Behavior Over Time

The model may suggest how the populations of rabbits and foxes will vary over time.

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

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

Question 1: What does the model predict about how the populations will vary over time?
Judging from the chart generated from the data, both the fox and the rabbit populations experience repeated periods of steep increase in population, followed by periods of steep decrease. Over time, this pattern of increase then decrease continues but each time the population is slightly larger than it was the time before. There is a lot of fluctuation in the numbers over time.

As we can see by the results from the chart, the fox and rabbit populations have massive increases in their respective populations. After the large increases we see that there is a huge fall off in the populations of both that reduce the number of both species. Eventually these large increases and decreases result in the population of both animals to be larger.

The model predicts that the populations of the ##red rabbits## rabbits and foxes will experience a steep increase followed by a steep decrease. The ##red rabbit## rabbit population will increase first and as it decreases the population — of — of foxes will begin to increase steeply and then decrease steeply. This pattern continues over and over. The only change is that the steep increases and steep decreases get bigger as time goes on.

Question 2: Do these predictions make sense? Assuming that the rabbits and foxes live together in an isolated location, such as an island, why might their populations behave like the model suggests? Or why not?

These predictions do make sense. Their populations behave as the model suggests because the foxes are dependant on the rabits. As a result, it makes sense that as the rabbit population increases, the fox population will increase, thus, following the rabbit population increase, because there are more sources to support the life of a larger population of foxes.

Yes, these predictions make sense because of how the model is set up. Also, we assume the predictions are accurate due to the fact there are no other animals for a) the foxes to eat or b) to eat the rabbits. The fox and rabbit population fluctuate due to the following:

  • Foxes (predators) eating the rabbits (prey)
  • Increase in number of Rabbits is due to the rapid birth rate
  • Increase in number of foxes is due to the abundance of rabbits(prey)
  • Decrease in foxes is due to the decrease of rabbits because of their consumption and also from natural causes
  • Decrease in foxes causes the rabbits to increase in numbers and start the model all over again

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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