A marine biology student investigates the abundance of green algae (Enteromorpha) on the rocky floor of a sea cave.
She lays out a tape measure starting at the dark back wall of the cave, placing a quadrat at 2 m intervals towards the bright entrance. At each interval, she estimates the percentage cover of green algae inside the quadrat.
Her results are shown in the table below:
| Distance from the back wall of the cave (m) | Percentage cover of green algae (%) |
|---|---|
| 2 | 0 |
| 4 | 3 |
| 6 | 7 |
| 8 | 15 |
| 10 | 32 |
| 12 | 58 |
| 14 | 76 |
Describe the relationship between the distance from the back wall of the cave and the percentage cover of the green algae.
Explain, in detail, how the abiotic factor of light intensity affects the growth and distribution of the green algae as shown by these results.
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.