Experimental Evidence for Abiogenic Molecular Evolution of Life
Harold C. lirey (1893•1981), an Astronomer, accorded the first adequate recognition of Opartn-Haldane’s view on the origin of life In 1952. Urey asked his student Stanely L. Miller, a biochemist, to replicate the primordial atmosphere as propounded by Opartn and Haldane. Miller (1953) made the first successful simulation experiment to assess the validity of the claim for origin of organic molecules in the primeval Earth condition. Miller sealed in a spark chamber a mixture of water H20, methane (CH4), ammonia (NH3) and hydrogen gas (h2). He made arrangement for insertion of two electrodes to provide electrical energy (Simulation of lightening) to the spark chamber. The spark chamber was connected to another flask with arrangement for boiling water (provision for evaporation). The other end of the spark chamber was connected to a trap by a tube that passed through a condenser (an arrangement for condensation and collection of aqueous solution, equivalent to rain and Haldane’s soup). The trap, in turn, was connected with the flask for boiling water (arrangement for circulation). The control apparatus contained every arrangement except that It was devoid of energy source.
After eighteen days, significant amount of the simple major organic compounds (monomers), such as amino acids and peptide chains, began to appear in the aqueous sample of the experimental set. On the contrary, insignificant amount of organic molecules was formed in the control apparatus. Therefore, the obvious Inference was that abiotic synthesis of organic monomers occurred in the simulated experimental conclusion. By analogy, such synthesis could have occurred in the primitive atmospheric condition. Later on many scientists repeated Miller’s experiment using slightly different starting materials and UV radiation or other energy sources. All of them could successfully synthesize amino acid and related compounds. With hydrogen cyanide (HCN) even adenine and other nitrogen bases were produced.