OparinHaldane

The Oparin-Haldane hypothesis, independently proposed by Alexander Oparin in 1924 and J.B.S. Haldane in 1929, is a foundational theory in the study of the origin of life. It suggests that life arose gradually from inorganic molecules through a series of progressive chemical reactions in the early Earth's primordial environment.

According to the hypothesis, the early Earth's atmosphere lacked free oxygen and was rich in gases like methane, ammonia, water vapor, and hydrogen. Energy sources such as ultraviolet radiation from the sun and lightning discharges would have provided the necessary impetus for these simple inorganic molecules to react and form more complex organic compounds. These organic molecules, including amino acids, nucleotides, and simple sugars, are the building blocks of life.

The hypothesis further proposes that these organic molecules accumulated in the early oceans, forming a "primordial soup." Within this soup, further chemical reactions and self-assembly processes led to the formation of larger, more complex structures such as protocells or coacervates. These primitive entities would have possessed some basic characteristics of life, such as a boundary separating their internal environment from the external one, and the ability to carry out simple metabolic processes. Over vast periods, these protocells would have evolved through natural selection, eventually leading to the first true living organisms.

The Oparin-Haldane hypothesis has been significantly influential, inspiring experimental work like the Miller-Urey experiment, which successfully demonstrated the abiotic synthesis of amino acids under simulated early Earth conditions, lending empirical support to the core ideas of the hypothesis.