Two groups of birds look very similar. Scientists want to find out whether the two groups belong to the same species. Which evidence would show that they are different species?
The two groups have different songs and build nests in different places.
When the two groups breed together, the offspring produced are infertile.
The two groups have some differences in the base sequence of their DNA.
When the two groups breed together, the offspring look unlike either parent.
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.