Isle Royale

Ecosystems are often difficult to understand because they usually include interactions between a large number of species. Isle Royale is different. It is a relatively simple island ecosystem, located 24 km from the shore of Canada in Lake Superior.

While there are many types of small animals on the island, and almost 20 types of mammals, only two species of the mammals that live on the island are relatively large. These are the wolves and the moose. On this island, wolves are the only predator of moose, and moose are essentially the only food for wolves.

To understand nature, it helps to observe an ecosystem where human impact is limited. On Isle Royale, there are no towns and people do not hunt wolves or moose or cut the forest. It is a very rare place on the planet where wolves, their prey, and the plants that support the prey are all left unharvested by humans. Isle Royale is remarkable, because nature runs wild there.

Your challenge will be to build a scientific model that can more realistically simulate the interactions of wolves and moose on Isle Royale, in order to help make predictions about how these two populations may change over time. 

1. Scroll down the page and interact with the setup and go (play) button.
2. Drag blocks over to tell the wolf and sheep how to behave. Anytime you make changes click on the "recompile" button followed by setup and go (play).
3. Blocks can be used multiple times.
4. Blocks can be dragged to the trash to take them out of the code.
5. Your first challenge is to make the wolf move around the field.
6. Work on the other challenges found at the bottom of the page.

The poor defenseless sheep should be allowed to move as well. Let's see how we can make this a more realistic model. Start by setting up realistic movement for both wolf and sheep and then move on from there.

Challenges:

1. Wolves and sheep move around the field realistically.
2. Make the wolf appear to eat a sheep when it runs into one.
3. Make the sheep slowly multiply.

Now we will look at the computer code produced from your blocks.

Scroll down and click on the triangle next to "NetLogo Code" 

Drag some blocks over and look at the code that shows up in "NetLogo Code"

Answer the questions below.

Now that you have created a more realistic model of wolves and sheep, what can you do to make an extremely unrealistic model ?

Challenge:

Use any combinations of blocks below to make your own unrealistic world of wolves and sheep. Explain your process below.

We will transfer the code that you generated in NetTango to the new NetLogo model. This will give us the basic functions that you worked on before but allow us to make more direct changes.

1. Set up a model similar to the one you completed in the earlier lesson using NetTango. 

2. Scroll down to the full code and copy the code into the "NetLogo Code" section. Take a look at the animated gif for help.

3. Click the "NetLogo Code" button in the second model and paste the code there.

4. Click the recompile button on model 2 

5. Click setup and go in model 2.

6. Answer questions below.

3. After you paste the code, go ahead and click on the "recompile code".

4. Click the setup button.

Let's take a look at this ecosystem. How can we change the code to make it more similar to the model below it. This will allow us to a wider look at this ecosystem. Open the NetLogo code tab and make the changes need to transform your NetTango model into a model that shows interactions on much wider scale.

Challenge:

Change your model to more resemble the animation on the right, by making changes in the Code tab. As before always recompile after making your changes.

We have made the world larger and changed the agents and the world to more closely resemble the ecosystem of Isle Royale. It is still missing quite a bit of realism though. Lets see if we can fix that.

We have added several  useful tools to the model to make it easier to interact with the code.

Instead of changing the wolf and moose population sizes in the code, you can now use the sliders.

There is also now a graph that shows the population numbers from tick to tick.

Setup and Go!

*We will add some primitives here that students can add to their models to make them more realistic*

Now that you have created a realistic model of wolves and moose, what can you do to make this model extremely unrealistic? Explain your process below.