A species of wild cat and a species of small rodent lived only on one island. The climate of the island became much colder over a short period of time.
One food chain on the island was:
grass plants → rabbits → wild cats
Scientists collected the following data.
| Measurement | Before the climate changed | 10 years after the climate changed |
|---|---|---|
| Grass cover of the island | 78% | 24% |
| Number of rabbits | 1250 | 190 |
| Number of wild cats | 38 | 0 |
| Number of small rodents | 720 | 510 |
| Mean depth of the rodents' fur | 8.0 mm | 12.5 mm |
The small rodents produced several generations during the 10 years. Before the climate changed, there was variation in the depth of their fur. Rodents with deeper fur lost heat more slowly.
Explain how the changes shown could have caused the wild cat species to become extinct while the small rodent species survived.
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.