4.6.1.1 - Sexual and Asexual Reproduction
Reproduction produces new organisms. In this part of GCSE Biology, the important comparison is whether gametes fuse and whether genetic information is mixed. The detailed stages of meiosis come next, so this lesson uses only the brief prerequisite: meiosis makes non-identical cells, while mitosis makes identical cells.
Two routes to offspring
Living organisms can reproduce sexually or asexually. Both routes produce offspring, but they use different cells and give different genetic outcomes.
Gamete
A gamete is a sex cell used in sexual reproduction.
Sexual reproduction involves the fusion of a male gamete and a female gamete. Fusion means the gametes join. Because genetic information from two gametes is mixed, the offspring show variety.
Asexual reproduction involves one parent only. There is no fusion of gametes and no mixing of genetic information, so the offspring are genetically identical clones.
The cell division link is short but important:
| Cell division | GCSE link in this lesson |
|---|---|
| Meiosis | Leads to non-identical cells and is involved in forming gametes |
| Mitosis | Leads to identical cells and is the only cell division involved in asexual reproduction |
Do not turn this into a meiosis sequence yet. For this lesson, it is enough to know which type of cell division belongs with which reproduction route and why that affects genetic similarity.
Sexual reproduction
In animals, the male gamete is the sperm cell and the female gamete is the egg cell. Sexual reproduction involves these gametes joining.
In flowering plants, the male gamete is carried in pollen and the female gamete is the egg cell. The key AQA wording is pollen and egg cells in flowering plants.
Sexual Reproduction
Sexual reproduction is reproduction involving the fusion of male and female gametes.
The formation of gametes involves meiosis. This matters because meiosis leads to non-identical cells being formed. When male and female gametes fuse, genetic information is mixed. This mixing leads to variety in the offspring.
Variety means the offspring are genetically different rather than clones. You do not need to explain chromosome halving or the stages of meiosis in this lesson; that detail belongs in the meiosis lesson.
Asexual reproduction
Asexual reproduction is different because it involves only one parent. There is no fusion of gametes, so there is no joining of a male gamete and a female gamete.
Asexual Reproduction
Asexual reproduction is reproduction involving one parent and no fusion of gametes.
Because there is no gamete fusion, there is no mixing of genetic information. The offspring are genetically identical to the parent and to each other. Genetically identical offspring are called clones.
Clone
A clone is an organism or cell that is genetically identical to another organism or cell.
Only mitosis is involved in asexual reproduction. This fits the outcome: mitosis leads to identical cells being formed, so it can produce genetically identical offspring.
Comparison pattern
The cleanest way to compare the two types is to follow the same five checkpoints each time: parents, gametes, genetic information, cell division and offspring.
Continue this lesson.
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