An ecology student investigates the distribution of a grass species growing in a meadow adjacent to a large, mature beech tree. The student lays out a tape measure starting from the base of the tree trunk and places a quadrat on the ground at regular intervals. At each distance, they record the percentage cover of the grass species within the quadrat. The table below shows their results:
| Distance from the tree trunk (m\text{m}m) | Percentage cover of grass (%\%%) |
|---|---|
| 1 | 8 |
| 2 | 12 |
| 3 | 25 |
| 4 | 48 |
| 5 | 72 |
| 6 | 90 |
Calculate the percentage increase in grass cover when moving from 2 m2 \text{ m}2 m to 5 m5 \text{ m}5 m away from the tree trunk.
Explain the biological mechanism that explains why the grass coverage is lower closer to the tree trunk.
67 exam-style questions on OCR GCSE Biology 4.1 Ecosystems, covering 4.1.1 Cycling of materials in ecosystems, 4.1.2 Microorganisms in cycling materials, 4.1.3 The carbon and water cycles, 4.1.4 Factors affecting decomposition, 4.1.5 Levels of organisation in an ecosystem, 4.1.6 Abiotic and biotic factors affecting communities, 4.1.7 Interdependence and competition, 4.1.8 Trophic levels, 4.1.9 Pyramids of biomass, and 4.1.10 Efficiency of biomass transfers. Each one has a worked solution and a mark scheme showing where the marks go.