variations

Yesterday when I met Mr.Anilkumar S.G who is a specialist in plant breeding we had serious discussion about variations. He remarked that variation is the beauty of nature and the principle of nature. I supported him. We can see people taking part in a march past are alike but closely observing different. Variation is a must. Without which evolution is not possible. How it is happening in organisms? It is by mutation, the changes affecting in the Genes, the genetic material in an organism.