Selective breeding is used to improve characteristics in dogs. A breeder wants to produce a breed of dog that consistently retrieves objects from water, selecting for webbed feet and a water-resistant coat. Explain how the breeder would use selective breeding to produce a breed of dog with both of these desirable characteristics.

Pearson Edexcel International GCSE Biology (4BI1) — 5.2 Selective breeding · Explain · 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 parent dogs that display the desired traits – webbed feet and a water‑resistant coat.
2. Breed those selected parents to produce the first generation of puppies.
3. From the offspring, select those that show both webbed feet and a water‑resistant coat.
4. Breed the selected puppies together.
5. Repeat steps 3–4 over many generations until the traits are consistently present in the breed.

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 several generations.

Common mistakes

  • Confusing selection of parents with selection of offspring. Failing to state that the process is repeated over many generations. Using vague terms like "improve" instead of "select" and "breed".

Mark scheme (4 marks)

  1. Identify and select parent dogs that show the desirable characteristics (webbed feet and/or water-resistant coat)
  2. Breed the selected parents together to produce offspring
  3. Select offspring that show the desirable characteristics and breed from these
  4. Repeat the process over many generations until the desirable characteristics are consistently present in the breed

Key terms in this question

selective breeding · desirable characteristics

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