A population of plants contains inherited variation in root length. Scientists placed 100 plants of each root length in dry conditions and another 100 plants of each root length in wet conditions. The table shows how many plants survived.
| Root length | Survived in dry conditions (out of 100) | Survived in wet conditions (out of 100) |
|---|---|---|
| Short | 25 | 72 |
| Long | 68 | 38 |
Calculate the percentage increase in the number of short-rooted plants that survived in wet conditions compared with dry conditions. Give your answer to the nearest whole number.
Using the data, explain which alleles are likely to become more common in each environment after many generations.
Suggest why plants with long roots may still be present in a population after many generations in wet conditions.
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.