Saturday, April 26, 2014

The Swirl Of Life?

Posted in Friday's New Scientist is an article that describes the recent - and serendipitous - discovery of how life might have formed without the presence of cells in Earth's early oceans.
Ralser's team took early ocean solutions and added substances known to be starting points for modern metabolic pathways, before heating the samples to between 50˚C and 70˚C – the sort of temperatures you might have found near a hydrothermal ventMovie Camera – for 5 hours. Ralser then analysed the solutions to see what molecules were present. 
"In the beginning we had hoped to find one reaction or two maybe, but the results were amazing," says Ralser. "We could reconstruct two metabolic pathways almost entirely." 
The pathways they detected were glycolysis and the pentose phosphate pathway, "reactions that form the core metabolic backbone of every living cell," Ralser adds. Together these pathways produce some of the most important materials in modern cells, including ATP – the molecule cells use to drive their machinery, the sugars that form DNA and RNA, and the molecules needed to make fats and proteins. 
If these metabolic pathways were occurring in the early oceans, then the first cells could have enveloped them as they developed membranes. 
In all, 29 metabolism-like chemical reactions were spotted, seemingly catalysed by iron and other metals that would have been found in early ocean sediments. The metabolic pathways aren't identical to modern ones; some of the chemicals made by intermediate steps weren't detected. However, "if you compare them side by side it is the same structure and many of the same molecules are formed," Ralser says. These pathways could have been refined and improved once enzymes evolved within cells.
And, quite obviously, have provided the mechanism for the evolutionary development of more complex cellular structures.

Those who argue against the Theory of Evolution like to declare that the theory can't be proven.  Absent a working two-way time machine, this is almost certainly true ... and entirely beside the point behind the theory in dispute as well as Rene Descartes's Scientific Method itself.  It is not the intent to prove how something did happen, only how it could.  The demonstration of possibility is sufficient to justify further experimentation.  At some point, the preponderance of the experimental results will (or will not) demonstrate the reproducibility of the theory - and thereby render a measure of likelihood regarding the outcome.

Faith leaps from assertion to certainty instead.

I like reading these sort of discoveries because they make clear how little we know about what we experience in life.  Claiming to already know the answers, but not being able to "show your work", seems boring and dismissive to me.  Pursuing discovery through doubt and uncertainty seems much more life-like to me.

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