Ecosystems Interactive Simulation

Predator and prey populations are linked in a dynamic balance. When prey is plentiful food fuels predator growth; more predators then eat more prey, reducing the prey population, which in turn causes predator numbers to drop — and the cycle repeats. This Lotka-Volterra-type oscillation is a cornerstone of ecology. Students can change starting prey and starting predators and compare what happens. Use it for biology inquiry with Grades 4–5, Middle School, and High School on a projector or student device.

Standards: NGSS MS-LS2-1

• Why predator numbers always lag behind prey numbers (the 1.2 radian phase shift)
• What happens to the oscillation when you start with very few predators
• Why a large starting prey population eventually supports more predators
• How removing predators entirely affects the prey population over time
• Real-world examples: lynx-snowshoe hare, wolves-elk in Yellowstone

1. 1Predict how changing starting prey will affect the prey now, then test the prediction.
2. 2Use evidence from the interactive visual to explain the result.

Questions teachers ask