A species of annual plant reproduces using seeds. Inherited alleles cause some plants to flower early and other plants to flower late.
In one year, rainfall stopped before many of the late-flowering plants had produced seeds. The table shows the results.
| Flowering characteristic | Number of plants at the start | Number of plants that produced seeds | Mean number of seeds produced by each plant that produced seeds |
|---|---|---|---|
| Early flowering | 80 | 60 | 24 |
| Late flowering | 120 | 30 | 36 |
Every seed has the same chance of growing into a plant in the next generation.
Calculate the mean number of seeds produced per plant present at the start for each flowering characteristic.
Use your answers to part (a) to explain which allele is likely to become more common if this rainfall pattern occurs for many generations.
The rainfall pattern then changes for six generations. Rainfall continues until after all the plants have flowered.
A trial under these conditions gives the following results.
| Flowering characteristic | Mean number of seeds produced per plant present at the start |
|---|---|
| Early flowering | 14 |
| Late flowering | 22 |
Predict and explain how the proportion of the late-flowering allele after the six generations is likely to compare with its proportion immediately before the rainfall pattern changed.
71 exam-style questions on AQA GCSE Biology 6.3 The development of understanding of genetics and evolution, covering 6.3.1 Theory of evolution, 6.3.2 Speciation, 6.3.3 The understanding of genetics, 6.3.4 Evidence for evolution, 6.3.5 Fossils, 6.3.6 Extinction, and 6.3.7 Resistant bacteria. Each one has a worked solution and a mark scheme showing where the marks go.