Tools of the Simulator
Simulator Controls

- Reset Button
- Return to Day 0.
- Pause Button
- Interrupt a Run.
- Step
- Advance the simulator one day.
- Run
- Run the simulator to day 100. After day 100, run to the next hundred.
Food Web Controller
This shows the species in the food web and which
eats which. There are four levels in the food web: Plants (Producers),
Herbivores, Omnivores, and Top Predator. Each species rectangle is a button
that controls whether that species is included and, if it's an animal, what it eats.

Connecting Lines
The connection between two species means that one of the species (the one
higher in the web) feeds on the other. One species may eat
several others, or none.
- Plants
- These are the available producers for your simulated ecosystem.
In the picture above, only Plant A is turned on. Click any plant button to
turn it on or off, to include or exclude it from the simulation.
- Animals
- The animal species survive by eating one or more other species on the food web. When
you click
an animal button, a menu pops up asking you to select what it eats. Animals are
added to the ecosystem by eating another available species.
Herbivores
eat only plants. Omnivores can eat plants or herbivores, or each other. The Top
Predator can eat any other animal, but not plants.

- In the picture above, we clicked the Top Predator button. At the moment,
only HerbivoreA and OmnivoreA are
available for Top Predator to eat. It is currently eating OmnivoreA, shown
by the connection icon to the left. This is a toggle item—selecting OmnivoreA now
would turn it off, so that the predator stops eating OmnivoreA. In this menu, you could:
- Select HerbivoreA, to set Top Predator to eat both animals.
- Select OmnivoreA to stop eating it. This would have the side effect of turning
Top Predator off, because OmnivoreA is currently its only food.
- Select Close (or click outside the menu)
to close the menu without making any changes.
-
To make the Top Predator eat HerbivoreB, you would first
have to click HerbivoreB's button on the Food Web diagram and give it something to eat.
After that, if you clicked Top Predator again, the dialog shown above would include HerbivoreB
as an active option for Top Predator to eat.
- All On button
- Shortcut to turn on all species and all available connections.
- All Off button
- Shortcut to remove all species and all connections.
- Presets button
- Restores current Lesson's default foodweb settings.
Population by Species Graph

This graph shows the simulator progress over time. The y-axis is population
and the x-axis is the day. A line appears on the graph for each species
active in the simulation. The picture above ran the "All On" foodweb.
You can mouse over (or tap) a point on a line to get
a tooltip giving the line's value at that point. On the graph legend, you can
click a line's name to turn the line on or off. The legend may be
omitted on small screens.
Field Animation

The field animation shows the food web playing out in the field. Plant species
are shown by colored squares covering the field. The colors match the button
colors on the food web, or grey for bare ground, if plant populations are low.
Animals are shown on the field with icons, matching their icons on the food web.