Purpose: How did the interstate affect the predator and prey populations?
State standard : 6b
6.
Stability in an ecosystem is a balance between competing effects. As a basis for understanding this concept:
6b.
Students know how to analyze changes in an ecosystem resulting from changes in climate, human activity, introduction of nonnative species, or changes in population size.
Background : The James Hyde farm has not had people living on it since June of 1971. An interstate highway was put through the middle of the farm. Now there are only 100 acres of land left on the farm. April of 1979, two biologists wanted to find out how the fox and rabbit populations were changing on the farm. They counted rabbits by trapping and then releasing them. They counted foxes by looking for them with field glasses because the foxes would not go near the traps. They trapped and released 23 rabbits. They saw 2 foxes.
Materials: red beans paper bag white beans red and blue pencils
Procedure:
1. Read the background section about the animals on and around the abandoned James Hyde farm.
2. Put 92 red beans and 8 white beans into a paper bag. Assume red beans are rabbits and white beans are foxes. From the above report you learned that 23 rabbits and 2 foxes were counted in April of 1979 (23 x 4
= 92; 2 x 4 = 8).
3. Shake the beans in the bag. Pick a bean without looking. Put a mark in the April 1979 column of Table
1. If you picked a white bean, mark in the fox column. If you picked a red bean, mark in the rabbit column.
4. Return the bean to the bag . Repeat the picking, returning the bean each time . Record a total of 25 beans. Total your results. These results show whether you would have obtained the same results as the two biologists in April 1979.
5. Now sample the populations after you change them as they changed between 1979 and 1983. Before you do each sampling, check the Population Change chart. If a changed occurred in the population at that time, change the beans in the bag as indicated in the chart.
6. After you change the population as in the chart, repeat the sampling you did for the April 1979 data (one bean at a time, returning the bean after each use until you have sampled 25 beans). Record your marks in your Data Table and total them after 25 beans. Then check the Population Change chart to see if you should change the beans before the next sampling.
7. Complete the sampling until your Data Table is completed through October 1983.
8. Construct a graph, similar to the one below, to show the data you gathered. Color the columns, use red for the rabbits, use blue for the foxes. The first column is done for you as an example. It is from the data the two biologists found in April 1979.

Data:
Chart 1: Population Change
Date of Change
October 1979
October 1980
April 1980
April 1981
October 1981
April 1982
October 1982
Rabbit Population
Remove 10 brown beans. Many rabbits died because winter was harsh and food was scarce.
Add 15 brown beans. Rabbits moved in from another area, food was plentiful.
No change in population.
Remove 8 brown beans. Many rabbits died from disease.
Add 12 brown beans. Early warm weather in spring caused rabbits to have young early.
No change in population.
Remove 14 brown beans. Foxes ate more rabbits because the mice population decreased.
No change in population.
No change in population.
Fox Population
Add 2 white beans. Foxes found pheasants for food. Thus, fox number increased.
Add 2 white beans. Foxes had larger litters than usual.
No change in population.
Remove 3 white beans. Some foxes left the area because of lack of food.
Remove 4 white beans. Hunters killed many pheasants. Rabbit numbers were down from the disease. Thus, foxes had less food.
Add 8 white beans. Foxes moved in from another area. Mice and rabbits were plentiful.
Remove 2 white beans. Hunters shot some of the foxes.
No change in population.
No change in population.
Table 1
April 1983
October 1983
Date
April 1979
October 1979
April 1980
October 1980
April 1981
October 1981
April 1982
October 1982
April 1983
October 1983
Marks
Rabbits
Totals Marks
Foxes
Totals

Make the graph as large as possible.
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Date
Conclusions:
Rabbit Fox
(color RED) (color BLUE)
1. How many acres of land is left of the James Hyde farm?
2. What do the words predator and prey mean?
3. List three factors that caused a decrease in the rabbit population and two factors that caused an increase in the rabbit population. (refer to Chart 1)
4. List three factors that caused a decrease in the fox population and three factors that caused an increase in the fox population. (refer to Chart 1)
5. How did the presence of pheasants and mice affect the fox population? (refer to Chart 1)
6. What will happen to the rabbits when there is a decrease in the mouse or pheasant population?
7. When is the last time that people lived on the James Hyde farm?