Who proposed the chemical evolution of life?

A.I. Oparin proposed the theory of chemical evolution of life in his 1924 book 'The Origin of Life'. His hypothesis suggested that organic molecules could form from inorganic precursors under early Earth conditions, eventually leading to primitive cells. Darwin proposed biological evolution by natural selection, Lamarck proposed inheritance of acquired characteristics, and Haeckel proposed recapitulation theory - none addressed chemical origins.