for National Geographic News
Long ago, before microbial organisms first took shape as organic cells and began to colonize the biosphere, naked living processes may have commenced within the confines of hollow bubbles of deep-sea rock.
This take on the origins and early stages of biochemistry, laid out in a bold new scientific treatise, could dramatically rewrite the opening chapters of the story of life on Earth. It also implies that extraterrestrial life might exist in much greater abundance that has been traditionally presumed.
"Under our model, you would not need an atmosphere [to foster life]. Rocks and water would be enough," said William Martin of the University of Dusseldorf in Germany.
"Any wet, rocky, sunlit planet will have life," said colleague Michael J. Russell of the Scottish Environmental Research Centre in Glasgow. "It's a matter of course. Life is absolutely inevitable."
If Martin, a biochemist, and Russell, a geologist, are right, then traditional hypotheses about how the Earth's earliest forms of life evolved are due for a rewrite.
The pair has published their far-reaching theory in this month's issue of Philosophical Transactions: Biological Sciences, a journal of the Royal Society of London. The document, at 24 pages, is a hefty and exhaustive tome by the standards of scientific publishing, which can usually pack any idea into six pages or less. But that's because describing early lifelike developing itrequires a bit of time and effort.
A Rocky Start
All living organisms are made up of cellsmembrane-enclosed organic sacksthat contain proteins and strands of genetic material. Without the biological machinery inside, cellular membranes couldn't grow, multiply, or even repair themselves. The most fundamental of life's processes, reproduction, would be inconceivable.
Without the membrane that encloses its fragile components, the molecular machinery of life would be unshielded from the harsh forces of its surrounding environment and would be torn apart before it could do its work. "Life starts with a cell wall or a membrane," Russell said. "Otherwise, it bleeds to death."
What scientists have so far lacked is a convincing explanation for how an organic cell wall could have developed before there was the biological apparatus to build it. And thus arises a vexing microcosmic variation on the chicken-and-egg riddle: Which came first, the apparatus inside, or the membrane that holds each bundle of life together?
Martin and Russell believe they've solved the conundrum by thinking outside the biological box. The first containers of life, they suggest, were themselves neither products nor producers of biochemistry. They were tiny, hollow chambersenveloped by rock.
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