Is there a single origin of life?
The emergence of the first life on the earth is now established as an early event, and closely related to the evolving earth. Laboratory experiments examining possible chemical events have revealed a multitude of plausible pathways. Lack of knowledge of the primitive terrestrial conditions contemporary with the evolving prebolic organic chemistry limits reconstruction techniques. The primitive earth's aqueous history is essential to unraveling this problem. Based on our current knowledge of other planets of the solar system, we do not expect close analogues to the early earth.  We still do not know if there was a second origin or if only earth has life. This may depend upon the question of the survival of information bearing chemical systems in a dynamic or chaotic environment and the chemical protection afforded within such a system. Water is the central molecule of controversy: the blessing and the curse of the chemist. New and novel chemical mechanisms and systems abound.
Soffen
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NASA/Goddard Space Flight Center, Space and Earth Sciences Directorate, Greenbelt, MD 20771, USA.
D004798:Enzymes / Q000737:chemistry; D019418:Evolution, Chemical; D019143:Evolution, Molecular; D019419:Evolution, Planetary; D009696:Nucleic Acids / Q000737:chemistry; D000069497:Origin of Life; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D004798:Enzymes; D009696:Nucleic Acids; D014867:Water