Editing Primordial soup (section)

===Heterotrophic theory===

A coherent scientific argument was introduced by [[Soviet Union|Soviet]] biochemist Alexander Oparin in 1924. According to Oparin, in the primitive Earth's surface, [[carbon]], [[hydrogen]], water vapour, and [[ammonia]] reacted to form the first organic compounds. Unbeknownst to Oparin, whose writing was circulated only in Russian, an [[English people|English]] scientist [[J. B. S. Haldane]] independently arrived at a similar conclusion in 1929.<ref name="Oparin">{{Cite web |url=http://breadtagsagas.com/wp-content/uploads/2015/12/AI-Oparin-The-Origin-of-Life.pdf |title=The Origin of Life |last=Oparin |first=Alexander |access-date=2018-10-24 |archive-date=2018-08-22 |archive-url=https://web.archive.org/web/20180822014725/http://breadtagsagas.com/wp-content/uploads/2015/12/AI-Oparin-The-Origin-of-Life.pdf |url-status=live }}</ref><ref>{{Cite web |url=http://www.uv.es/~orilife/textos/Haldane.pdf |title=The Origin of Life |last=Haldane |first=John B. S. |access-date=2018-10-24 |archive-date=2003-09-27 |archive-url=https://web.archive.org/web/20030927095824/http://www.uv.es/~orilife/textos/Haldane.pdf |url-status=live }}</ref> It was Haldane who first used the term "soup" to describe the accumulation of organic material and water in the primitive Earth<ref name=":0" /><ref name="lazcano10">{{cite journal |last1=Lazcano |first1=A. |title=Historical Development of Origins Research |journal=Cold Spring Harbor Perspectives in Biology |date=2010 |volume=2 |issue=11 |pages=a002089 |doi=10.1101/cshperspect.a002089 |pmid=20534710 |pmc=2964185}}</ref>

{{Blockquote |text=When ultra-violet light acts on a mixture of water, [[carbon dioxide]], and ammonia, a vast variety of organic substances are made, including sugars and apparently some of the materials from which proteins are built up. [...] before the origin of life they must have accumulated till the primitive oceans reached the consistency of hot dilute soup. |sign=J. B. S. Haldane |source=The Origin of Life}}

According to the theory, organic compounds essential for life forms were synthesized in the primitive Earth under prebiotic conditions. The mixture of inorganic and organic compounds with water on the primitive Earth became the prebiotic or primordial soup. There, life originated and the first forms of life were able to use the organic molecules to survive and reproduce. Today the theory is variously known as the heterotrophic theory, heterotrophic origin of life theory, or the Oparin-Haldane hypothesis.<ref name="fry">{{cite journal |last=Fry |first=Iris |title=The origins of research into the origins of life |journal=Endeavour |date=2006 |volume=30 |issue=1 |pages=24–28 |doi=10.1016/j.endeavour.2005.12.002 |pmid=16469383}}</ref> Biochemist [[Robert Shapiro (chemist)|Robert Shapiro]] has summarized the basic points of the theory in its "mature form" as follows:<ref>{{cite book |last=Shapiro |first=Robert |title=Origins: A Skeptic's Guide to the Creation of Life on Earth |publisher=Bantam Books |year=1987 |page=[https://archive.org/details/originsskepticsg0000shap/page/110 110] |isbn=0-671-45939-2 |url=https://archive.org/details/originsskepticsg0000shap/page/110 }}</ref>

# Early Earth had a chemically [[reducing atmosphere]].
# This atmosphere, exposed to energy in various forms, produced simple organic compounds ("[[monomer]]s").
# These compounds accumulated in the prebiotic soup, which may have been concentrated at places such as shorelines and [[Hydrothermal vent|oceanic vents]].
# By further transformation, more complex organic [[polymer]]s – and ultimately life – developed in the soup.