BIO 102 Lab 11: Food Webs
To submit, print this document, complete all lab activities and answer all
questions. Scan your lab pages using the free phone app AdobeScan, and upload
your PDF to Canvas.
If you have a disability that makes it difficult to complete this lab, please contact
your instructor. Please provide your instructor a copy of the Memorandum of
Accommodation (MOA) from NVCC Disability Support Services.
Objectives:


Examine trophic relationships in a community
Use a food web simulator to examine the effect of competition
and consumption on species in a community
Background:
In this lab, you will construct a food web and observe the effects of species
interactions. To prepare for this lab and to answer the follow-up questions, you will
need to be familiar with the types of interactions that exist between species in a
community. Read Chapter 41 (Ecological Communities) in Campbell Biology in
Focus, 3e, paying particular attention to Concepts 41.1 (both competition and
exploitation are important in this lab) and 41.2 (particularly the part on trophic
structure).
Materials:
Device with Internet access
Procedure:
1. Open the virtual lab located at https://www.learner.org/series/the-habitableplanet-a-systems-approach-to-environmental-science/ecology-lab/.
2. Read the overview.
3. Click on “Open Simulator” above the overview. The simulator should open in
another tab.
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4. In the initial tab, click on “The Producers”. Read the Challenge. Then Click
on “Step 1” for the Producers lesson.
5. Now go the simulator tab and conduct the simulation described in Step 1.
Record your thinking and data in the section below.
6. When you’ve completed Step 1 for The Producers, click on Step 2. The
conduct the simulation as before, recording your reasoning and data in the
section below.
7. When you’ve completed Step 2, read the For Your Consideration portion of
The Producers.
8. Now continue to work your way through the Lessons by completing Food
Web in the same way. You can change to the Food Web simulation from a
drop-down menu at the top of the simulator tab.
9. Record data and answers to questions in the sections that follow.
10. When you’re done, save this document with your data and upload to Canvas.
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Food Webs
Data Analysis and Synthesis
Questions:
Activity 1: The Producers
Lesson 1:
Step 1
Prediction: Starting
population
Prediction: Ending
population
Simulation: Starting
population
Simulation: Ending
population
Plant A
Plant B
1. What assumptions does this model make about co-dominance as well as the
general terrain of the ecosystem?
2. Do you find one producer to be dominant? If so, give a possible explanation.
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Lesson 1:
Step 2
Prediction: Starting
population
Prediction: Ending
population
Simulation: Starting
population
Simulation: Ending
population
Plant A
Plant B
Herbivore A
3. Does adding the herbivore establish a more equal field? If so, give a possible
explanation.
4. Is one producer still dominant over the other? If so, give a possible explanation.
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Activity 2: Food Web
Lesson 2:
Step 1
(X, , or )
Prediction
Simulation 1
Simulation 2
Plant A
Herbivore A
Omnivore A
Top Predator
5. List the species and relationships for your first (simplified) run.
6. State your prediction for your initial run.
7. Explain your reasoning for your prediction.
8. What differences were there between your prediction and the results of the
simulation?
9. What would happen to this imaginary community if the producers were to die
out?
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10. Did any of the species decrease in size? If so, give a possible explanation.
11. Did any of the species increase in size? If so, give a possible explanation.
12. List the species and relationships for your second (more realistic) run.
13. State your prediction for your second run.
14. Explain your reasoning for your prediction.
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Lesson 2:
Plant Plant Plant Herbivore Herbivore Herbivore Omnivore Omnivore Top
Step 2
A
B
C
A
B
C
A
B
Predator
(X, , or )
Prediction
Simulation 1
Simulation 2
Modifications
made
15. What differences were there between your prediction and the results of the
simulation?
16. Did any of the species decrease in size? If so, give a possible explanation.
17. What modifications did you make so that all the species survive? Explain your
reasoning for each modification.
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18. Which way does energy flow and how does eating an organism result in energy
transfer?
19. How does a natural ecosystem offer suggestions toward a more economical
and eco-friendly human model?
20. How do humans affect the greater food web? In this model, how could humans
who do not live in the ecosystem still manage to alter the flow of energy within
the web?
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