Sexual and Asexual Reproduction
Master Sexual and Asexual Reproduction for GCSE Biology with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. Sexual reproduction needs two parents and gametes and creates variation, while asexual reproduction needs one parent and produces genetically identical clones.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Reproduction occurs in two forms, and the difference comes down to whether gametes and genetic variation are involved.
Sexual reproduction involves the fusion of male and female gametes — sperm and egg in animals, pollen and egg cells in flowering plants. Because there are two parents, there is a mixing of genetic information, so the offspring show variation.
Asexual reproduction involves only one parent and no gametes. There is no mixing of genetic information, so the offspring are genetically identical to the parent — they are clones. It involves mitosis rather than meiosis.
Revision notes
Sexual reproduction
Two parents contribute gametes, which fuse at fertilisation.
Gametes are produced by meiosis. The mixing of genetic information from two parents produces variation in the offspring, which is an advantage if the environment changes.
Asexual reproduction
One parent, no gametes, no fusion and no mixing of genetic information.
It involves mitosis, so the offspring are genetically identical clones. It is faster and requires only one parent, which allows rapid population growth in favourable conditions.
Advantages of each
Sexual: variation in offspring, so a species can adapt to environmental change by natural selection. Selective breeding is also possible.
Asexual: only one parent needed, more time and energy efficient, and faster, so many identical offspring can be produced when conditions are favourable.
Key points
- Sexual reproduction involves the fusion of gametes.
- It produces variation because two parents contribute genes.
- Gametes are formed by meiosis.
- Asexual reproduction involves one parent and no gametes.
- Asexual offspring are genetically identical clones.
- Asexual reproduction involves mitosis.
Worked examples
Example 1
State two differences between sexual and asexual reproduction. [2 marks]
Model answer
Sexual reproduction involves two parents and the fusion of gametes, whereas asexual reproduction involves only one parent and no gametes (1 mark). Sexual reproduction produces genetic variation in the offspring, whereas asexual reproduction produces genetically identical clones (1 mark).
Example 2
Give one advantage of sexual reproduction. [2 marks]
Model answer
It produces variation in the offspring (1 mark), so if the environment changes the species is more likely to survive by natural selection (1 mark).
Example 3
Give two advantages of asexual reproduction. [2 marks]
Model answer
Only one parent is needed, so it is possible to reproduce without finding a mate (1 mark). It is faster and more energy efficient, so many offspring can be produced quickly in favourable conditions (1 mark).
Common mistakes
Saying asexual reproduction produces some variation.
It produces genetically identical clones. Variation only arises from mutation.
Confusing mitosis and meiosis.
Asexual reproduction uses mitosis; gametes for sexual reproduction are made by meiosis.
Giving only one advantage when two are asked for.
Read the mark allocation carefully.
Saying sexual reproduction is always better.
Each has advantages depending on the environment.
Exam tips
- Learn the definitions around gametes and number of parents.
- Link variation to survival when the environment changes.
- Keep mitosis and meiosis attached to the right process.
- Give the number of advantages the marks require.
Key terms
- Gamete
- A sex cell containing half the usual number of chromosomes.
- Fertilisation
- The fusion of male and female gametes.
- Clone
- An organism genetically identical to its parent.
- Variation
- Differences between individuals of the same species.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.