MODES OF REPRODUCTION

Reproduction is a process by which one organism produces offsprings. It is one of the basic processes in all known life forms. Every organism we see around us is a direct result of reproduction.

Reproduction in animals and plants takes place in two ways:

• Sexually
• Asexually

Let us have a detailed look at the different modes of reproduction.

Modes Of Reproduction

Depending on the number of parents involved, there are different modes of reproduction. Every living organism reproduces by either of the two modes i.e. sexual reproduction or asexual reproduction.

The different modes of reproduction in animals and plants are explained below:

Sexual Reproduction

It is the mode of reproduction in which gemete cells from two organisms, one male and one female, combine to form a singular zygote. This zygote shares half of its genetic information with the father and the other half with the mother. Though the basics of it remain the same, there are many different modes of sexual reproduction in both plants and animals. The newly formed individual produced by sexual reproduction is different from parents, both genetically and physically.

Humans reproduce sexually by the fusion of sperm with egg (ovum) to produce a zygote called fertilization. Fertilization is the crucial stage of sexual reproduction. Without fertilization, sexual reproduction will not be complete.

Sexual Reproduction in Plants

Plants that reproduce sexually have sex parts which we know as flowers. The process of reproduction involves the fusion of male gametes, namely, pollen with the female gamete, also known as ovules. This fusion results in the formation of a zygote and an endosperm nucleus, which grow into seeds and fruits respectively.

Sexual Reproduction in Animals

Among the different modes of reproduction in animals, sexual reproduction is the most common one. Most animals reproduce sexually, though in a variety of different ways.

Sexual reproduction in animals involves the union of a haploid sperm and a haploid egg to form a diploid zygote, which shares its DNA with both the parent cells.

Certain invertebrates, such as tapeworms and certain other parasites,  reproduce through the process of self-fertilization in which they fertilize their egg with their own sperm.

Sexual reproduction in animals may happen through internal fertilization (humans, dogs) or external fertilization(certain reptiles and birds).

Asexual Reproduction

It is the mode of reproduction which involves only one organism. The offspring that is produced is genetically identical to the mother and almost always has the same number of chromosomes. Hence, they are called clones. Moreover, they are exact copies of their parent cell.

Organisms choose to reproduce asexually by different means. Some of the asexual methods are binary fission (e.g. Amoeba, bacteria), budding (e.g. Hydra), fragmentation (e.g. Planaria), spore formation (e.g. ferns) and vegetative propagation (e.g. Onion).

Asexual Reproduction in Plants

Some plants have the ability to reproduce asexually, that is, without the help of flowers or pollens. There are different modes of asexual reproduction in plants, both natural and human-induced.

In the natural mode of asexual reproduction, a plant can give rise to an offspring with the help of roots. Certain plants also use budding and cutting to reproduce asexually.

Human-induced asexual reproduction in plants includes grafting, layering, cutting and micropropagation.

Asexual Reproduction in Animals

Some simple animals, many of which are single-celled, reproduce asexually.

The different modes of asexual reproduction in animals include gemmules (sponges), fragmentation (planarians), regeneration (echinoderms) and parthenogenesis (ants, wasps)

Living things are wonderful. Wars, poverty, natural disasters, murders, hunting, etc., happen and exist in the world. But it is still estimated that our earth is the home to around 8 million species. One dies, another comes. It never ends and is a cycle of life. The secret is within us,it is reproduction in organisms. It helps organisms to continue their species. It is a life process like nutrition, movement, circulation, etc. Different modes of reproduction are discussed below.