A species of lizard lives only on one island. A predatory snake arrives on the island. Scientists survey the lizards before the snake arrives and six years later.
| Measurement | Before arrival | Six years after arrival |
|---|---|---|
| Adult female lizards | 600 | 230 |
| Eggs laid per adult female | 8 | 14 |
| Young reaching adulthood per 100 eggs | 25 | 6 |
Which conclusion about the future of the lizard species is best supported by the data?
Each female lays more eggs, but fewer of her young reach adulthood, so the species could become extinct.
Fewer adults now compete for food, so more young reach adulthood, and the species is likely to survive.
Each female lays more eggs, so more of her young reach adulthood, and the species is likely to survive.
The snake must be eating only adult lizards, so the species could become extinct as adult numbers fall.
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.