A population of lizards lives on an island with dark volcanic rock. Skin colour is inherited. Predatory birds hunt the lizards by sight.
Scientists record the numbers of dark and pale lizards at the start and after six generations.
| Time | Dark lizards | Pale lizards |
|---|---|---|
| Start | 45 | 255 |
| After six generations | 180 | 120 |
Calculate the percentage of dark lizards at each time. Explain the change in this percentage after six generations.
85 exam-style questions on Edexcel GCSE Biology 4.1 Evolution and natural selection, covering 4.1.1 Work of Darwin and Wallace and 4.1.2 Resistant organisms and evolution. Each one has a worked solution and a mark scheme showing where the marks go.