Two species of grasshopper, species K and species L, live in an upland grassland. Both species feed on the same grasses, and the amount of grass available is limited. An individual of species K eats grass more quickly than an individual of species L.
Scientists measured the percentage survival of each species after four weeks at different temperatures in a laboratory. They also recorded the mean number of each species at four grassland sites.
| Site | Mean daytime temperature in °C | Survival of species K in % | Survival of species L in % | Mean number of species K per 10 m² | Mean number of species L per 10 m² |
|---|---|---|---|---|---|
| P | 9 | 6 | 78 | 1 | 24 |
| Q | 13 | 24 | 83 | 6 | 18 |
| R | 17 | 86 | 88 | 27 | 6 |
| S | 21 | 92 | 90 | 33 | 4 |
The scientists then set up equal-sized mesh enclosures at sites R and S. The enclosures prevented grasshoppers from entering or leaving. Species K was removed from half of the enclosures. No grasshoppers were removed from the control enclosures.
The table shows the mean numbers of grasshoppers after one breeding season.
| Site | Species K where K was removed | Species L where K was removed | Species K in control enclosures | Species L in control enclosures |
|---|---|---|---|---|
| R | 0 | 20 | 28 | 7 |
| S | 0 | 23 | 35 | 5 |
Explain the distributions of species K and species L at sites P, Q, R and S.
Explain what the results from the enclosures show about competition between the two species. Suggest whether the mean mass of grass would be higher or lower in the enclosures where species K was removed than in the control enclosures.
82 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.