Researchers measured the carbon dioxide concentration in the air within a woodland canopy at the same location on a calm day.
| Time | Light conditions | Carbon dioxide concentration (ppm) |
|---|---|---|
| 05:00 | Before sunrise | 455 |
| 13:00 | Bright daylight | 405 |
| 23:00 | Four hours after sunset | 445 |
Explain the changes in carbon dioxide concentration between 05:00 and 13:00 and between 13:00 and 23:00.
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.