BIO 102 Lab 8: 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. Given drawings are not required, you may also type your work and submit your answers as a .DOCX file.
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 run a computer-based simulation that will construct a food web and observe the effects of species interactions. To prepare for this lab and be able to answer the follow-up questions, you will need to be familiar with the interactions that exist between species in a community. Read Chapter 41 (Ecological Communities) in Campbell, Biology in Focus, 2e, paying particular attention to Concepts 41.1 (both competition and exploitation are important in this lab) and 41.2 (particularly the section on trophic structure).
Materials:
· Computer/device with Internet access for website listed below (this may require a flash adapter, if it does not run properly, switch web browsers)
Procedure:
1. Open the virtual lab located at https://www.learner.org/series/the-habitable-planet-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.
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 youve 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 youve 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 youre done, save this document with your data and upload to Canvas.
Food Webs
Data Analysis and Synthesis Questions:
Activity 1: The Producers
Lesson 1:
Step 1
Plant A
Plant B
Prediction: Starting population
Prediction: Ending population
Simulation: Starting population
Simulation: Ending population
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.
Lesson 1:
Step 2
Plant A
Plant B
Herbivore A
Prediction: Starting population
Prediction: Ending population
Simulation: Starting population
Simulation: Ending population
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.
Activity 2: Food Web
Lesson 2:
Step 1
(X, , or )
Plant A
Herbivore A
Omnivore A
Top Predator
Prediction
Simulation 1
Simulation 2
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?
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.
Lesson 2:
Step 2
(X, , or )
Plant A
Plant B
Plant C
Herbivore A
Herbivore B
Herbivore C
Omnivore A
Omnivore B
Top
Predator
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.
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?
BIO 102 Lab 8: Food Webs
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