A research enclosure contains moth larvae and predatory beetles. The predatory beetles eat the moth larvae.
The table shows the estimated populations during seven weeks.
| Week | Number of moth larvae | Number of predatory beetles |
|---|---|---|
| 1 | 180 | 14 |
| 2 | 290 | 18 |
| 3 | 430 | 27 |
| 4 | 350 | 46 |
| 5 | 190 | 61 |
| 6 | 125 | 43 |
| 7 | 235 | 25 |
Explain the changes in the populations of moth larvae and predatory beetles from week 3 to week 7.
At the end of week 7, researchers add 200 moth larvae to the enclosure. They do not add any predatory beetles.
Predict which population is likely to reach its next peak first. Explain your answer.
83 exam-style questions on AQA GCSE Biology 7.2 Organisation of an ecosystem, covering 7.2.1 Levels of organisation, 7.2.2 How materials are cycled, 7.2.3 Decomposition, and 7.2.4 Impact of environmental change (HT only). Each one has a worked solution and a mark scheme showing where the marks go.