A fish farm has selectively bred salmon for rapid growth. The same strain is now used on several farms. During a disease outbreak, the numbers of salmon that survived were recorded.
| Salmon group | Number of salmon at start | Number surviving the disease |
|---|---|---|
| Selectively bred strain | 2000 | 180 |
| Salmon with greater genetic variation | 2000 | 1120 |
Explain why using the selectively bred strain could make the supply of salmon less reliable if this disease affects the farms.
127 exam-style questions on OCR GCSE Biology 6.2 Feeding the human race, covering 6.2.1 Biological factors affecting food security, 6.2.2 Agricultural solutions to growing demand, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, 6.2.5 Steps in genetic engineering, 6.2.6 Benefits and risks of gene technology in agriculture, and 6.2.7 Biotechnological solutions to growing demand. Each one has a worked solution and a mark scheme showing where the marks go.