Predator Prey Group Exercise

I. Fill in the following table for rabbits using the equations from the text and the following assumptions :

P_Rn= P_R(n-1) + B_R *P_R(n-1)

Initial population of Rabbits (P_R0 ) =100

Birth Rate for Rabbits (B_R )= .75

Assume no death rate for rabbits

Table of Rabbit Populations

Year	Population PR	Initial Population PR0
0	100	_
1		100
2
3
4
5
6
7

Use Corco to enter the table values, the Year as the x values and Population as the y values.

Plot the values with a linear fit or equation, squared equation, exponential equation. Which fit is the best? Why?

Hand in a copy of the table and the graph of the best fit.

II. Fill in the following table for foxes using the equations from the text and the following assumptions :

P_Fn= P_F(n-1) - D_F *P_F(n-1)

Initial population of foxes (P_F0 ) =100

Death Rate for Foxes (D_F ) =.25
(Assume no birth rate for the Foxes)

Table of Fox Populations Year Population

Year	Population Foxes PF	Initial Population Foxes PF0
0	100
1		100
2
3
4
5
6
7

Use Corco to enter the Year as the x values and Population as the y values.

Plot the values with a linear fit or equation, squared equation, exponential equation. Which fit is the best? Why?

Hand in a copy of the table and the graph of the best fit.

III. Fill in the following table for foxes and rabbits using the equations from the text and the following assumptions :

P_Rn = P_R(n-1) + B_R *P_R(n-1) - A* P_F(n-1)* P_R(n-1)

A is the interaction constant between the foxes and the rabbits

Set A = .005

P_Fn = P_F(n-1) - D_F *P_F(n-1)+ A* P_F(n-1)* P_R(n-1)

Initial population of foxes = 100

Initial population of rabbits = 400

Birth rate for rabbits = .75

Death Rate for Foxes = .25

Assume no death rate for rabbits and no birth rate for the Foxes

Table of Fox Populations Year

Year	Fox Population	Initial Fox Population	Rabbit Population	Initial Rabbit Population
0	100		400
1		100		400
2
3
4
5
6
7

Plot the two populations on the same graph Year as the x values and Population of Rabbits and the Population of the Foxes each as the y values.

Hand in a copy of the table and the graph.

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This page is Copyright 1998 by J. Barry DeRoos. All Rights Reserved.
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Last Modified: Feb 25, 1999.