'Primal Soup' Theory Nixed: Earth's Chemical Energy Jump-started Life

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 theory, 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 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 in the seminal essay that appeared in the paper in BioEssays. "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."

Casey Kazan via Wiley-Blackwell

Comments

[Maria Odete Madeira]

Interesting, but it is one more conjectural scenario situated at the level of the processes/effects, but we are still ignorant about the originating causes.

«"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 question is what type of systemic intentionality may be behind this process?

What type of effectiveness is being selected here? In what can this relate to the issue of systemic diversity, linked to the processes of individuation?

Why autonomy? Why the transition for a greater autonomy? Also here there seems to be a missing link, that might help explain things, not from processes/effects but from the causes.

Why something and not nothing?

[SB]

Good point. What was the "Spark" that initiated the "Will" of self preservation evolving into self awareness. Biochemistry alone isn't showing the answer. Non-life does not actively reach out to environment to obtain energy for self preservation. What caused the transition between the passive state of non-life to the active state defining life?

[alexandria heather]

This theory really doesn't nix the concept of 'Soup', it simply provides specific catalysts. There is no doubt of a singular beginning of life. It is only natural that it began from gas/chemical reactions in the ocean...and neutrinos. But they'll wait another 100 years to admit that. Scientist are so backward in ignoring the fact that spirit can be quantified and used mathematically to prove all of the mysteries of life...and death.

[Maria Odete Madeira]

Interesting... "neutrinos" and "spirinos"? Good soup! Who's the cook?

[SB]

"...the fact that spirit can be quantified and used mathematically to prove all of the mysteries of life...and death. ..."

Where can I find the empirical data supporting these facts?

[light]

i second that, where the hell is that data?

yeah and i like the question SB... "What caused the transition between the passive state of non-life to the active state defining life? "

[Maria Odete Madeira]

«What caused the transition between the passive state of non-life to the active state defining life?»

Why passive? Are not forces present? Energy sources, exchanges of energy between open systems,... is not the systemic network computing all this? Where's the passivity?

[SB]

Maria,
Are you sure you understand the difference between "Active" an "Passive"?

[Maria Odete Madeira]

«Are you sure you understand the difference between "Active" an "Passive"?»

Sure,... hmmm... about sure I don't know if I'm sure that I'm sure that I'm sure that I should be sure,... do you care, then, to explain, disambiguate,... since you clearly seem to be very sure. In philosophy one is always open to be enlightened by "sure positions" about the things.

[Iker]

"Why autonomy? Why the transition for a greater autonomy? Also here there seems to be a missing link, that might help explain things, not from processes/effects but from the causes."

I don´t know about the initial autonomy, or "spark" that SB mentioned, but the greater autonomy is in response to the need to fill other niches, since the vents are already occupied. This is a common biological strategy even today.

Good article!

[Maria Odete Madeira]

«I don´t know about the initial autonomy, or "spark" that SB mentioned, but the greater autonomy is in response to the need to fill other niches, since the vents are already occupied. This is a common biological strategy even today.»

So what?

One thing is a survival interface and the effectiveness of adaptive responses to that survival interface, another thing is the issue of the origin of life, and of the definition itself of life. The proposal, addressed in the article, is of a substitution of the "primordial soup" conjecture by "another alternative".

It is not enough to put on the table new conjectures, it is necessary that those conjectures are fundamented, otherwise one is not adding anything, in scientific terms.

Whenever one addresses origins, one is addressing causes and corresponding explanatory reasons, not "post factum" effects and processes.

The point you're raising is a point that is raised after the origins of life. The conjecture advanced in the article misses the link between the before and the after, signalized in terms of autonomy.

Autonomy is about laws/rules, of what laws/rules are we talking about here, in a context of the origin of life problem? What is life? Let’s start by there.

Fundamental questions have to do with fundamental science not applied science, one cannot be addressing origins and be satisfied with analysis of effects that are exhaustively known.

To escape fundamental issues with trivial replies places the question of what sense there is in replying at all.