Explain why meiosis is important for producing genetic variation in a species.

Edexcel GCSE Biology (1BI0) — 3.2 Meiosis · 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. Meiosis produces four genetically different daughter cells (gametes). 2. Each gamete is haploid, containing half the chromosome number of the parent. 3. At fertilisation, the nuclei of the male and female gametes fuse, restoring the diploid chromosome number. 4. Because each gamete is genetically different, the offspring produced by fertilisation show genetic variation.

Examiner tips

Use the exact terms: ‘genetically different’, ‘haploid’, ‘diploid’, ‘fertilisation’. 2. Show the sequence: meiosis → haploid gametes → fertilisation → diploid offspring. 3. Keep the answer concise, matching the four points. 4. Avoid unnecessary explanation or repetition.

Common mistakes

Confusing meiosis with mitosis; not mentioning haploidy. 2. Mixing up the order of events (fertilisation before meiosis). 3. Writing that meiosis itself creates variation, rather than the combination of different gametes at fertilisation.

Mark scheme (4 marks)

Meiosis produces four genetically different daughter cells / gametes
The gametes produced are haploid (contain half the number of chromosomes)
At fertilisation, the nuclei of male and female gametes fuse, restoring the full (diploid) chromosome number
Because each gamete is genetically different, the offspring produced by fertilisation show genetic variation

Key terms in this question

meiosis · genetic variation