Modes of Reproduction – Asexual & Sexual Reproduction

Animals use different modes to reproduce. Reproduction plays a major role in the process that involves the birth of an individual. Different organisms reproduce in different ways considering different factors that impact the process of reproduction. There are different modes of reproduction and this article aims to discuss these modes elaborately. There are two different modes of reproduction which are sexual and asexual. Follow this article to know more about these two modes of reproduction.

What is Reproduction?

Reproduction is the process in which an organism produces or give birth to a new offspring or individual of its own kind. It is a biological process and in order to understand the process, it is important for students to understand the reproductive organs to understand the process of reproduction.

What are the Modes of Reproduction?

The two modes of reproduction are:
1. Asexual reproduction
2. Sexual reproduction.

Asexual Reproduction

Asexual reproduction is a type of reproduction that involves the production of offspring by a single parent without involving the formation and fusion of gametes, fertilization, meiosis, transfer of genetic material between two individuals.
Asexual reproduction takes in both animals as well as plants.

Asexual Reproduction in Animals

Asexual reproduction takes place in various ways in different organisms. The various modes or types of asexual reproduction in animals is given below through a table.

Fig: Asexual Reproduction – Fission in Amoeba

Asexual Reproduction in Plants

Plants reproduce asexually in many ways, which are also seen in animals. The types and their examples are shown below through a table.

Fig: Fragmentation in Spirogyra

What is Vegetative Propagation?

The production of new plants from distinct vegetative parts of the plant body like stems, roots, leaves, bulbs, tubers, etc., is known as vegetative propagation.

It is of two types:
1. Natural methods of vegetative propagation.
2. Artificial methods of vegetative propagation.

Natural Methods of Vegetative Propagation

Plants propagate naturally through the underground stem, creeping stem, roots, leaves, aerial stem, etc. 

Some of the natural methods of vegetative propagation are given in the table below.

Fig: Vegetative Propagation by Rhizome – Ginger

Fig: Vegetative Propagation by Leaves – Bryophyllum

Artificial methods of Vegetative Propagation

It is the method developed by man for the horticultural and commercial production of crops. Many different plants are propagated at a very fast rate by this method.

The types and examples of the artificial methods of vegetative propagation are shown below through a table below:

Fig: Grafting

Sexual Reproduction

Sexual reproduction is a biparental mode of reproduction that involves the production of gametes and there is a fusion of male and female gametes to produce a diploid zygote.

Fig: Sexual Reproduction

Sexual Reproduction in Plants

1. The plants also reproduce sexually where fertilization of male and female gametes takes place, and finally, the zygote is formed. 
2. The flower is the reproductive structure in all flowering plants, and it is responsible for producing seeds upon fertilization that will grow into a new individual plant.
3. In flowering plants, double fertilization is seen and it is a complex fertilization mechanism. The process involves the fusion of a female gametophyte with two male gametes.
4. After fertilization is complete, no other male gamete can enter. The fertilized ovule forms the seed, whereas the tissues of the ovary become the fruit, usually enveloping the seed.

Fig: Double Fertilization in Flowering Plants

Sexual Reproduction in Animals

1. In animals, sexual reproduction takes place by the fertilization process between a haploid sperm and a haploid egg that results in the generation of a diploid zygote.
2. Examples of sexual reproduction are seen in higher organisms like humans and other mammals and plants.
3. Sexual reproduction is divided into two types, i.e., syngamy that takes place in multicellular organisms, and another one is a conjugation that takes place in single-celled or unicellular organisms.
4. The fertilization process may be internal in some animals such as reptiles, birds, humans, etc., or external fertilization in frogs, fishes, etc.

Fig: Image (a) – External Fertilization in Frog; Image (b) – Internal Fertilization in Hen

Advantages of Asexual Reproduction

Some of the advantages of asexual reproduction are as follows:
1. In asexual reproduction, a single parent is required.
2. The asexually reproduced organisms are less likely to become extinct as all organisms are capable or able to reproduce.
3. In this type, rapid population growth is observed only if there is a proper environmental condition.
4. This method requires very little energy to reproduce.
5. Each offspring is genetically similar to the parent.
6. Seedless plants can be produced by the vegetative propagation technique.
7. In asexual reproduction, the reproduction process is completed earlier and much faster when compared to sexual reproduction.
8. The plants raised by the vegetative propagation method bear fruits and flowers much earlier than those plants produced from seeds.

Advantages of Sexual Reproduction

The advantages of sexual reproduction are as follows:
1. Sexual reproduction is essential as it increases the genetic diversity in a population that supports natural selection.
2. The species can adapt to new environments due to variation, which gives them a survival advantage.
3. Sexual reproduction is the driving force for speciation, where new species are formed from the existing ones as new changes are introduced into the population via sexual reproduction.
4. In sexual reproduction, the disease is less likely to affect all the individuals in a population.

Disadvantages of Asexual Reproduction

Some of the disadvantages of asexual reproduction are as follows:
1. The organisms obtained from asexual reproduction does not lead to genetic variation in a population.
2. An organism that is born through the asexual reproduction method only has DNA from a single parent. 
3. The disease is likely to affect the whole population as there is no genetic variation in the organisms obtained from the asexual mode of reproduction.
4. Asexually reproduced organisms are not able to adapt themselves to change in the environment.

Disadvantages of Sexual Reproduction

The disadvantages of sexual reproduction are as follows:
1. Two parents are required to produce a new individual.
2. It takes time and energy to find a mate and reproduce.
3. Reproduction through sexual means is uncertain.
4. Favourable genetics might not be passed to the offspring.
5. Fewer offspring are typically produced.

Summary

Every living organism reproduces to continue its generation on the Earth. Through this article, we understood that different organisms have a specific type of reproductive method. Asexual reproduction involves only a single individual parent and involves types like budding, fission, fragmentation, sporulation, etc. Vegetative reproduction is the best way to propagate a greater number of plants. Sexual reproduction requires two parents, and a diploid zygote is formed by the fusion of two gametes. Though there are many disadvantages to asexual and sexual reproduction, both are necessary to run the generation and for the evolution of new species.

Frequently Asked Questions (FAQs) on Modes of Reproduction

Frequently asked questions related to modes of reproduction is listed as follows:

Q.1. What are the two main modes of reproduction?
Ans: The two main modes of reproduction are asexual reproduction and sexual reproduction.

Q.2. Why is reproduction so important?
Ans: Reproduction is important for the survival of all living things. Without a mechanism for reproduction, life would come to an end.

Q.3. Which mode of reproduction do humans belong to?
Ans: Human beings reproduce through the sexual reproduction method.

Q.4. What are 3 asexual reproduction examples?
Ans: The three asexual reproduction examples are budding, fragmentation and fission.

Q.5. Why is sexual reproduction important?
Ans: Sexual Reproduction produces variable offspring creating diversity and variation among populations. Therefore, sexual reproduction is important.

We hope this detailed article on the Modes of Reproduction helps you in your preparation. If you get stuck do let us know in the comments section below and we will get back to you at the earliest.