Food Chain Balance Simulator
Model a three-level food chain and see how populations rise and fall together; remove a link and watch the balance break.
Before you try
What if all the foxes disappeared? Would the rabbits be better off forever?
Try it out
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What happened?
Move a control to see what changes and why.
Only three living things are modelled, with nothing else eating or competing. In a real food web a change ripples much further than it does here.
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Try these ideas
- Set foxes to zero. What happens to rabbits and then to grass?
- Start with many foxes and few rabbits.
- Find settings where all three stay fairly steady.
Why it works
Energy flows along a food chain: grass (producer) feeds rabbits (herbivores) which feed foxes (predators). When rabbits increase, foxes have more food and increase too. Then they eat more rabbits, rabbit numbers fall, foxes starve, and the cycle repeats.
This simulator runs a simple predator–prey model (a classroom version of the Lotka–Volterra equations). Set the grass growth, starting rabbits and foxes and press run; the graph shows how each population changes over the seasons.
Check your understanding
Question 1 of 3
In the chain grass → rabbit → fox, which is the producer?
If all the foxes vanished, what would most likely happen first?
After the rabbit population booms, the fox population usually…
Explain it in your own words
What changed? Why did it happen? Where might you notice this in everyday life?
For parents & teachers
- Draw a food chain from your garden or a nearby park.
- Ask: what happens to a food chain if the grass is sprayed with a weedkiller?
- Why are there always fewer predators than prey?