What is Reproduction and why do we need it ?

What is Reproduction and why do we need it ?

Basic Definition

Reproduction is defined as the production of new organisms from the existing ones of the same species . Hence the word ‘Re’

Now,

• The process of reproduction requires a large amount of energy . 
• It is also not important to maintain the life of an individual like other life processes for eg. digestion, respiration etc. 

So why is there a need for an individual to invest its energy in a process that is not required to keep it alive?

Importance of Reproduction

• All the living organisms grow old and ultimately die . Therefore, new organisms need to be produced to replace the old ones.
• Hence, we can conclude that reproduction is essential for continuation of life on earth and for survival of species .
• Reproduction gives rise to more organisms with the same basic character as their parents. 

For example, a human gives rise to a human, a cat produces a cat and so on.

The Role of Genetic Material in Reproduction

• DNA is the genetic material of cells. This means that DNA stores all the information required for a cell to grow, perform various functions and respond to its environment.
• During cell division, this DNA is passed onto the daughter cells from the parent.
• Therefore, DNA is inherited from one generation to another. Because  of this reason, the offspring produced are similar to the parent.

• If we alter this information then the type of proteins formed will change thereby changing the whole body design.
• So, DNA replication (i.e. formation of a copy of the DNA) is a very important step in reproduction.

• This step ensures that the offspring receives the same copy of DNA as that of the parent.
• The process of DNA replication is accompanied by creation of additional cell apparatus and then the DNA copies separate.

How does DNA replication gives rise to variations:

• If the daughter cells produced are completely identical to the parent or not depends on how accurately the DNA copy is made .
• Since no biochemical reaction is completely reliable, some errors are expected to occur in the DNA copying which results in variation . 
• Because of these variations, the daughter cells are similar but not completely identical to the parent .
• If these variations are very drastic, the DNA may not be able to work and the cell dies.
• These discrepancies form the basis of evolution .