Only Rabbits

The model may suggest what would happen if there were only rabbits, and no foxes, on the island.

Observe the predictions of the model for values in these ranges:

Initial # rabbits (R) between 50 and 200
Initial # foxes (F) equal 0
Rabbit birth rate (B) between .04 and .07
Fox death rate (D) between .04 and .07

Question 10: In the model, what do you observe when there are no foxes present?
The model predicts that in the situation in which no foxes are present the rabbit population would increase rapidly.

When there are no foxes present there is a significantly steep increase in the rabbit population in a brief period of time. The population will not climax and begin to come down until there have been foxes present for some time.

Question 11: Does this prediction make sense for a real system? Why or why not?
This prediction does not make sense for a real system. The rabbit population under these conditions would eventually reach an upper extreme, in which the proper resources necessary to sustain the rate of growth wouldn't be availible anymore. The rabbit population would grow within the limits of the islands resources.

The prediction provides a good hypothetical look at how populations will change over time, but this does not give us a good example for a real system. The assumptions made at the begining of this project do not follow the natural order of things in the wild.

This prediction does make sense although the situation is not realistic. However, if it was real, it makes sense that the rabits would continue to reproduce and grow in population until another force caused their population to decrease. This force would have to be foxes eating them in this situation. This is what the graph eventually depicts.

  • The island furnishes more than enough food to feed the rabbits.
  • The only way the rabbits die is being eaten by foxes.
  • The foxes only eat rabbits
  • The foxes die only of natural causes.

NOTE: Until April 17, please answer only one of the unanswered research questions. If you have an original contribution to make on a question someone else already has answered, you may include it at any time.

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