Modeling Predation




BIO326 : Predation/Competition : Predation : Modeling Predation

Exercise: Modeling Predation

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DUE: 17-Mar-2000. Work sent after this date will receive a grade of zero.

1. Go to the Population Dynamics Models site at Leiden University in the Netherlands.

a) Choose the Lotka-Volterra predator-prey model. What are the values for the initial predator and prey densities, attack rate, conversion efficiency, mortality rate, and rate of increase? Initial conditions.

b) The model will run with these initial conditions when the site loads. Describe the time series of the two populations. Were the cycles synchronized (cf. pg 453)? Explain.

c) Describe the phase plane (graph with predator on one axis and prey on the other). What do the population trajectories show?

d) What are the equilibrium sizes of the prey and predator populations, respectively (cf. pg 460)? Note: the web site's attack rate is equal to the textbook's capture efficiency.

2. Double the intial prey density and run the model again. What changes occurred in the time series, in the equilibrium sizes of the two populations, and the phase plane? Double initial prey density.

3. What is a stable cycle, i.e., define it with respect to this predator-prey model.

4. Click to include the carrying capacity on the prey population and run the model. What changes occurred in the time series, in the equilibrium sizes of the two populations, and the phase plane? Include carrying capacity.

5. Models are used by scientists to focus on the essential aspects of a situation, and exclude the confusing details that are relatively unimportant. To what extent do the theoretical data from the Lotka-Volterra predator-prey model provide insight to the empirical data of Fig 20.5 on pg 453?

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E-mail Professor Gaud at William.Gaud@nau.edu
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