User talk:Neetish Dubey

CHARLES ROBERT DARWIN{1809-1882} Charles Darwin set out on a voyage when he was 22 years old. The five-year voyage took him to south America and the islands off its coast. The studies that he conducted during this voyage were to change forever the way we look at the variety of life on earth. Interestingly, after he got back to England, he never left its shores again. He stayed at home and conducted various experiments that led him to formulate his hypothesis that evolution took place due to natural selection. He did not know the mechanism whereby variations arose in the species. He would have been enlightened by Mendel's experiments, but these two gentlemen did not know of each other or their work! We often associate Darwin soloely with of theory of evolution. But he was an accomplished naturalist, and of the studies he conducted was to do with the role of earthworms in soil fertility.

ORIGIN OF LIFE ON EARTH Darwin's theory of evolution tells us how life evolved from simple to more complex forms and Mendel's experiments give us the mechanism for the inheritance of traits from one generation to the next. But neither tells us anything about how life began on earth in the first place. J.B.S. Haldane, a British scientist{who became a citizen india later},suggested in 1929 that life must have developed from the inorganic molecules which were present on earth soon after it was formed. He speculated that the conditions we see today, could have given rise to more complex organic molecules that were necessary for life. The first primitive organisms would arise from further chemical synthesis. How did these organic molecules arise? An answer was suggested by the experiment conducted by Stanley L. Miller and Harold C. Urey in 1953. They assembled an atmosphere similar to that thought to exist on early earth{this had molecules like ammonia,methane and hydrogen sulphide,but no oxygen} over water. This was maintained at a temperature just below 100°c and sparks were passed through the mixture of gases to simulate lightning. At the end of a week,15% of the carbon{from methane} had been converted to simple compounds of carbon including amino acids which make up protein molecules. So, can life arise afresh on earth even now?