How (Rabbits and Wolves)

ASL	Rabbits and Wolves Help How Do I Use This Activity?

ASL	This Java applet requires a Java-capable browser. If you don't see the applet Java may not be functional in your browser or on your machine.

ASL	Controls and Output The "Start Simulation" 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 Simulation" button when pressed. There is also a "Step Simulation" button in the top-center of the applet that allows you to see the simulation step by step.

ASL	The "Pause Simulation" button allows you to pause the simulation and look at the current state of the grid. It becomes the "Resume Simulation" button when pressed.

ASL	The "Resume Simulation" button allows you to resume the simulation after it has been paused. It becomes the "Pause Simulation" button when pressed.

ASL	The "Reset Simulation" button sets up a new simulation based on the current parameters.

ASL	The "Forest Size" menu allows you to select the size of the forest.

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

ASL	The "Forest Border" menu allows 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.

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

ASL	In the Population Graph window, the "Display Tabular Data" button allows you to see the numbers for the last 250 iterations.

ASL	The "View Cumulative Stats" button allows you to view the population statistics for the current stage of the simulation.

ASL	The "View/Modify Parameters" button opens a window that allows you to modify various settings of the simulation.

ASL	The "View Simulation Key" button opens a window that displays a legend for the grid.

ASL	The general rules of this applet are: Two rabbits cannot occupy the same section of grass. Two wolves cannot occupy the same section of grass.

ASL	Each rabbit can only eat grass when he has not reached his maximum food capacity. (The maximum food capacity can be modified).

ASL	A wolf will not eat another rabbit if eating that rabbit will make him surpass his maximum food capacity. (The maximum food capacity can be modified).

ASL	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). A rabbit cannot reproduce if there is a wolf around her.

ASL	Rabbits and wolves can only move up, down, left, or right one space at a time.

ASL	Rabbits and wolves die if they get too old or if there is insufficient food. (Maximum age can be modified).

ASL	The grass growth rate is 1. (This growth rate can be modified).

ASL	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 (adjustable) default parameters: Maximum food capacity: 45 units Metabolism rate: 3 units/stage Reproduction age: 10 stages Probability of reproduction in a suitable environment: 50% Minimum food requirement to reproduce: 40 units Maximum age: 25 stages A rabbit gives a food value of 10 to the wolf that eats it.

ASL	Using this information, along with the general rules, the computer will determine where each rabbit will move, and whether it will live, die, or reproduce during each stage.

ASL	Wolves have the following (adjustable) default parameters: Maximum food capacity: 200 units Metabolism rate: 2 units/stage Reproduction age: 10 stages Probability of reproduction in a suitable environment: 50% Minimum food requirement to reproduce: 120 units Maximum age: 50 stages

ASL	Using this information, along with the general rules, the computer will determine where each wolf will move, and whether it will live, die, or reproduce during each stage.