Accumulation of Variation During Reproduction

We all know that reproduction is the only process by which life exists on earth. So, it can also be termed as the process of creation of life. This is the only way by which there is continuity of life on earth and no one can deny from this truth. Reproduction is needed for every living organism to maintain their existence on earth as during this process one or more offspring are produced from parent organisms. 

Offspring produced during the reproduction process are not identical to each other.  But this variation varies from mode of reproduction. Their are mainly two modes of reproduction one is sexual reproduction: when two parents of opposite sex are involved and another on is asexual reproduction: in this single parent is able to reproduce itself. 

How Variation Occur in Offspring

Variations vary on the types of reproduction:

A. Variation in Asexual Reproduction:

In case of asexual reproduction single parent is involved in the process so the trasfer of genetic material is from single parent only. Due to this reason not much variation is seen in these types of offspring; only little changes can be seen because of inaccuracies happening during DNA copying mechanism. 

Example: Very minor variation can be seen in case of fruits and vegetables. 

B. Variation in Sexual Reproduction: 

In case of sexual reproduction two parents are involved as there is fusion of gametes from two different individuals. Due to which their genes get mixed up and causes maximum number of variations in their offspring and due to this offspring looks different from their parents.

This variation which is accumulated in an offspring is passed from generation to generation and this maintains genetic continuity of an organism. These variations are noticeable from generation to generation.

 Example: Human being offspring show accumulation of variation. 

Importance of Variations

As variation is a complex process by which we can determine similarities and dissimilarities present in an individual offspring. There are so many advantages of variations. Some of them are listed below:

• Evolution occurs because of variation in an individual. 

• Because of variations we can differentiate offsprings of single parents whether it is sexual or asexual mode of reproduction.

• Variations lead to the base of healthy genes from generation after generation.

• It is easy to adapt in any condition with the help of variations.

• It is helpful in the selection process of the best trait. 

Why Variation is Needed?

Each organism reproduces to increase their population so that they can maintain their existence on earth. As we know that the environment is not the same everywhere and to adapt in every adverse condition variation is needed. As environmental factors change with change in temperature, climate, humidity, resources, etc. 

To survive in these conditions it is must to adapt with those conditions. These adaptations can be done with the help of variations in an individual and all these variations come due to changes in DNA and body design. The meiosis process creates a DNA different from the parent cell due to crossing over and recombination process. A change in the information on DNA implies it is the initiation of variation. 

Steps Which Leads to Variation

• A cell is the structural and functional unit of living organisms. 

• Cells have nuclei inside which they carry genetic information for the upcoming generation in the form of DNA (DeoxyriboNucleic Acid). 

• So the main factor which is working behind reproduction is replication of DNA and this process starts with the help of original DNA and at last replicas get separated from original DNA strand. 

• From this process we get new DNA strand and by new DNA strand new protein code is also present on new DNA. 

• They look similar in nature but not identical to each other. 

During the process of gametogenesis the meiosis process occurs and due to this process offspring DNA is different from parental DNA due to crossing over and recombination process. Due to crossing over and recombination process there occur change in information present in DNA and due to this reason there occurs variation in an individual. Depending on these processes variation can be slow or drastic and this variation is needed for the process of evolution.