Topic 3 Activity 2: A Tool for Inquiry - BioQUEST

ASSIGNMENTS:

Readings

Read the EDM manual pages 19-30. The material on graphing is a review. The rest describes how to model food chains in EDM. Optional: You may wish to read the "3 P's Problem Posing, Problem Solving and Persuasion" document by John Jungck and Nils Petersen. Your Site Coordinator has a hard copy. This article provides additional perspective on the use of models and the teacher as a guide to learning, not the source of all information.

Hands-On

Remember to save all EDM models with an eight character name and the extension EDM (for example, testname.EDM).

You will learn to: add SUNFISH, BASS, and GAR to your model, (Gar is a voracious predator on sunfish. It is nota "fun" fish to catch, nor do people like to eat it. Build a model with gar.) add and explore the effects of a level consumer (fishermen), calibrate the model with multiple layers of consumers, and explore some envirornmental decision problems involving fishing, non-edible predators, and management policy.

Bring up or build another POND worksheet. Your POND should have POND LIFE, SUN, and a QUANTITY PLOTTER icons. Run it with a few different calibrations for sunlight. Confirm your understanding of the graphing tools. Follow the instructions on page 21. Add SUNFISH. Add labels to the DATA table (p. 22). Add a legend to the DATA table. Add BASS to the model. The bass are predators of the sunfish. Calibrate the BASS MODEL (p. 24-25). Follow the directions to display two graphs on the plotting window with two different scales. Experiment with adding small numbers of bass. How long does it take to reach equilibrium? Continue with the questions on pages 25-26. What is the carrying capacity of this pond? Measurements are all metric. Bass in EDM weigh about 1 kg each.

These moving images illustrate the new features being explored.

How do I: Add SUNFISH.? Adding BASS means selecting the BASS icon. Adding GAR likewise means selecting the GAR icon from the library. Add a FISHERMAN icon from the menu?

Calibrating models is an important feature of EDM. Without addition of another species, or a top level predator like humans, the model, and its real world counterpart, the pond, will reach a condition called steady state. The initial values of sunfish do not influence the values for populations at that final stage. By starting at equilibrium or steady state we can observe what the effects of new elements like sunfish, bass, fishermen, gar, or other predators will have on the pond ecosystem. Explore the "What If" scenarios at the bottom of page 28 of the EDM material. Begin thinking about postings or questions you may want to ask.

Reflection

While working with the materials take a few minutes to ask: 1. What tools were learned? 2. Where is the science?

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