Explain what is meant by selective breeding and describe one advantage and one disadvantage of using selective breeding in animals.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Selective breeding is the deliberate choice of organisms that possess desirable traits, such as higher milk yield or disease resistance, to mate together. This process is repeated over many generations until the trait becomes fixed in the population.
An advantage of selective breeding is that it produces animals with useful characteristics, for example, cattle that give more milk or chickens that grow faster.
A disadvantage is that it reduces genetic variation, making the population more vulnerable to disease or environmental changes.
An advantage of selective breeding is that it produces animals with useful characteristics, for example, cattle that give more milk or chickens that grow faster.
A disadvantage is that it reduces genetic variation, making the population more vulnerable to disease or environmental changes.
Examiner tips
- Use the definition of selective breeding first, then give one clear advantage and one clear disadvantage.
- Show the process of repeated breeding over generations.
- Use specific examples (milk yield, disease resistance).
Common mistakes
- Confusing selective breeding with random breeding or mutation.
- Failing to mention the reduction in genetic diversity as a disadvantage.
Mark scheme (4 marks)
- Selective breeding involves choosing organisms with desirable/wanted characteristics to breed together
- This is repeated over many generations until the desired trait is established/fixed in the population
- One advantage: produces animals with a useful/desired characteristic, e.g. greater meat/milk yield, disease resistance, or other valid benefit
- One disadvantage: reduces genetic variation/gene pool, which makes the population more vulnerable to new diseases or environmental changes
Key terms in this question
Related
- All Eduqas GCSE Biology revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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