Chemical theory of evolution is a hypothesis that tries to explain the origin of life on Earth. It suggests that life began as a result of chemical reactions that occurred spontaneously in the environment. The theory was first proposed by a Russian biochemist named Aleksandr Ivanovich Oparin in 1924.
Oparin’s theory postulated that the early Earth’s atmosphere was reducing, which means it had little or no oxygen. This type of environment would have allowed for the formation of organic molecules from simple inorganic compounds such as water, carbon dioxide, and ammonia. Oparin believed that these organic molecules could have combined to form more complex molecules, eventually leading to the formation of life.
Oparin’s theory gained popularity after experiments performed by American chemist Stanley Miller and Harold Urey in 1953. The Miller-Urey experiment simulated conditions thought to exist on early Earth by combining water, methane, ammonia, and hydrogen in a closed system and then subjecting them to electric sparks. After one week of continuous sparking, they found several amino acids had formed.
The idea behind the Chemical Theory of Evolution has since been developed and refined over time with contributions from several scientists. One such scientist was Sidney W. Fox who proposed that proteinoid microspheres could form under certain conditions from mixtures of amino acids.
Another notable contribution came from Carl Sagan, who suggested that life on Earth may have been seeded by organic molecules brought here by comets or meteorites.
In conclusion, while many scientists have contributed to the development and refinement of the Chemical Theory of Evolution over time, it was originally proposed by Aleksandr Ivanovich Oparin in 1924. His hypothesis has laid the foundation for our understanding of how life may have emerged on Earth through purely chemical means.