Scientists classified three species of insect, P, Q and R. Species P and Q were placed in the same genus because both have broad, flattened bodies. Species R has a narrow body.
Scientists later compared 20 corresponding DNA regions from the three species.
| Species compared | Number of matching bases out of 24 000 |
|---|---|
| P and Q | 21 840 |
| P and R | 23 760 |
| Q and R | 21 720 |
Explain how the DNA evidence could lead scientists to change the classification of these insects.
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.