Reproduction and meiosis — Edexcel GCSE Biology
Compare asexual and sexual reproduction, and explain how meiosis makes genetically different gametes.
Revision notes
3 short notes, in the order of the specification. Each one in short:
Asexual reproduction
Triple onlyAsexual reproduction needs only one parent and produces offspring that are genetically identical to the parent, so there is no variation in the population. Its advantages are that there is no need to find a mate and the reproductive cycle is rapid. Its disadvantage is that a new disease or a change in the environment could kill the whole population.
Sexual reproduction
Triple onlySexual reproduction involves two parents, each producing gametes that fuse at fertilisation. The offspring inherit a mixture of alleles from both parents, so they are genetically different and there is variation in the population. This means some individuals are likely to survive if the environment changes, but finding a mate takes time and energy.
Meiosis is the type of cell division that makes gametes. One parent cell divides to produce four daughter cells, each with half the number of chromosomes, which are genetically different from each other and from the parent cell. In humans, meiosis makes sperm and egg cells with 23 chromosomes, and fertilisation restores the full 46.
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Quick check questions
Give one advantage and one disadvantage of asexual reproduction.
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Advantage: no need to find a mate (or rapid reproductive cycle). Disadvantage: no variation in the population.
Give one advantage and one disadvantage of sexual reproduction.
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Advantage: variation in the population. Disadvantage: the requirement to find a mate.
How many daughter cells does one meiotic division produce?
Show answer
Four.
How many chromosomes are in a human gamete?
Show answer
23, which is half the number in a body cell (46).
Frequently asked questions
Why is meiosis important for sexual reproduction?
Meiosis is important because it makes gametes with half the number of chromosomes of a body cell. In humans, sperm and egg cells have 23 chromosomes, so when they fuse at fertilisation the zygote has the full 46. The gametes are also genetically different, which produces variation in the offspring.
What is the difference between mitosis and meiosis?
Mitosis produces genetically identical diploid body cells. Meiosis produces four genetically different haploid gametes, each with half the number of chromosomes of the parent cell. In humans, body cells made by mitosis have 46 chromosomes, while the sperm and egg cells made by meiosis have 23, so fertilisation restores 46.
What are the advantages of sexual reproduction?
Triple only The main advantage of sexual reproduction is variation in the population. Offspring inherit a mixture of alleles from two parents, so if the environment changes or a new disease appears, some individuals are likely to have characteristics that let them survive and reproduce. The disadvantage is that finding a mate takes time and energy.
What are the advantages of asexual reproduction?
Triple only Asexual reproduction has two main advantages: there is no need to find a mate, which saves time and energy, and the reproductive cycle is rapid, so the population can grow fast. The disadvantage is that the offspring are genetically identical, so a new disease or a change in the environment could kill them all.
Written and checked against the Edexcel GCSE Biology (1BI0) specification · Updated October 2026