Claim: Reconstructed ancient ocean reveals secrets about the origin of life
Almost 4 billion years ago life on Earth began in iron-rich oceans that dominated the surface of the planet. An open question for scientists is when and how cellular metabolism, the network of chemical reactions necessary to produce nucleic acids, amino acids and lipids, the building blocks of life, appeared on the scene.
The observed chemical reactions occurred in the absence of enzymes but were made possible by the chemical molecules found in the Archean sea. Finding a series of reactions that resembles the “core of cellular metabolism” suggests that metabolism predates the origin of life. This implies that, at least initially, metabolism may not have been shaped by evolution but by molecules like RNA formed through the chemical conditions that prevailed in the earliest oceans.
So the earliest oceans featured chemical conditions that could somehow result in metabolism without cells?
This would sound more convincing if there were any evidence that it ever happened since.
You’d almost think these people didn’t think they were writing for grownups.
New Scientist picked up the story, but to its credit, quoted,
There is one big problem, however. “For origins of life, it is important to understand where the source molecules come from,” Powner says. No one has yet shown that such substances could form spontaneously in the early oceans.
A related issue is that the reactions observed so far only go in one direction; from complex sugars to simpler molecules like pyruvate. “Given the data, one might well conclude that any organics in the ocean would have been totally degraded, rather than forming the basis of modern metabolism,” says Jack Szostak, who studies the origin of life at Harvard. “I would conclude that metabolism had to evolve, within cells, one reaction and one catalyst at a time.”
Does he mean that it was the same back then as in the real world we know today?
See also: The Science Fictions series at your fingertips (origin of life) for a quick handy explanation of why this stuff is given any attention at all.
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