Living beings have many processes in common.
Among all the common processes there is one very interesting and wonderful process which is called as reproduction.
It means all the living beings reproduce. What is reproduction?
It is a complex physiological process through which new living beings are reproduced. This process increases the number of individuals in a species.
Reproduction is not necessary for the maintenance of life of an individual organism. So it is not called as a Life Process.
Nutrition, Respiration, Excretion, and Transport etc. processes maintain life.
Reproduction is not necessary for the survival of an organism. So, this is not called as a life process.
In natural state the process of reproduction may be – Sexual and Asexual.
Sexual reproduction is possible between male and female organisms of the same species.
After all the similarities among individuals of the same species organisms differ from each other in many ways. This is called as Variation.
Reproduction and Variation
The body of every organism has specific shape and design. It is due to the codes that remain embedded in the molecules of DNA found in the nucleus of a particular organism.
Each DNA molecule has a tendency of producing its copy during reproduction so as to retain the number of DNA molecules equal in all the cells.
DNA has information regarding synthesis of a particular protein. Different types of proteins are synthesized if information contained in the DNA molecules is changed. This contributes to the change of body shape or design. Thus, fundamental step of reproduction is preparation of copy of DNA.
Inside cells, different chemical processes are involved to produce copies of DNA. These copies are not always exactly similar and some changes are bound to occur. These changes cause changes in organisms.
Thus it is clear that variations in organisms are produced spontaneously and these variations are basics of evolution.
Here, it is also clear that during reproduction living organisms don’t become able to reproduce their exact copies of individuals.
Variations may be beneficial to a species but not necessarily to an individual.
How? It is due to variations that different types of individuals are produced. It keeps up the existence of a species. So, these are essential for a species but not for an individual.
Importance of variations
Variations help an organism in changing conditions of organism.
Every organism lives in specific area which is called as its niche.
Every organism is adapted to its niche. However, if conditions of niche change its organisms get into trouble. At this stage only those organisms survive who have maximum number of variations.
When conditions of environment change, a large number of organisms perish.
Variations alone keep some organisms alive.
Thus, a species remains alive during adverse conditions due to variations or adaptations of its individuals.