Ecologists investigated the population of woodlice (Oniscus asellus) in a woodland community over 16 weeks.
The table below shows the number of woodlice found under four different decaying logs:
| Log | 0 weeks | 4 weeks | 8 weeks | 12 weeks | 16 weeks |
|---|---|---|---|---|---|
| A | 24 | 20 | 15 | 9 | 4 |
| B | 28 | 23 | 18 | 11 | 5 |
| C | 32 | 27 | 22 | 14 | 7 |
| D | 26 | 22 | YYY | 12 | 4 |
| Totals | 110 | 92 | 71 | 46 | 20 |
Calculate the value of YYY which represents the number of woodlice under Log D at 8 weeks.
Calculate the percentage of the woodlice that were found under the logs at 12 weeks compared with 0 weeks. Give your answer to 1 decimal place.
63 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.