A population of plants has two inherited leaf types: leaves with a thin waxy layer and leaves with a thick waxy layer. Scientists grow 50 plants of each type under the same conditions and then expose them to a dry period. The table shows how many plants of each type survive the dry period and produce seeds.
| Leaf type | Number of plants at the start | Number that survive and produce seeds |
|---|---|---|
| Thin waxy layer | 50 | 12 |
| Thick waxy layer | 50 | 34 |
Explain how the proportion of plants with a thick waxy layer on their leaves could change over several 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.