One population of lizards lived on a single area of land. The sea level then rose and split the land into two islands. The figure shows the land before and after the sea level rose.
Figure: The distribution of one population of lizards before and after the sea level rose to split the land into two islands

The lizards on island P and the lizards on island Q are now two different species. Explain how speciation produced these two species.
Suggest one characteristic of the lizards that natural selection might favour on island Q but not on island P.
Suggest how scientists could test whether the lizards on the two islands are now two different species.
40 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.