Scientists investigate whether two populations, P and Q, of sexually reproducing ground beetles belong to the same species.
They carry out four breeding trials. The scientists then test whether each offspring can produce offspring when paired with a beetle known to be fertile.
Under the follow-up test conditions, any fertile offspring from the breeding trials would produce offspring.
| Female parent | Male parent | Offspring tested | Offspring that later produced offspring |
|---|---|---|---|
| P | P | 20 | 18 |
| Q | Q | 18 | 16 |
| P | Q | 15 | 0 |
| Q | P | 16 | 0 |
Calculate the percentage of offspring from the P female and P male cross that later produced offspring.
Use the results to explain the conclusion the scientists should make about whether P and Q are the same species.
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.