Ecosystem Lab: Predator, Prey, and Carrying Capacity
Run a predator-prey ecosystem, adjust food supply, birth rate, predation, and carrying capacity, then track population stability over time.
Biology · Grade 11
Balance a predator–prey ecosystem over time
Change food supply, prey birth rate, predation, and carrying capacity to see Lotka-Volterra population cycles stabilize, oscillate, or collapse.
Baseline: let the ecosystem run until it cycles. Record when prey and predators are near equal peaks. Note the time lag.
Crash test: reduce food supply to 0.20. Watch for prey collapse. Can you adjust predation rate to prevent extinction?
Boom scenario: set prey birth rate to 0.50 and predation to 0.008. Does prey overgraze? Record biodiversity index at peak.
Balanced cycle: prey and predators oscillate out of phase (predator peak follows prey peak). Biodiversity index 51% — stable coexistence.
Lab task
Create one balanced ecosystem and one collapse scenario. Record both and explain which variable changed the outcome most.
Observation rule
Prey growth depends on food and carrying capacity. Predator survival depends on prey encounters, so predator peaks usually follow prey peaks.
What to prove in this lab
- Explain how carrying capacity limits prey growth.
- Describe how predator and prey populations affect each other over time.
- Use graph evidence to compare stable and unstable ecosystem settings.