Chemical Evolution of Life (Self-Assembly Theory)

Unlike the theories in the previous section, the self-assembly (or biochemical) theory of the origin of life offers a testable, chemistry-based explanation: it proposes that life originated on Earth through combinations of several chemicals reacting with one another repeatedly over an immense span of time. First floated in outline by Ernst Haeckel, the idea was developed into a proper scientific theory by the Russian biochemist Alexander I. Oparin (1924) and, independently, by the British biologist J. B. S. Haldane (1929) — which is why it is often called the Oparin-Haldane theory. Both proposed that chemical evolution proceeded through a definite sequence of stages, from the formation of Earth's earliest atmosphere …