ScienceDaily (Feb. 3, 2010) — For 80 years it has been accepted that early life began in a 'primordial soup' of organic molecules before evolving out of the oceans millions of years later. Today the 'soup' theory has been over turned in a pioneering paper in BioEssays which claims it was the Earth's chemical energy, from hydrothermal vents on the ocean floor, which kick-started early life.
In rejecting the soup theory the researchers turned to the Earth's chemistry to identify the energy source which could power the first primitive predecessors of living organisms: geochemical gradients across a honeycomb of microscopic natural caverns at hydrothermal vents. These catalytic cells generated lipids, proteins and nucleotides which may have given rise to the first true cells. (Credit: Photograph by Dudley Foster from RISE expedition, courtesy of William R. Normark, USGS)
The soup theory was proposed in 1929 when J.B.S Haldane published his influential essay on the origin of life in which he argued that UV radiation provided the energy to convert methane, ammonia and water into the first organic compounds in the oceans of the early earth. However critics of the soup theory point out that there is no sustained driving force to make anything react; and without an energy source, life as we know it can't exist.
"Despite bioenergetic and thermodynamic failings the 80-year-old concept of primordial soup remains central to mainstream thinking on the origin of life," said senior author, William Martin, an evolutionary biologist from the Insitute of Botany III in Düsseldorf. "But soup has no capacity for producing the energy vital for life."
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Problems and paradigms
How did LUCA make a living? Chemiosmosis in the origin of life
Nick Lane 1, John F. Allen 2, William Martin 3 *
1Department of Genetics, Evolution and Environment, University College London, London, UK
2School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
3Institut für Botanik III Heinrich-Heine-Universität, Düsseldorf, Germany
email: William Martin (w.martin@uni-duesseldorf.de)
*Correspondence to William Martin, Institut für Botanik III Heinrich-Heine-Universität, Universitätsstr. 1, 40225 Düsseldorf, Germany.
KEYWORDS
alkaline hydrothermal vents • ATPase • chemiosmosis • LUCA • proton gradients
ABSTRACT
Despite thermodynamic, bioenergetic and phylogenetic failings, the 81-year-old concept of primordial soup remains central to mainstream thinking on the origin of life. But soup is homogeneous in pH and redox potential, and so has no capacity for energy coupling by chemiosmosis. Thermodynamic constraints make chemiosmosis strictly necessary for carbon and energy metabolism in all free-living chemotrophs, and presumably the first free-living cells too. Proton gradients form naturally at alkaline hydrothermal vents and are viewed as central to the origin of life. Here we consider how the earliest cells might have harnessed a geochemically created proton-motive force and then learned to make their own, a transition that was necessary for their escape from the vents. Synthesis of ATP by chemiosmosis today involves generation of an ion gradient by means of vectorial electron transfer from a donor to an acceptor. We argue that the first donor was hydrogen and the first acceptor CO2.
DIGITAL OBJECT IDENTIFIER (DOI)
10.1002/bies.200900131
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NOTA IMPERTINENTE DESTE BLOGGER:
Eu destaco a introdução inusitada feita pelos autores deste artigo:
Despite thermodynamic, bioenergetic and phylogenetic failings, the 81-year-old concept of primordial soup remains central to mainstream thinking on the origin of life.
Traduzindo em graúdos:
Apesar dos fracassos termodinâmicos, bioenergéticos e filogenéticos, o conceito de 81 anos da sopa primordial permanece central para o pensamento corrente sobre a origem da vida.
Esta introdução, ou será que foi uma confissão, denúncia pra deixar todo mundo revoltado sobre como a ciência vem sendo feita nesta área: motivada mais por uma agenda ideológica do que seguir as evdências aonde elas estiverem nos levando...
Alô MEC/SEMTEC/PNLEM, não dá mais pra continuar engabelando os alunos do ensino médio com livros didáticos de Biologia. Os autores sabiam há muito tempo que a tal de 'sopa primordial' química sequer deixou evidências geológicas, mas o 'mito' da evolução química para explicar a origem da vida era fundamental para poder ensinar a evolução biológica.
Fui, sem saber por que, pensando na cara de Darwin que sonhava por um lago morno onde o mito pudesse se transformar em uma verdade científica. Darwin, meu nego, você quebrou a cara, pois o Mysterium tremendum continua Mysterium tremendum!!!
