Investigation Proposal
The Guiding Question:
How does the presence of a predator (Wolves) affect the population growth of rabbits?
Experimental Design:
 Independent Variable(s) – initial number of wolves (0, 5, 10, 15) and time (iterations)

Dependent Variable(s) – Population of rabbits (%capacity)

Measurements or Observations to be Recorded
o Iterations (time intervals)
o Rabbit Population (% Capacity)
o Wolf Population (% Capacity)
o Grass Population (% Capacity)
o Parameters that remain constant during the simulation:
 Initial Number of Rabbits = 20
 Initial Rabbit Food Level = 10
 Initial Wolf Food Level = 50
 Initial Grass Value = 20
 Forrest Size = Medium
 Forest Border = Toroid
Procedure
1. Access the online simulation called Rabbits and Wolves using the following website:
http://www.shodor.org/interactivate/activities/RabbitsAndWolves/ .
2. Set the parameters for the simulations as follows:
a. Above the Simulation Chart select from the drop-down menu:
i.
Forrest Size = Medium
ii.
Forest Border = Toroid
b. Click on the “View/Modify Parameters” button below the chart and establish
the following initial values:
i.
Initial Number of Rabbits = 20
ii.
Initial Number of Wolves = 0
iii.
Initial Wolf Food Level = 50
iv. Initial Grass Value = 20
3. Click on the “Start Simulation” button located above the Simulation Chart. Click on
the same button that now reads “Pause Simulation” to check the progress
periodically until at least 100 iterations have occurred.
4. Click on the “View Population Graph” button below the Simulation Chart to view the
change in population graph. The “Display Tabular Data” button in this window
provides a data table. Record data for the initial point and then for every interval of
Investigation Proposal
five iterations up to 100. (Ex., 0, 5, 10, 15, 20, 25…100) for the Rabbit, Wolf and
Grass populations.
5. Repeat steps 1-3 changing the initial number of wolves to 5.
6. Repeat steps 1-3 changing the initial number of wolves to 10.
7. Repeat steps 1-3 changing the initial number of wolves to 15.
Safety Precautions
Make sure that computer cords are plugged-into a power strip and not hanging from the
table or in walkways.
Analysis
Compare the rabbit population growth graphs over time for the varied wolf population.
The zero wolf population data provides the control or basis of comparison.
Group Member Names:
1. _________________________________
2. _________________________________
3. _________________________________
I approve of this investigation. ________________________________________________Date_________
Instructor’s Signature
Science