Selective breeding has been used to produce cattle with increased milk yield. Describe how farmers could use selective breeding to develop a herd of cattle that consistently produces a high milk yield.

Eduqas GCSE Biology — 7.3 Variation and evolution · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

1. Identify and select cattle that give the highest milk yield as parents.
2. Breed the selected cattle together.
3. From the offspring, choose those with the highest milk yield and use them for the next breeding.
4. Repeat steps 2–3 over many generations until the herd consistently produces a high milk yield.

Examiner tips

  • Use the word "select" and "breed" to show the process. Show the cycle of selection and breeding. Mention that the process is repeated over many generations.
  • Include the key terms: "highest milk yield", "parents", "offspring", "herd".

Common mistakes

  • Writing a single breeding event instead of a repeated cycle. Using vague phrases like "good cows" instead of "highest milk yield". Omitting the step of selecting offspring for the next generation.

Mark scheme (4 marks)

  1. Identify and select cattle with the highest milk yield as parents
  2. Breed selected cattle together
  3. Select offspring with the highest milk yield and breed them again
  4. Repeat the process over many generations until the desired characteristic is established in the herd

Key terms in this question

selective breeding

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