Scientists sampled a population of fruit flies over four generations. They recorded the percentage of flies carrying allele R.
| Generation | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| Percentage of flies carrying allele R | 28 | 44 | 39 | 52 |
Which conclusion is supported by the data?
The percentage carrying allele R fell between generations 2 and 3, and was lower in generation 3 than in generation 1.
The percentage carrying allele R fell between generations 2 and 3, but was higher in generation 4 than in generation 1.
A mutation in some flies caused the percentage carrying allele R to fall between generations 2 and 3.
The number of flies carrying allele R in the population was greatest in generation 4.
122 exam-style questions on OCR GCSE Biology 5.2 Natural selection and evolution, covering 5.2.1 Genetic variation within a population, 5.2.2 Developments in classification systems, 5.2.3 How evolution occurs through natural selection, 5.2.4 Evolution as change over time, 5.2.5 Evidence for evolution, and 5.2.6 Darwin and Wallace. Each one has a worked solution and a mark scheme showing where the marks go.