Explain why sexual reproduction leads to greater genetic variation in offspring compared with asexual reproduction.

Edexcel GCSE Biology (1BI0) — 3.1 Sexual and asexual reproduction · 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). Gametes are produced by meiosis, which creates genetically different cells. When gametes from two parents combine, the offspring inherit a new combination of alleles from each parent, increasing genetic variation. Asexual reproduction involves a single parent and produces genetically identical offspring, so no new combinations of alleles are formed.

Examiner tips

Use the term ‘fertilisation’ and ‘meiosis’ to show understanding of the process.
Explain that meiosis produces genetically distinct gametes and that combining two different gametes creates new allele combinations.
Mention that asexual reproduction gives identical clones, limiting variation.

Common mistakes

Confusing mitosis with meiosis for gamete formation.
Failing to state that asexual offspring are clones and lack new allele combinations.
Using vague terms like ‘different’ without explaining the genetic mechanism.

Mark scheme (4 marks)

Sexual reproduction involves the fusion of male and female gametes (fertilisation)
Gametes are produced by meiosis, which produces genetically different cells
Combining gametes from two parents means offspring inherit a different combination of alleles from each parent, increasing genetic variation
Asexual reproduction involves a single parent and produces genetically identical offspring (no new combinations of alleles)

Key terms in this question

sexual reproduction · asexual reproduction · genetic variation