# A fish farmer wants to produce trout that grow faster and are more resistant to disease. Explain how the fish farmer could use selective breeding to achieve this over several generations.

> Pearson Edexcel A-Level Biology A (9BI0) — Topic 8 Use of Biological Resources · Explain · 5 marks

> Selective breeding (also called artificial selection) has been used for thousands of years to improve the characteristics of animals kept by humans. The fish farmer currently has a large population of trout with variation in growth rate and disease resistance.

## Mark scheme (5 marks)

1. Select/identify trout with the desired characteristics (fast growth AND/OR disease resistance) from the population
2. Breed the selected trout with each other (allow them to reproduce / cross the selected individuals)
3. Select offspring that show the desired characteristics (fast growth and/or disease resistance) from the next generation
4. Repeat the process over many generations
5. Over time, the desired characteristics become more common / the alleles for the desired traits increase in frequency in the population

## Key terms

- [selective breeding](https://www.gradenine.co.uk/glossary/selective-breeding)
- [generation](https://www.gradenine.co.uk/glossary/generation)

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-fish-farmer-wants-to-produce-3c9bff41) · Published by Druglandscape Ltd.