Seeds stored before a long drought and seeds collected after many generations of drought are grown under identical, well-watered conditions. Plants from the later seeds have consistently smaller leaves. Controlled breeding tests show that plants from the two seed samples can produce fertile offspring together.
Which conclusion is best supported by both results?
Inherited leaf size has probably changed, but formation of separate species has not been demonstrated.
Inherited leaf size has probably changed, and formation of separate species has therefore been demonstrated.
Leaf size differs only because of current watering, but formation of separate species has not been demonstrated.
Leaf size differs only because of current watering, and formation of separate species has therefore been demonstrated.
44 exam-style questions on AQA GCSE Biology 6.2 Variation and evolution, covering 6.2.1 Variation, 6.2.2 Evolution, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, and 6.2.5 Cloning. Each one has a worked solution and a mark scheme showing where the marks go.