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Posted on 02/02/2010 6:40:58 AM PST by decimon
Earth's chemical energy powered early life through 'the most revolutionary idea in biology since Darwin'
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.
"Textbooks have it that life arose from organic soup and that the first cells grew by fermenting these organics to generate energy in the form of ATP. We provide a new perspective on why that old and familiar view won't work at all," said team leader Dr Nick lane from University College London. "We present the alternative that life arose from gases (H2, CO2, N2, and H2S) and that the energy for first life came from harnessing geochemical gradients created by mother Earth at a special kind of deep-sea hydrothermal vent – one that is riddled with tiny interconnected compartments or pores."
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."
In rejecting the soup theory the team 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 giving rise to the first true cells.
The team focused on ideas pioneered by geochemist Michael J. Russell, on alkaline deep sea vents, which produce chemical gradients very similar to those used by almost all living organisms today - a gradient of protons over a membrane. Early organisms likely exploited these gradients through a process called chemiosmosis, in which the proton gradient is used to drive synthesis of the universal energy currency, ATP, or simpler equivalents. Later on cells evolved to generate their own proton gradient by way of electron transfer from a donor to an acceptor. The team argue that the first donor was hydrogen and the first acceptor was CO2.
"Modern living cells have inherited the same size of proton gradient, and, crucially, the same orientation – positive outside and negative inside – as the inorganic vesicles from which they arose" said co-author John Allen, a biochemist at Queen Mary, University of London.
"Thermodynamic constraints mean that chemiosmosis is strictly necessary for carbon and energy metabolism in all organisms that grow from simple chemical ingredients [autotrophy] today, and presumably the first free-living cells," said Lane. "Here we consider how the earliest cells might have harnessed a geochemically created force and then learned to make their own."
This was a vital transition, as chemiosmosis is the only mechanism by which organisms could escape from the vents. "The reason that all organisms are chemiosmotic today is simply that they inherited it from the very time and place that the first cells evolved – and they could not have evolved without it," said Martin.
"Far from being too complex to have powered early life, it is nearly impossible to see how life could have begun without chemiosmosis", concluded Lane. "It is time to cast off the shackles of fermentation in some primordial soup as 'life without oxygen' – an idea that dates back to a time before anybody in biology had any understanding of how ATP is made."
God called for the Earth and the Seas to bring forth life. Thus the Bible is fully consistent with the possibility that God used rational and physical means, utilizing the laws of nature that God himself created; to create life.
I have never understood the “either God did it by magic or there is no need for God” outlook. To me it is the illogical continuation of the “God of the gaps” philosophy.
Oh well then, that settles it, simple as can be. Cells pop into existence, find something to eat and go for domestic over imported victuals. Takes a bit cleverness is all.Having sorted all that out what's next? How climate change acted as the tutor?
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Thanks decimon. |
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We'll never EVER know, so one theory is as good as 'nother.
Oh waiter! There’s a fly in my primordial soup!
Sir Fred Hoyle
Nature, Nov 12, 1981, p. 148
Well thank you for this post, now that the ‘new’ research has decided to cast off ancient theories. But where oh where will this “NEW” knowledge lead these people.... especially since they can’t theorize on what they cannot see.
If that were true then we'd all still be living in caves like SunkenCiv.
There has never been an escape from stalagmite thirteen.
I'm left calcified by your comment.
There would be a lot of empty pages in those textbooks.
“God called for the Earth and the Seas to bring forth life. Thus the Bible is fully consistent with the possibility that God used rational and physical means, utilizing the laws of nature that God himself created; to create life. I have never understood the “either God did it by magic or there is no need for God” outlook.”
Well said. After you get past the fact that God did it, everything else begins to look secondary, at best.
For those of us who adore God as well as perform science, discovering those possible means expands our adoration of God, it does not in any way relegate HIS actions to only that which we cannot explain.
Thanks!
“Well secondary in many respects, but scientifically the primary question is not “did God do it or not” but “how was it accomplished via rational means.”
I think scientists might ultimately disover that everything God does is rational.
“For those of us who adore God as well as perform science, discovering those possible means expands our adoration of God, it does not in any way relegate HIS actions to only that which we cannot explain.”
Not a scientist myself, but I think I see what you mean. Explaining carbohydrate metabolism as a physical process doesn’t mean that God didn’t set it up to run that way.
Many scientists seem to be terrified at the thought of a God who can violate any physical law at will. Or in some cases, perhaps, petulant at the challenge to their own supremacy as the jewel in the crown of evolution.
Scientists are not, on the whole, “terrified” of the idea that God can violate physical laws; most scientists in the USA are people of faith, they simply recognize that such is outside the domain of science.
There is no jewel and no crown in evolution. The idea that evolution ‘perfects’ and that we are somehow the ‘pinnacle’ of evolution is a rather insidious misinterpretation of what the theory entails.
If there is anything at all special about humanity it is not contained within our imperfect physical bodies; but in the immortal soul bequeathed to us by God.
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