Diagrammatically represent the experimental set up that proved Oparin – Haldane hypothesis.

1. Oparin was a Russian chemist and John Haldane was a British scientist. The Oparin-Haldane hypothesis is one which was developed independently by the two scientists. Both independently said that the early Earth’s atmosphere was extremely reducing in nature.

2. In 1924, Oparin hypothesised that in the early developmental stages the atmosphere of Earth had negative charges which initiated reducing reactions. All the compounds formed had an excess of electrons. According to Oparin simple inorganic molecules led to the formation of complex organic compounds. In an aqueous environment, the simple organic molecules formed ‘coacervates’ which were colloidal aggregates. Oparin said that these coacervates took part in evolution. In 1929, Haldane came up with his theory. He too said that initially, Earth’s atmosphere was reducing. He said that the aqueous environment especially the oceans were like a huge cooking pot which received power from solar energy or lightning. As a result, varied organic compounds were formed.

3. Later in 1953, Harold Urey and Stanley Miller prepared a set up to perform Oparin-Haldane hypothesis. Miller prepared a flask which behaved as a closed system which contained gases like methane, ammonia, hydrogen and water. He passed sparks at 60,000 volts. After a week they noticed that ammonia and methane were mostly used up. The major products were carbon monoxide and nitrogen. The organic compounds formed were mainly amino acids (25 amino acids, main ones being glycine, alanine, aspartic acid), fatty acids, hydroxy acids and amide products.