A student states: 'Sexual reproduction in animals always produces offspring that show more variation than offspring produced by asexual reproduction.' Evaluate this statement.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Sexual reproduction involves the fusion of male and female gametes. Asexual reproduction involves a single parent and produces genetically identical offspring.
Model answer (5 marks)
1. Sexual reproduction involves fertilisation, the fusion of a male and a female gamete, which combines genetic material from two parents.
2. The gametes are haploid cells produced by meiosis, and meiosis introduces genetic variation through crossing‑over and independent assortment.
3. Asexual reproduction produces offspring that are genetically identical to the parent (clones), so there is no genetic variation.
4. Therefore, the statement is largely correct: sexual reproduction generally yields genetically varied offspring while asexual reproduction does not.
5. However, the statement is not absolute – environmental factors can create phenotypic variation in both types of reproduction, and some asexual processes (e.g. parasexual recombination) can introduce variation, so the claim has a limitation.
2. The gametes are haploid cells produced by meiosis, and meiosis introduces genetic variation through crossing‑over and independent assortment.
3. Asexual reproduction produces offspring that are genetically identical to the parent (clones), so there is no genetic variation.
4. Therefore, the statement is largely correct: sexual reproduction generally yields genetically varied offspring while asexual reproduction does not.
5. However, the statement is not absolute – environmental factors can create phenotypic variation in both types of reproduction, and some asexual processes (e.g. parasexual recombination) can introduce variation, so the claim has a limitation.
Examiner tips
- Use the exact terminology (fertilisation, meiosis, haploid, clones).
- Show the logical flow: fertilisation → meiosis → variation; asexual → no variation.
- Mention the limitation to demonstrate critical evaluation.
Common mistakes
- Confusing genetic variation with phenotypic variation.
- Failing to recognise that some asexual methods can introduce variation.
Mark scheme (5 marks)
- Agrees: sexual reproduction involves the fusion of gametes (fertilisation), combining genetic material from two parents
- Agrees: gametes are haploid cells produced by meiosis, and meiosis produces genetic variation in the gametes
- Agrees: asexual reproduction produces genetically identical offspring (clones) from a single parent, so there is no genetic variation
- Agrees or partially agrees: the statement is correct in that sexual reproduction produces genetically varied offspring whereas asexual reproduction does not
- Challenges: the statement is not always true / has a limitation, because environmental factors can cause variation in both sexually and asexually produced offspring, OR the statement only refers to genetic variation and ignores environmental variation
Key terms in this question
sexual reproduction · asexual reproduction · variation
Related
- All Pearson Edexcel A-Level Biology A (9BI0) revision notes →
- How to answer a "Evaluate" question →
- Decode the mark scheme abbreviations →
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