Scientists monitored organisms living beside a field. Aphids obtain food from stinging nettles, and ladybirds feed on the aphids.
At week 0, a new predatory insect arrived and began eating the aphids. The scientists recorded data from the same area at week 0 and week 6.
| Time | Total nettle leaf area in m² | Number of aphids | Number of ladybirds |
|---|---|---|---|
| Week 0 | 5.2 | 480 | 24 |
| Week 6 | 7.8 | 120 | 9 |
Calculate the percentage decrease in the number of aphids from week 0 to week 6.
Explain how the arrival of the new predatory insect could have caused the other changes shown in the table.
82 exam-style questions on AQA GCSE Biology 7.1 Adaptations, interdependence and competition, covering 7.1.1 Communities, 7.1.2 Abiotic factors, 7.1.3 Biotic factors, and 7.1.4 Adaptations. Each one has a worked solution and a mark scheme showing where the marks go.