What is this simulation about?
You manage a population of island finches with three beak types: slender beaks that reach nectar, medium beaks that crack seeds, and heavy beaks that crush nuts. When a drought arrives and food sources change, which birds survive?
How to use it
- Drag the food mix dividers and watch the island respond in real time.
- Drag the orange markers on the timeline to set when the drought starts and ends.
- Press Run and watch the flock shift across generations.
- Data is sent to Tuva automatically when the run ends.
Things to try
- Start with mostly nectar. Which beak type dominates before the drought?
- Make a short drought vs a long drought — how does duration change the outcome?
- After recovery, does the flock adapt back quickly or stay heavy-beak dominant?
Standards
- MS-LS4-4 — Natural selection and adaptation of a population
- MS-LS4-6 — Mathematical representations of trait proportion changes
How the model works
Each generation, each bird's survival probability is a weighted sum of beak-food efficiency scores across all three food types. Survivors reproduce at a food-limited rate with the same beak type. Students set the environmental conditions, but the environment does the selecting.
Beak efficiency matrix
- Slender beak: nectar 90%, seeds 22%, nuts 4%
- Medium beak: nectar 38%, seeds 80%, nuts 28%
- Heavy beak: nectar 5%, seeds 28%, nuts 88%
Drought mechanics
Drag the timeline anchors to set drought start and end. Drought reduces nectar most (−95%), seeds substantially (−75%), and nuts only slightly (−10%). Recovery restores the original food mix so students can observe the population lag — the flock adapts slowly even after food returns.
Key discussion questions
- Were heavy-beak birds already present before the drought?
- Did the drought create heavy beaks, or reveal which birds already matched the new conditions?
- What would have to happen for slender beaks to return quickly after recovery?
Assumptions and simplifications
- Three discrete beak categories replace the continuous spectrum of real finch beaks.
- No migration, mutation, gene flow, or sexual selection is modeled.
- Food transitions ease over several animation frames so drought feels like a weather event.