A grasshopper species lives in a habitat containing gaps between rocks. Hind-leg length is controlled by inherited alleles.
Scientists carried out two investigations.
In Investigation 1, the scientists measured the hind-leg muscle mass of adult grasshoppers and their offspring. All offspring were raised on level ground.
| Adult treatment | Mean hind-leg muscle mass of adults in mg | Mean hind-leg muscle mass of offspring in mg |
|---|---|---|
| Kept on level ground | 48 | 31 |
| Required to jump across gaps | 62 | 32 |
In Investigation 2, the scientists released grasshoppers with different inherited hind-leg lengths into the habitat.
| Inherited hind-leg length | Percentage that survived and reproduced |
|---|---|
| Shorter | 24 |
| Longer | 72 |
Over five generations, the percentage of grasshoppers with longer hind legs increased from 30% to 68%.
Explain how the results challenge Lamarck's idea and support Darwin's theory of natural selection.
71 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.