Name:___________________________________________

**Objective:** Students will simulate predator prey interactions using cards. The number of predator and prey in their “ecosystem” will be recorded and graphed which will show a predator prey cycle in an ecosystem.

**Materials** (Prepared in advance)
Each group will receive 200 small squares cut from index cards (approximately
1 inch squared) -- The small squares represent the prey population.

Each group will receive 50 large squares cut from index cards (cut index cards in half) -- The large squares represent the predator population. Each group will receive a data table (prepared) and blank graph paper to graph the data.

**It is possible to substitute other materials to represent prey and predators, such as beans, paper plates, foam squares, pennies..etc**

Your lab table or desk will represent your ecosystem (Please clear all objects, such as purses and backpacks)

1. Place 3 prey; on your table.

2. Toss 1 predator onto the table (evenly dispersed) and attempt to make the
card touch as many prey; as possible. In order to survive, the predator
must capture at least 3 prey. It will be impossible for your predator to survive
at this point.

4. The prey population doubles each generation. Count how many prey (small squares)
you have left on your table, double that number and add prey cards to the table.
Record the number in the data table under the 2nd generation “number of prey staring”. (It should be 2x the number you have under the “hares remaining”
for generation 1)

5. Your predator died during the first round, but that’s okay, a new predator moves in for the second round. Put a 1 in the “number of predators” for generation 2 to represent the new arrival. Repeat the tossing procedure and record your data for the second generation.

6. Again, number or prey doubles, if your predator didn’t “capture”
3 prey, it died. But a new one moves in for the next round. Keep going, adding
to the number of prey each round.

7. Eventually your predator will be able to capture enough prey to survive.
Guess what happens? The number of predators double. Add to your predator population
by adding predator cards. Now when you toss your predators, you will be tossing
more than one. Don’t forget to remove any “captured” prey.

8. Continue to record the data through 20 generations.

Construct a graph. On the X-axis, put generations 1 through 20, on the Y-axis you will have the population numbers for each generation (number of predators, number of prey). Use one line for the predator and one line for the prey to graph the data.

GENERATIONS | ||||||||||||||||||||

1st | 2nd | 3rd | 4th | 5th | 6th | 7th | 8th | 9th | 10th | 11th | 12th | 13th | 14th | 15th | 16th | 17th | 18th | 19th | 20th | |

# of Predators Starting | ||||||||||||||||||||

# of Prey Starting | ||||||||||||||||||||

# of Predators Remaining | ||||||||||||||||||||

# of Prey Remaining |

Analysis

1. Describe what happens to the predator and the prey population as time goes by.

2. Make a prediction about what would happen to your prey population if a new predator is added to the system.

3. Explain how this simulation models a real ecosystem.

*Turn in your data table, graph and analysis*