A disease kills most of the heather plants on a moor but does not affect the other plant species there. Caterpillars of moth species R feed only on heather. Caterpillars of moth species S feed on heather, grasses and bilberry. The table shows the estimated numbers of caterpillars of each species on the moor before and after the disease.
| Moth species | Estimated number of caterpillars before the disease | Estimated number of caterpillars after the disease |
|---|---|---|
| R | 1200 | 150 |
| S | 900 | 760 |
Explain the difference between the effects of the disease on the two moth populations. Use data from the table in your answer.
82 exam-style questions on Edexcel GCSE Biology 9.1 Ecosystems and interdependence, covering 9.1.1 Levels of organisation in ecosystems, 9.1.2 Abiotic and biotic factors, 9.1.3 Importance of interdependence, 9.1.4 Parasitism and mutualism, and 9.1.5 Determining number of organisms in an area. Each one has a worked solution and a mark scheme showing where the marks go.