Reproduction – Definition, Types, Characteristics, Examples

Reproduction is the process of giving birth to an offspring. Reproduction is essential for the continuation of a species. Reproduction word means to make a copy of themselves. It is a biological process in which an organism reproduces offspring sexually or asexually. Through reproduction, individuals of different species are still present on this planet.

Living organisms show two types of reproduction:

• Sexual reproduction
• Asexual reproduction

Asexual Reproduction

Asexual reproduction is the type of reproduction in which only a single parent is involved, with no possibility of mixing two or more two different genetic materials i.e. DNA
Example: Budding in Hydra, Fission in Amoeba

Types of Asexual Reproduction

Binary Fission

In Fission, a parent splits into two or more individuals of almost equal size who are identical to the mother cell. For Example bacteria, archaea, and unicellular eukaryotes like protists, and some fungi use this kind of reproduction.  

Budding

In budding, a bud-like outgrowth develops on the parent body, which is similar to the parent organism. Organisms reproduce by splitting off new individuals from existing ones through budding and resulting in genetically identical parent and daughter organisms. The bud may remain linked, or it may break loose through the parent. Budding generally occurs in eukaryotic species such as single-celled yeast and multicellular Hydra.

Fragmentation

In Fragmentation, the body is divided into many fragments, which eventually evolve into whole creatures. This method is frequently seen in worms, fungi, and plants, in addition to starfish. 

Vegetative Propagation

In plants, Asexual reproduction occurs through their vegetative parts such as leaves, roots, stems, and buds. This process is known as vegetative propagation. For example runners/stolon, potato tubers, onion bulbs, etc., all reproduce through vegetative propagation 

Spore Formation

Spore formation helps organisms in asexual reproduction. During unfavorable conditions, the organism develops sac-like structures called sporangium which contain spores. In favorable conditions, the sporangium burst opens and spores are released that germinate to give rise to the new organisms. For example, different species of fungus-like Bread Mold.

Sexual Reproduction

Sexual reproduction is the type of reproduction, which involves two parents giving rise to an offspring. In this type of reproduction, the offspring inherits half of the genetic material from the father and another half from the mother gamete, i.e. The DNA of the offspring will have an equal share of the genetic material of the mother and father. Example: humans, Fish, Frog, etc.

There are different organs present in an organism for the process of fertilization.  These special organs produce the male and female gametes, respectively. Which fuse to form the offspring.  The mating male and female gamete is called sexual reproduction. 

Male Reproductive Organ

It consists of a pair of testes, penis, sperm, sperm ducts. After achieving the adolescence age in which the secondary character developed. Secondary character, involved development of a beard, and secretion of hormones i.e. testosterone which is required for the proper development of male gametes i.e. sperms. Sperms are formed by the process known as Meiosis. It is the process in which cells are divide in which chromosome no reduce to the half also known as reductional Division. Once the sperm are formed, they are stored in epididymis, and this process is known as Spermatogenesis.

Female Reproductive Organ

The female reproductive system contains a pair of ovaries, a pair of fallopian tube, uterus. Egg or ova is the female gamete. After achieving adolescence age the secondary developments of female body starts which include breast enlargement, release of hormones Estrogen which helps the ova to mature the egg. The mature egg is released from the ovary into the fallopian tube. In one month, only one egg is released, this cycle is known as Menstrual Cycle. Ovum is the largest cell of human body, the female also formed from meiosis and the process is known as Oogenesis.

Fertilization

Fertilization is the process in which male and female gametes fuse and form a diploid 2n cell known as Zygote. 

Both male and female gametes (cell) are haploid in condition n. The sperm fuse with the egg in the fallopian tube and after fusing the zygote move from the fallopian tube to the inner epidermis layer of the uterus and there the process known as gastrulation start. Inner epidermis is the layer which implant the embryo and help in developing the embryo into  fetus and after 9 months fully, mature baby is developed. The childbirth process is known as Parturition.

Difference between Sexual and Asexual Reproduction

	Asexual Reproduction	Sexual Reproduction
1.	Occurs in prokaryotic microorganisms and  in some eukaryotic organisms.	Occurs in multicellular organisms.
2.	It involves single parents i.e. Mother cell	It involves both male and female cells.
3.	No formation of gametes.	Formation of gametes.
4.	Somatic cells of parents are involved.	Germ cells of parents are involved.
5.	No fertilization occurs.	Fertilization is observed.
6.	No involvement of reproductive organs.	Presence of fully developed reproductive organs.

Conceptual Questions

Question 1: Define the term reproduction? How many types of reproduction are present?

Answer:

Reproduction is the process of giving birth to an offspring. Reproduction is essential for the continuation of a species. Reproduction word means to make a copy of themselves. Reproduction is a biological process in which an organism reproduces offspring sexually or asexually. Through reproduction, individuals of different species are still present on this planet.
There are 2 types of reproduction:

1. Asexual Reproduction.
2. Sexual Reproduction.

Question 2: What do you understand by asexual reproduction? Give an example of an organism showing this type of reproduction.

Answer:

Asexual reproduction is the type of reproduction in which only a single parent is involved, with no possibility of mixing two or more two different genetic materials i.e. DNA
Example: Budding in Hydra, Fission in Amoeba.

Question 3: What do you understand about sexual reproduction?

Answer: 

Sexual reproduction is the type of reproduction, which involves two parents giving rise to an offspring. In this type of reproduction, the offspring inherits half of the genetic material from the father and another half from the mother gamete, i.e. The DNA of the offspring will have an equal share of the genetic material of the mother and father.

Question 4: Why is sexual reproduction is preferred over asexual reproduction in terms of the evolution of life?

Answer:

As sexual reproduction involves two parents i.e. 2 different sets of genes coming together to form new offspring, it helps in expanding the gene pool of that species which helps that species to adapt to a new environment/surrounding better and faster. While in asexual reproduction the offspring have the same genetic makeup as their parent because there is no mixing of two parents’ DNA, hence the offspring are clones of their mother cell.