COSMIC EVOLUTION OF THE BIOGENIC ELEMENTS AND COMPOUNDS

This paper traces the evolution of the biogenic elements H, C, N, O, P and S from their creation by cosmic nucleosynthesis to their inclusio n in living systems on the surface of the Earth. Evidence for the pres ence of significant prebiotic molecules in interstellar clouds and in primitive meteorites is reviewed. The possible relevance of this disco very to the origin of life on Earth is assessed in the light of eviden ce suggesting that such molecules could not easily be synthesized in a primitive CO2-dominated terrestrial atmosphere.