lesson
Populations change over generations
1 · Learn
Imagine a population of model insects with inherited light or dark colouring. On dark bark, predators may notice light insects more easily. If darker insects survive and reproduce more successfully, dark colouring can become more common over generations.
The light insects do not decide to turn dark. The model also simplifies reality: chance, other predators and environmental changes can matter. Evolution describes changes in populations across generations, not a deliberate improvement plan.
2 · Worked example
Model generation one has 5 dark and 5 light insects. A later generation has 8 dark and 2 light. This fits the prediction, but invented numbers illustrate rather than prove a real historical event.
3 · Your turn
Did the model show an individual light insect changing its inherited colour because it wanted to hide?
Check your answer
No. It described different representation of inherited variants across generations.
4 · Apply your learning
Use coloured paper counters on backgrounds to explore visibility; label the simulation's assumptions and limitations.
Adult guidance and safety
No live predators or insects needed. Avoid implying all evolutionary change has one cause or that darker always means fitter.
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Check a calculation · Year 5 onward
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