Ero sivun ”Käyttäjä:Dodi 8238/Elämän alkuperä” versioiden välillä

==="Primordial soup" hypothesis===

{{anchor | Haldane and Oparin: The Primordial Soup Theory}}<!--This section is linked from [[:en:The Selfish Gene]]-->

{{further2|[[:en:Miller–Urey experiment]]}}

No new notable research or theory on the subject appeared until 1924, when [[:en:Alexander Oparin]] reasoned that atmospheric oxygen prevents the synthesis of certain organic compounds that are necessary building blocks for the evolution of life. In his book ''The Origin of Life'',<ref>{{harvnb|Bernal|1967|loc=[http://www.valencia.edu/~orilife/textos/The%20Origin%20of%20Life.pdf ''The Origin of Life'' (A. I. Oparin, 1924), pp. 199–234]}}</ref><ref>Oparin: ''The Origin of Life''.</ref> Oparin proposed that the "spontaneous generation of life" that had been attacked by Louis Pasteur did in fact occur once, but was now impossible because the conditions found on the early Earth had changed, and preexisting organisms would immediately consume any spontaneously generated organism. Oparin argued that a "primeval soup" of organic molecules could be created in an oxygenless atmosphere through the action of [[:en:sunlight]]. These would combine in ever more complex ways until they formed [[:en:coacervate]] droplets. These droplets would "[[:en:cell growth|grow]]" by fusion with other droplets, and "[[:en:reproduction|reproduce]]" through fission into daughter droplets, and so have a primitive [[:en:metabolism]] in which factors that promote "cell integrity" survive, and those that do not become extinct. Many modern theories of the origin of life still take Oparin's ideas as a starting point.