Reproductive process is not essential for an individual. But it is very necessary for the continuity of the species. Reproduction performs following functions:
(i) In the process of reproduction one generation of living organisms produces the next generation i.e., parents produce offspring like themselves. Thus, this process preserves a species and maintains continuity of the race.
(ii) Reproduction is also the means of increasing the population of a species.
(iii) Reproduction plays an important role in evolution by transmitting favourable variation from parents to offspring.

An offspring is exactly similar to its parent in the case of asexual reproduction where a single parent gives rise to the offspring. For eg plants produced by vegetative propagation.
The off-spring produced by sexual reproduction is not similar to the parent as it is formed due to the fusion of male and female gametes which causes variations. 

Variations are important as they ensure the survival of species over time and with the changing conditions. The niches and the environmental conditions change with time, the variations in the species helps them to adjust, adapt and survive the changes.

The information for inheritance of features from parents to the next generation  is in the form of DNA molecules. DNA found in chromosomes in the nucleus of the cells has the information for making proteins which lead to body design of an organism. Different proteins lead to altered body designs. Thus to ensure similar body design the DNA needs to be copied in reproduction.