The key difference between sexual and asexual reproduction is that sexual reproduction involves two parents of the opposite sex while asexual reproduction involves a single parent.
The ability to reproduce and produce a new generation of the same species is one of the fundamental characteristics of a living organism. It involves the transmission of the genetic material from the parental generation to the offspring generation, ensuring the characteristics of the species and perpetuating the characteristics of parental organisms. Before a new individual reaches its own reproductive stage, it normally has to go through a period of growth and development. Some members of the species will die before they reach reproductive age due to predation, disease and accidental death. So the remaining species will only able to produce more offspring and contribute to the continuation of the species. There are two basic types of reproduction; namely, asexual and sexual reproduction.
CONTENTS
1. Overview and Key Difference
2. What is Sexual Reproduction
3. What is Asexual Reproduction
4. Similarities Between Sexual and Asexual Reproduction
5. Side by Side Comparison – Sexual vs Asexual Reproduction in Tabular Form
6. Summary
What is Sexual Reproduction?
Sexual reproduction is a type of reproduction that involves two types of parents and the combining of genetic material of each parent. Parents produce gametes, and gametes fuse with each other during the sexual reproduction. As a result of syngamy, a diploid cell called zygote forms at the end of the sexual reproduction. Based on the types of gametes fusing with each other, there are two types of sexual reproduction; namely, isogamy and heterogamy. Isogamy is the union of structurally similar physiologically different gametes. It is found only in lower forms such as Protozoa. Heterogamy is the fusion of two clearly different kinds of gametes, distinguished as ovum and sperm.
Figure 01: Sexual Reproduction
Fertilization is the main event of sexual reproduction. However, there are some events occur before and after fertilization. Pre-fertilization events include gametogenesis and gamete transfer while post-fertilization events include the formation of zygote and embryo.
When compare sexual and asexual reproduction, sexual reproduction creates genetic diversity among the offspring. Genetic diversity is important since it provides material for natural selection. Also, genetic diversity is a key to evolution. As a result of recombination of DNA during the gamete formation by meiosis, genetically different gametes are produced. These gametes create the genetic diversity among the offspring.
What is Asexual Reproduction?
Asexual reproduction is one of the two main modes of reproduction. It involves only one parent. Hence, the offsprings are genetically identical with the parent. Prokaryotes such as bacteria and unicellular eukaryotic organisms such as Amoeba and Paramoecium reproduce asexually by cell division or binary fission of the parent cell.
Figure 02: Binary Fission
Hence, asexual reproduction is a type of reproduction done by a single organism without production of gametes. It usually results in the production of identical offspring, the only genetic variation arising as a result of random mutation among the individuals. There are three common modes of asexual reproduction: fission, budding and fragmentation in animals. Lower animal phyla such as prokaryotes, eukaryotes, cnidarians and Platyhelminthes use this type of reproduction.
What are the Similarities Between Sexual and Asexual Reproduction?
- Both sexual and asexual reproductions are modes for the propagation of the current generation into the future.
- Also, both sexual and asexual reproduction results in a new organism.
- Living organisms adopt these methods.
What is the Difference Between Sexual and Asexual Reproduction?
Sexual and asexual reproduction are two main types of reproduction shown by living organisms. The key difference between sexual and asexual reproduction is that sexual reproduction occurs between two parents while asexual reproduction occurs via a single parent. Asexual reproduction requires only a single divisible cell to produce a new organism, whereas sexual reproduction requires two gametes, their formation and fusion. Hence, this is also a difference between sexual and asexual reproduction. Moreover, a further difference between sexual and asexual reproduction is that sexual reproduction requires the formation of sexual organs, but asexual reproduction generally occurs without them.
Besides, gamete production takes place through meiosis in sexual reproduction. During the meiosis, genetic recombination is a common process. Hence, gametes show genetic variation, and it leads to the genetic diversity between offspring in sexual reproduction. However, asexual reproduction does not involve meiosis or genetic recombination. Therefore genetic variation is very low in asexual reproduction. Therefore, this is also a significant difference between sexual and asexual reproduction.
Below is an infographic showing the difference between sexual and asexual reproduction.
Summary – Sexual vs Asexual Reproduction
Sexual reproduction is a method of reproduction in which combination of genetic material of two individuals takes place in order to produce offspring. On the other hand, asexual reproduction is the second mode of reproduction in which no genetic recombination occurs, or no fertilization occurs. Hence, two parents involve in sexual reproduction while only single parent involves in asexual reproduction. Sexual reproduction results in genetically different offspring while asexual reproduction produces genetically identical offspring. Thus, this summarizes the difference between sexual and asexual reproduction.
Reference:
1. Nature News, Nature Publishing Group. Available here
2. “Asexual Reproduction.” Wikipedia, Wikimedia Foundation, 31 Dec. 2018. Available here
Image Courtesy:
1.”The sperm and ovum during fertilization”By Atdoan0 – Own work, (CC BY-SA 4.0) via Commons Wikimedia
2.”Binary Fission 2″By Ecoddington14 (CC BY-SA 3.0) via Commons Wikimedia