Rabbits and Wolves Exploration Predator – Prey Simulation Activity http www shodor org interacti by drr10525

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									                                     Rabbits and Wolves Exploration
                                    Predator – Prey Simulation Activity
                           http://www.shodor.org/interactivate/activities/rabbits/index.html
Questions
In this applet allo ws the user to simu late how nature keeps its balance. Experiment with the settings in the Rabbits
and Wolves Activity to achieve sustainable populations.

Rabbits and Wolves Help
This activity allows the user to see how wolves and rabbits would behave in their natural setting as an examp le of
how nature keeps its balance. This Java applet requires a Java-capable bro wser. If you don’t see the applet Java, it
may not be functional in your browser or on your machine.

Controls and Output
The Start Simulat ion button on the top-left of the applet begins animating the interactions between the different
elements (rabbits, wolves, and the grass) of the grid. It becomes the Pause Simu lation button when pressed. There is
also a Step Simu lation button in the top-center of the applet that allows you to see the simulat ion step by step.


The Pause Simulat ion button allows you to pause the simulation and look at the current state of the grid. It becomes
the Resume Simu lation button when pressed.


The Resume Simulat ion button allows you to resume the simulation after it has been paused. It becomes the Pause
Simu lation button when pressed.


The Reset Simu lation button sets up a new simu lation based on the current parameters.


The Forest Size menu allo ws you to select the size of the forest.




The Speed scroll bar allows you to speed up and slow down the rate at which the applets displays the simulation.

The Forest Border menu allo ws you to choose between toroid and island. Toroid allows the rabbits to move off the
screen on one edge and wind up on the opposite edge of the forest. Island does not allow them to move this way.




The View Population Graph button opens a window that displays a graph of the number of rabbits, wo lves, and
grass per iteration.

In the Population Graph window there is the Display Tabular Data button that allows you to see the numbers for the
last 250 iterations.


The View Cu mu lative Stats button allows you to view the population statistics for the current stage of the simu lation.


The View/Modify Parameters button opens a window that allows you to modify various settings of the simulation.
The View Simu lat ion Key button opens a window that displays a legend for the grid.


Rules and Default Parameters
          Two rabbits cannot occupy the same section of grass.
          Two wo lves cannot occupy the same section of grass.
          Each rabbit can only eat grass when he has not reached his maximu m food capacity. (The maximu m food
          capacity can be modified).
          A wolf will not eat a rabbit if the rabbit will make him surpass his maximu m food capacity. (The maximu m
          food capacity can be modified).
          Rabbits and wolves can only reproduce when they reach a certain age and have a sufficient amount of food.
          (The age of reproduction and amount of food required to reproduce can be modified).
          Rabbits and wolves can move in any direction (including diagonally ) one space at a time.
          Rabbits and wolves die if they get too old or if there is insufficient food. (Maximu m age can be modified).
          The grass growth rate is 1. (Th is growth rate can be modified).

The rules for the births and deaths of rabbits and wolves are a bit more detailed. Let ’s begin with rabbits which have
the following (ad justable) default parameters:
         Maximu m food capacity: 45 units
         Metabolism rate: 3 units/stage
         Reproduction age: 10 stages
         Probability of reproduction in a suitable environment: 50%
         Minimu m food requirement to reproduce: 40 units
         Maximu m age: 25 stages
         Rabbits give a food value of 10 to the wolves when eaten.
         Using this information, along with the general ru les, the computer will determine whether each rabbit will
         live, die, or reproduce during each stage.
Wolves have the following (adjustable) default parameters:
         Maximu m food capacity: 200 units
         Metabolism rate: 2 units/stage
         Reproduction age: 10 stages
         Probability of reproduction in a suitable environment: 50%
         Minimu m food requirement to reproduce: 120 units
         Maximu m age: 50 stages
Using this information, along with the general ru les, the computer will determine whether each wolf will live, die, or
reproduce at each stage.

APES Investigations Procedures
A. Default Simu lation
1. Select “View Population Graph” and drag it to the right side to maintain access to all the buttons.
2. Select “Start Simu lation.”
3. Stop the simu lation after ext inctions make it point less.
4. Record the number of peaks for each species & the stage at which any species went ext inct.

B.   Controlled Experiments - Change only 1
1.   Select “View/Modify Parameters.”
2.   Choose "View/Modify Rabbit Parameters" or " View/Modify Wolf Parameters."
3.   Change & record ONE & ONLY ONE parameter of your choice.
4.   Close the parameter window so that only the Population Graphs & Forest chart are v isible.
5.   Start Simu lation.
6.   Stop simulation after ext inctions make it pointless.
7.   Record the number of peaks for each species & the stage at which any species went ext inct.
8.   Repeat 1-7 for each trial until you achieve a sustainable system with no ext inctions.

C. Analysis
For each trial describe what difference the change made to the results.
                                     Rabbits and Wolves Exploration
                                  Predator – Prey Simulation Data Table

Trial                  Default       1      2      3     4      5         6   7   8   9
Rabbits                20
Maximum food           45 units
capacity:
Metabolism rate:       3
                       units/stage
Reproduction age:      10 stages
Probability of         50%
reproduction in a
suitable
environment:
Minimum food           40 units
requirement to
reproduce:
Maximum age:           25 stages
Rabbit food value to   10
the wolves when
eaten.
Wolves
Maximum food           200 units
capacity:
Metabolism rate:       2
                       units/stage
Reproduction age:      10 stages
Probability of         50%
reproduction in a
suitable
environment:
Minimum food      120 units
requirement to
reproduce:
Maximum age:      50 stages
Forest Size            Medium
Grass Peaks
Rabbit Peaks
Wolf Peaks
Grass Ext inction
Stage
Rabbit Ext inction
Stage
Wolf Ext inction
Stage
C. Analysis
For each trial describe what difference the change made to the results.
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