1. Primordial Soup Theory
The Primordial Soup Theory, proposed by Alexander Oparin and J.B.S. Haldane in the 1920s, suggests that life originated in Earth’s early oceans from simple organic compounds. (en.wikipedia.org) These compounds formed through chemical reactions among gases like methane, ammonia, and hydrogen, energized by lightning or ultraviolet light. (olhardigital.com) The 1953 Miller-Urey experiment provided experimental support by demonstrating that amino acids could form under such conditions. (en.wikipedia.org)