Explain the theory of chemical evolution.

Explanation

(i) According to the theory of chemical evolution primitive organisms in the primordial environment of the earth evolved spontaneously from inorganic substances and physical forces such, as lightning. UV radiations, volcanic activities, etc.
(ii) Oparin (1924) suggested that the organic compounds could have undergone a series of reactions leading to more complex molecules. He proposed that the molecules formed colloidal aggregates or coacervates. in an aqueous environment. The coacervates were able to absorb and assimilate organic compounds from the environment.
(iii) Haldane (1929) proposed that the primordial sea served as a vast chemical laboratory powered by solar energy. The atmosphere was oxygen free and the combination of `CO_(2), NH_(3)` and UV radiations gave rise to organic compounds.
(iv) The sea became a .hot. dilute soup containing large populations of organic monomers and polymers. They proposed that groups of monomers and polymers acquired lipid membranes and further developed into the first living cell. Haldane coined the term prebiotic soup and this became the powerful symbol of the Oparin-Haldane view on the origin of life (1924-1929).
(v) Oparin and haldane independently suggested that if the perimitive atmosphere was reducing and if there was appropriate supply of energy such as lightning or UV light then a wide range of organic compounds can be synthesized.