Reproduction is one of the characteristics of an organism. Organisms give rise to other organisms of the same kind in life time and then continues its generation. The process of reproduction may be of various types. Diversified reproductive processes are being observed. I shall try to discuss all reproduction of Human and flower reproduction here.
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- 1 What is Reproduction?
What is Reproduction?
Reproduction is a biology process by which new organisms are generated. So it means that Reproduction is the process of producing babies or young animals and plants. It is the mechanism of species continuation.
The known methods of reproduction are broadly grouped into two main types:
1. Asexual Reproduction Process
2. Sexual Reproduction Process
1. Asexual Reproduction Process
In this system, an individual can reproduce without involvement with another individual of that species. The division of a bacterial cell into two daughter cells is an example of asexual reproduction. Asexual reproduction is not, however, limited to single-celled organisms. Asexual reproduction needs only one parent, unlike sexual reproduction, which needs two parents.
Since there is only one parent, there is no fusion of gametes and no mixing of genetic information. As a result, the offspring are genetically identical to the parent and to each other. They are clones. Asexual reproduction happens in lower animals. Asexual reproduction occurs in different ways.
Such as – budding, binary fission, fragmentation etc.
2. Sexual Reproduction Process
The process through which two animals of opposite sex (male and female) compete for their reproduction by means of producing male and female gametes, fertilizes and produce offspring is called reproduction. The process of sexual reproduction involves two parents. Both parents normally contribute one gamete or sex cell to the process. This process assures that the genetic information given to the offspring will be obtained equally from each parent. The female gamete is called the egg or the ovum and the male gamete is called a sperm. These gametes are formed in specialised reproductive structures called gonads.
Fertilization is necessary for sexual reproduction. It is a universal biological process. Sexual reproduction takes place by producing dissimilar gamete that is male. Fertilization occurs by the fusion of that is called fertilization. During sexual reproduction active sperm penetrates into the ovum and the two nucleus fuse together. The is cell is formed by the fusion of nucleus is zygote. It requires sometime for fertilization. Each of the sperm and ovum contains haploid number of chromosome it signifies it carries (one set of chromosome). Due to fertilization zygote is produced, Zygote is a diploid new cell that means it carries two set chromosomes. Maturity of sperm and ovum is the precondition of fertilization. Fertilization is a particular process. It happens only with the matured / full grown sperm and ovum of some species. Generally fertilization is unchangeable. Once an ovum is fertilised it will not fertilize again. On the basis of the place of occurrence, fertilization is divided into two types.
Each of the sperm and ovum contains haploid number of chromosome it signifies it carries (one set of chromosome). Due to fertilization zygote is produced, Zygote is a diploid new cell that means it carries two set chromosomes. Maturity of sperm and ovum is the precondition of fertilization. Fertilization is a particular process. It happens only with the matured / full grown sperm and ovum of some species. Generally fertilization is unchangeable. Once an ovum is fertilised it will not fertilize again. On the basis of the place of occurrence, fertilization is divided into two types.
1. External reproduction
2. Internal reproduction.
1 External reproduction:
If the fertilization takes place outside the body of male and female animals, generally in water is known as external reproduction, example in fishes. But exception are there, such as sharks and different fishes.
2. Internal reproduction :
The fertilization which takes place inside the reproductive organ of the female is called internal reproduction. This fertilization occurs introducing sperms of the male into the female reproductive organ. It is one of the characteristics in most of the terrestrial animals.
Some basic significance of fertilization:
Restoration of diploid chromosomes within the embryo accumulates heriditory characters of both male and female, makes the ovum active for its development. Chromsomes carry the characteristics of both father and mother. These characteristics combine, determine the sex of the embryo. Block picture shows the stapes of gamete formation is give below. For the continuity and restoration of hereditary, reproduction is essential. This process includes formation of embryo and gives birth to offspring. Man is unisexual, so that male and female reproductive organs are present in different individuals.
Concept of reproduction in organisms and its significance
Death is inevitable for life if it is born. If only death would have been occurred, once organisms would be extinct. But actually, is not happening because in one hand organisms are dying on the other hand organisms are also reproducing. Reproduction is such a physiological activity through which organisms continue the existence of their offspring by producing their replicas. The process through which organisms produce their offspring is called reproduction.
Reproduction is of two types, such as, asexual and sexual. Generally, in lower organisms, sexual reproduction does not occur but some lower organisms reproduce sexually. Most of the higher plants and all higher animals produce their offspring through sexual reproduction.
In sexual reproduction, two reproductive cells of opposite characters are fused. In this case, one is called male
reproductive cell and the other is called female reproductive cell or egg. Two types of reproductive cells can be produced in the same flower or in the same body. In higher plants, there are two types of reproductive cells produced in the same bodies. They are monoecious plants. When two types of reproductive cells are produced in separate bodies, these plants are called dioecious plants. The precondition of developing of any reproductive cell is that germinal mother cell will have to divide through meiosis.
As a result, the number of chromosomes in a reproductive cell becomes half than that of the mother cell. Later, zygote being divided repeatedly through the process stages of mitosis five stages of mitosis and its significance develops the new body of the newly born organism. In this way, an organism gives birth of many organisms. An organism this way also maintains the flow of its future generations.
If reproduction would not occur in organisms, they would be extinct. From a virus or bacterium up to human beings, all organisms maintain the existence of their species by reproducing their new generations. Which way an organism will accomplish its reproduction depends on the characteristics of the organisms. This is why when a lower organism does its reproduction through cell division then an organism of higher level accomplishes its reproduction through the complex process of sexual reproduction.