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# Predator-Prey Simulation

## Objective:

To investigate how populations are affected by predator-prey relationships over multiple generations. Rubric

## Materials:

(1) lynx (6cm x 6cm square), 200 rabbits (2cm x 2cm square), 1 sheet of green paper (43 x 28 cm), Data Sheet, Graph Paper, Ruler, Pen or Pencil

## Procedures:

- Start with groups of 4 people: 1 data recorder, 1 lynx manager, 2 rabbit managers.
- The meadow is the playing field. Keep all animals within the boundaries of the meadow.
- Start the game with 3 rabbits evenly spaced in the meadow and 1 lynx.
- To play a lynx, you must toss the lynx from outside the meadow boundaries.
- All animals that are removed from the playing field are returned to the reserve pile.
- Rabbit Managers:
- Start with 3 rabbits evenly distributed on the playing field. If a rabbit card is touched by a tossed lynx card, the rabbit dies and is removed from the meadow. Return the rabbit to the reserve pile.
- After all lynx have been tossed for the round, the remaining rabbits reproduce and are doubled. (i.e. if 4 rabbits remain, add 4 more rabbits).
- Be sure to evenly distribute the rabbits over the meadow
- The meadow has a carrying capacity of 200 rabbits. If the rabbit population doubles over 200 animals, the rabbits over 200 die of starvation. You can only have a maximum of 200 rabbits at one time.
- If all rabbits die in a round, begin the next round with 3 rabbits that have migrated in from another area.

- Lynx Managers:
- Start the game with 1 lynx. Toss the lynx into the playing field. If the lynx lands on a rabbit, the rabbit is considered eaten. Remove the rabbit from the playing field. Use the following table for the requirements of the lynx’s survival.
Rabbits Caught Action Taken 0-2 Lynx Dies, new lynx migrates into area to start the next round 3-5 The lynx survives for the next round 6-8 The lynx reproduces 1 offspring, use 2 lynx in the next round 9-11 The lynx reproduces 2 offspring 12-14 The lynx reproduces 3 offspring 15-17 The lynx reproduces 4 offspring For every 3 rabbits and so on The lynx reproduces an additional offspring - When you have more than 1 lynx playing at a time, toss the same card over and over until all lynx have been represented. Remove rabbits eaten after each toss.
- If the lynx catches fewer than 3 rabbits, the lynx dies.
- If all lynx die in a round, then begin the next round with 1 lynx that has migrated in from another area.

- Start the game with 1 lynx. Toss the lynx into the playing field. If the lynx lands on a rabbit, the rabbit is considered eaten. Remove the rabbit from the playing field. Use the following table for the requirements of the lynx’s survival.

## Data:

- Record all data after each round until you have completed 25 rounds. To fill out the chart:
- For Generation 1, start with 3 rabbits in the 1st column, 1 lynx in the 2nd column. After tossing the lynx into the meadow, record how many rabbits were eaten. In the following columns record the number of lynx that died, then the number of lynx that lived, any offspring of surviving lynx and the number of rabbits remaining.
- Double the number of rabbits remaining and place that number into the 1st column of Generation 2.
- Add surviving lynx to new baby lynx and record the number in the lynx column of generation 2
- Continue recording in this manner until all generations have been completed.

### Example:

Generation | Rabbits | Lynx | Rabbits Caught | Lynx Starved | Lynx Surviving | New Baby Lynx | Rabbits Left |
---|---|---|---|---|---|---|---|

1 | 3 | 1 | 1 | 1 | 0 | 0 | 2 |

2 | 4 | 1 |

## Questions:

- During the first round, it is probable that the lynx dies. How do you explain this?
- Why is it important to continue the game for 25 rounds?
- Explain why there is a maximum limit of 200 rabbits.

## Interpretations:

- Graph your data (line graph) using the number of individuals as the dependant variable and the number of generations as the independent variable. Place both lynx and rabbits on the same graph. Study your graph lines for the two populations.
- How are the lynx and rabbit populations related to each other? How do the sizes of each population affect one another?
- Under what modifications can both populations continue to exist indefinitely?
- What do you think would happen if you introduced an additional predator, such as a coyote that requires fewer rabbits to reproduce offspring?
- What would happen if you introduced another type of rabbit, one that could run faster and escape its predators? (In the game, you could toss a coin for each rabbit caught to see if the rabbit escapes)
- In the above question, which type of rabbit would predominate after many generations of predation?

## Applications:

- How does this simulation relate to the human population and its interaction with its environment? Are there any predator-prey relationships?
- What predator-prey relationships have you observed in your community?
- If a population biologist visited your classroom, what are some questions about the human population you could ask?

### Source:

Leonard, W.H. and Penick, J.E. 2003. Biology- A Community Context. Glencoe McGraw-Hill.

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## Predator-Prey Simulation Data Table

Generation | Rabbits | Lynx | Rabbits Caught | Lynx Starved | Lynx Surviving | New Baby Lynx | Rabbits Left |
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