  "primordial soup" is a term introduced by the soviet biologist alexander oparin. in 1924, he proposed a theory of the origin of life on earth through the transformation, during the gradual chemical evolution of molecules that contain carbon in the primordial soup. biochemist robert shapiro has summarized the "primordial soup" theory of oparin and haldane in its "mature form" as follows: # early earth had a chemically reducing atmosphere. # this atmosphere, exposed to energy in various forms, produced simple organic compounds ("monomers"). # these compounds accumulated in a "soup", which may have been concentrated at various locations (shorelines, oceanic vents etc.). # by further transformation, more complex organic polymers â and ultimately life â developed in the soup. ==a reducing atmosphere== whether the mixture of gases used in the millerâurey experiment truly reflects the atmospheric content of early earth is controversial. other less reducing gases produce a lower yield and variety. it was once thought that appreciable amounts of molecular oxygen were present in the prebiotic atmosphere , which would have essentially prevented the formation of organic molecules; however, the current scientific consensus is that such was not the case. (see oxygen catastrophe). ==monomer formation==  one of the most important pieces of experimental support for the "soup" theory came in 1953. a graduate student, stanley miller, and his professor, harold urey, performed an experiment that demonstrated how organic molecules could have spontaneously formed from inorganic precursors, under conditions like those posited by the oparin-haldane hypothesis. the now-famous "millerâurey experiment" used a highly reduced mixture of gases&mdash;methane, ammonia and hydrogen&mdash;to form basic organic monomers, such as amino acids. this provided direct experimental support for the second point of the "soup" theory, and it is around the remaining two points of the theory that much of the debate now centers. apart from the millerâurey experiment, the next most important step in research on prebiotic organic synthesis was the de
Evolutionarily_significant_biological_phenomena Evolutionary_biology Origin_of_life