Oparin-Haldane theory of chemical evolution states that life originated from pre-existing, non-living organic molecules.
In 1953, S.L. Miller observed formation of amino acids from CH4,H7,NH3 and water vapour at 800o C. It states that life originated from pre-existing non-living organic molecules (e.g., RNA, protein, etc.). When the meteorites were analysed, it was observed that presence of similar compounds was confirmed which conclude that similar process is going on elsewhere in the space.
