Asexual Reproduction

All the living organisms grow old with time and ultimately die. In fact, every living organism remains alive on this earth for a limited period of time and then dies. So, new organisms have to be produced in place of those who die. The production of new organisms from the existing organisms of the same species is known as reproduction. In most simple words we can say that reproduction is the creation of new living things (from the existing living things). Actually, one of the most important characteristics of living organisms is their ability to reproduce more members of their species. Reproduction is essential for the survival of a species on this earth. So, living organisms produce more organisms of their kind to maintain the life of their species on this earth.

The process of reproduction ensures continuity of life on earth. For example, human beings reproduce by giving birth to babies (sons and daughters). These babies grow and ultimately become adults. So, when the old parents die, their sons and daughters keep living on this earth. These sons and daughters also reproduce by giving birth to more babies, and this process goes on and on. Thus, reproduction by human beings ensures that the human species will continue to exist on this for all the time to come. Similarly, cats reproductive by giving birth to kittens so that their species may live for ever. And dogs reproduce by giving birth to puppies so that their species may continue to live on this earth.

Reproduction may be defined as the process by which living things produce offspring (i.e. young ones) of their own kind. They reproduce by various means - for example, human beings and other mammals reproduce by giving birth to the babies, most birds reproduce by laying eggs and most plants reproduce through seeds.

All the different ways of reproduction can be divided into two main groups : asexual reproduction and sexual reproduction. Thus, there are two main methods of reproduction in living organisms :

(i) asexual reproduction, and               (ii) sexual reproduction

This means that new living organisms (or animals) can be made either by the method of 'asexual reproduction' or by the method of 'sexual reproduction'. In order to understand this please keep in mind that certain organisms contain 'reproductive cells' (called 'sex cells' or 'gametes') in their bodies whereas some other organisms do not contain 'reproductive cells' ('sex cells' or 'gametes') in their bodies.

Asexual Reproduction

The production of a new organism from a single parent without the involvement of sex cells (or gametes) is called asexual reproduction. It is called  asexual reproduction because it does not use special cells called 'sex cells' (or gametes) for producing a new organism. In asexual reproduction, a part of the parent organism  separates off and grows into a new organism. Thus, in asexual reproduction, only parent is needed to produce a new organism. But no sex cells are involved in asexual  reproduction. The offspring produced by this process are identical to their parents. Some of the examples of asexual reproduction are : binary fission in Amoeba; and budding in Hydra. Other different type of asexual reproduction are fragmentation, spore formation and vegetative propagation.

In case of plants another type of asexual reproduction known as vegetative reproduction or vegetative propagation . In this process offsprings are produced from the fragments of the parent plants. Different type of vegetative propagation occur based on the part used. Some of them are

Asexual reproduction is the simplest method of reproduction. It takes place mainly in those animals whose bodies have a simple structure. In asexual reproduction, the young one (or offspring) produced is an exact copy of the parent.

Sexual Reproduction

The production of a new organism from two parents by making use of their sex cells (or gametes) is called sexual reproduction. In sexual reproduction, the sex cell of one parent fuses with the sex cell of the other parent to form a new cell called 'zygote'. This zygote then grows and develops to form a new organism. Thus, in sexual reproduction, two parents are needed to produce a new organism.

                                          (a)                                                                                                       (b)

In the image (a) binary fission of Ameoba is shown where single parent body divides into two daughter cells. In the image (b) different type of vegetative propagation are shown based on the part used.  

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