A bird species feeds only on one seed-producing plant. A new herbivore arrives on its island. Bird numbers fall, but the herbivore does not eat birds or bird eggs.
Table
| Measurement | Before arrival | Five years after arrival |
|---|---|---|
| Adult seed-producing plants | 800 | 760 |
| Seeds produced per plant | 100 | 20 |
| Adult birds | 200 | 60 |
Which explanation best links the evidence to a possible future extinction?
Plant abundance changed little, but total seed production fell sharply, reducing bird survival and reproduction.
Plant abundance changed little, so seed availability remained similar, leaving direct predation as the supported cause.
Bird abundance fell sharply, so seed availability per bird increased, removing food shortage as a possible cause.
Bird abundance fell sharply, but surviving birds must acquire broader diets, preventing extinction through inherited adaptation.
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.