i. Stanley Miller and Urey designed an apparatus and created conditions similar to primitive atmosphere.
ii. The apparatus had a spark chamber with two tungsten electrodes, flask for boiling water, side tube connected to a vacuum pump condenser and U-shaped trap.
iii. The electric discharge was created by using electrodes in a spark chamber containing methane, ammonia, hydrogen and water vapours in the ratio 1:2:2 without air. This was done to create prebiotic environment.
iv. The flask containing water was heated to provide water vapour.
v. They passed the mixture through a condenser.
vi. They circulated the gases continuously in this way for one week and then analysed the chemical composition of the liquid inside the apparatus.
Observation: They observed a large number of simple organic compounds including some amino acids such as alanine, glycine and aspartic acid.
Conclusions:
All these complex organic compounds including amino acids, were synthesized non-enzymatically. This proved that complex organic compounds could be synthesized in reducing atmosphere without the help of enzymes and thus supported the Theory of chemical evolution.
