The difference between asexual and sexual reproduction is mainly the fusion of gametes. In asexual reproduction, a new individual develops from one parent. Fertilization does not occur. The offspring are usually genetically similar to the parent, except when mutations take place. Binary fission, budding, fragmentation and vegetative propagation are some of the ways by which it occurs. In Hydra, a bud on the body can develop into a new individual.
Sexual reproduction occurs by the union of two gametes, forming a zygote. The gametes may come from two individuals or, in some species, from the same individual. During meiosis, the chromosome number is reduced and genetic material is rearranged. Fertilization brings the chromosome sets together again. Offspring usually differ genetically from the parents and from one another.
Asexual vs Sexual Reproduction – Comparison Table
| Basis | Asexual reproduction | Sexual reproduction |
|---|---|---|
| Process | A new individual is produced without the fusion of gametes. | Two gametes unite to begin the formation of a new individual. |
| Parent involvement | One parent is involved. | Gametes may come from two individuals. In some species, both are produced by the same individual. |
| Gametes | Fusion of gametes does not take place. | Gametes are formed and later unite. |
| Fertilization | Absent. An egg may also develop without fertilization in parthenogenesis. | The union of gametes is called fertilization. |
| Zygote | No zygote is formed through gamete fusion. | A zygote is formed after fertilization. |
| Meiosis | It is not required for common asexual methods such as budding and vegetative propagation. | Meiosis forms part of the sexual life cycle. It reduces the chromosome number. |
| Chromosome number | The chromosome number is generally maintained as the offspring develops from the parent. | Meiosis reduces the number of chromosome sets. Fertilization brings the sets together again. |
| Genetic material | There is no mixing of genetic material from two gametes. | Genetic material carried by the gametes is brought together. |
| Offspring | The offspring are usually genetically similar to the parent. Mutation may cause differences. | Different combinations of genes are produced, and the offspring generally differ from their parents. |
| Need for a mate | Another individual is not needed for reproduction. | Two gametes are needed. They do not always require two separate individuals. |
| Methods | Binary fission, budding, fragmentation and vegetative propagation are some methods. | Formation and fusion of gametes take place. The details vary among organisms. |
| Plant example | A potato tuber can give rise to a new plant. | In flowering plants, fertilization may take place in the ovule, followed by seed formation. Not every seed is formed by fertilization. |
| Animal example | A bud develops on Hydra and may separate from the parent. | In animals such as toads, an egg and sperm unite during fertilization. |
Difference Between Asexual and Sexual Reproduction
- Parent involvement- In asexual reproduction, the new individual arises from one parent. Sexual reproduction involves two gametes. They may be formed by two individuals or, in some species, by the same individual.
- Gametes- Fusion of gametes does not occur in asexual reproduction. In sexual reproduction, the gametes unite.
- Fertilization- It is absent in the asexual method. The union of gametes in sexual reproduction is called fertilization. A zygote is formed.
- Cell division- Binary fission is one of the ways by which an organism reproduces asexually. Meiosis takes place in a sexual life cycle and reduces the chromosome number. The chromosome sets come together again during fertilization.
- Offspring- Asexually formed offspring are generally similar to the parent in their genetic makeup. Mutation can cause a change. In sexual reproduction, the genetic material gets rearranged, and differences are seen among the offspring.
- Methods- Binary fission, budding, fragmentation and vegetative propagation are included under asexual reproduction. Formation and fusion of gametes occur in sexual reproduction.
- Examples- Hydra reproduces asexually by budding. A potato plant can arise from a tuber. In flowering plants, fertilization takes place within the ovule.
Similarities Between Asexual and Sexual Reproduction
- Formation of offspring- Both are methods by which new individuals are produced. The offspring develop from material provided by the parent organism.
- Inheritance- Genetic information is passed from parent to offspring in both methods. In asexual reproduction, it comes from one parent. In sexual reproduction, the gametes carry it to the offspring.
- Cell division- New cells are formed during the development of offspring in both. A bud, for example, grows by cell division. After sexual fertilization, the zygote also divides as it develops.
- Genetic change- Mutation may occur during either method. Sexual reproduction also rearranges genetic material when gametes are formed and united.
- Occurrence- Both methods are found among plants and animals. Some species can reproduce in either way. A plant may produce offspring from seeds as well as from its vegetative parts.
References
- Clark, M. A., Douglas, M., & Choi, J. (2018). Biology 2e. OpenStax. https://openstax.org/books/biology-2e/pages/1-introduction
- Fowler, S., Roush, R., & Wise, J. (2013). Concepts of biology. OpenStax. https://openstax.org/books/concepts-biology/pages/1-introduction
- Rye, C., Wise, R., Jurukovski, V., DeSaix, J., Choi, J., & Avissar, Y. (2016). Biology. OpenStax. https://openstax.org/books/biology/pages/1-introduction