Scientists are investigating the evolutionary relationships between four species of freshwater shrimp. They sequence the same region of DNA from each species.
| Species | DNA base sequence |
|---|---|
| P | ACGTTATGATCC |
| Q | ACGCTATGATTC |
| R | TCGCTATGATTC |
| S | ACGCTACGATCA |
Which two species are most likely to share the most recent common ancestor?
species P and Q
species R and S
species Q and R
species P and S
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.