents
Omnivores: eat plants and animals
Crow
Insects, earthworms, fruit, corn
Raccoon
Corn, apples, blackberries, insects
Opossum
Corn, apples, blackberries, insects
Vole
Corn, apples, blackberries, insects
Bear
Corn, apples, blackberries, insects, small mammals
Decomposers: break down the dead or decaying remains of other organisms, recycling nutrients in the
process
Mushrooms
Soil bacteria
Shelf fungus
Earthworms
Food Webs Lab
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