The Wolf-Sheep Predation NetLogo model simulates the interactions between predator and prey within an ecosystem. These systems are looked at as being stable if these populations are able to maintain a relatively steady population over time, whereas an unstable system will result in the extinction in one or more of the populations.
There are two main variations to this model that you will be working with:
In the first variation, wolves and sheep wander randomly around the landscape, while the wolves look for sheep to prey on. Each step costs the wolves energy, and they must eat sheep in order to renew their energy. If wolves are unable to catch enough sheep, they will die. At each time interval both wolves and sheep have a fixed probability of reproducing, depending on the corresponding sliders.
The second variation includes grass (green) in addition to wolves and sheep. The behavior of the wolves is identical to the first variation, however this time the sheep must also eat grass in order to maintain their energy, if they don’t they will die. Grass that is eaten by sheep will regrow after a fixed amount of time depending on the grass regrowth time slider.
Basics of the model
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Set the GRASS? switch to ON to include grass in the model, or to OFF to only include wolves (red) and sheep (white).
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Use the default slider settings.
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Go ahead and hit the "set up" button.
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Answer the questions before hitting "go"
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Press the GO button to begin the simulation.
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Look at the monitors to see the current population sizes.
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On the top of the world view you will see the word “ticks” with a number next to it. Each tick represents a unit of time passing by.
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Look at the POPULATIONS plot to watch the populations fluctuate over time.
The behaviors of these organisms are influenced by changing the values of the green sliders. Go ahead and mess around with the model and sliders to get used to interacting with it.
