Explain why the offspring produced by sexual reproduction show more genetic variation than those produced by asexual reproduction.

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

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

Model answer (4 marks)

Sexual reproduction involves the fusion of male and female gametes (fertilisation). Each gamete carries a different set of alleles, so the zygote receives genetic material from two parents. In contrast, asexual reproduction uses only one parent, producing offspring that are genetically identical to the parent. Consequently, sexual reproduction generates new combinations of alleles in the offspring, leading to greater genetic variation.

Examiner tips

  • Use the term 'fertilisation' for the fusion of gametes
  • Mention that each gamete contributes different alleles
  • Contrast with a single-parent asexual reproduction
  • Explain how new allele combinations increase variation

Common mistakes

  • Confusing asexual reproduction with mitotic cell division only
  • Failing to state that gametes come from two different parents
  • Using vague terms like 'different' without specifying alleles

Mark scheme (4 marks)

  1. Sexual reproduction involves the fusion of male and female gametes (fertilisation)
  2. Gametes from two different parents each contribute different alleles / genetic information
  3. Asexual reproduction involves only one parent, so offspring are genetically identical to the parent
  4. Sexual reproduction therefore produces different combinations of alleles in offspring, increasing variation

Key terms in this question

sexual reproduction · asexual reproduction

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