Two isolated populations of a bird have developed different beak sizes. When brought together, they mate and produce fertile offspring.
Which statement correctly evaluates whether speciation has occurred?
Different beaks suggest divergence, but fertile offspring do not support completed speciation.
Different beaks demonstrate speciation, but fertile offspring show that isolation was temporary.
Geographical isolation demonstrates speciation, but different beaks do not show inherited variation.
Geographical isolation prevents speciation, but fertile offspring show that variation has increased.
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.