Remember the “undersea volcanic vents” origin of life?
|April 10, 2014||Posted by News under News, Origin Of Life|
Black smokers. White smokers.
Superb pix. It has to be true for that reason alone, says the photo editor.
Well, from ScienceDaily:
In 1977, scientists discovered biological communities unexpectedly living around seafloor hydrothermal vents, far from sunlight and thriving on a chemical soup rich in hydrogen, carbon dioxide, and sulfur, spewing from the geysers. Inspired by these findings, scientists later proposed that hydrothermal vents provided an ideal environment with all the ingredients needed for microbial life to emerge on early Earth. A central figure in this hypothesis is a simple sulfur-containing carbon compound called “methanethiol” — a supposed geologic precursor of the Acetyl-CoA enzyme present in many organisms, including humans. Scientists suspected methanethiol could have been the “starter dough” from which all life emerged.
The theory was appealing, and solved many of the basic problems with existing ideas that life may have been carried to Earth on a comet or asteroid; or that genetic material emerged first — the “RNA World” hypothesis. However, says Reeves, “it’s taken us a while to get out there and actually start to test this ‘metabolism first’ idea in the natural environment, by using modern vents as analogs for those that were around when life first began.”
You’d mostly never have known those “basic problems” existed if a model with different basic problems was not being flogged.
Anyway, some jokers decided to test the model:
Instead of an abundance of methanethiol, the data they collected in the hydrogen-rich environments showed very little was present. “We actually found that it doesn’t matter how much hydrogen you have in black smoker fluids, you don’t seem to be making a lot of methanethiol where you should be making a lot of it,” Reeves says. Surprisingly, in the low-hydrogen environments, where much less should form, the research actually found more methanethiol than they had predicted, contradicting the original idea of how methanethiol forms. Overall, this means that jump-starting proto-metabolic reactions in hydrogen-rich early Earth hydrothermal systems through carbon-sulfur chemistry would likely have been much harder than many had assumed.
Critically, the researchers found an abundance of methanethiol being formed in low temperature fluids (below about 200̊C), where hot black smoker fluid mixes with colder sea water beneath the seafloor. The presence of other telltale markers in these fluids, such as ammonia — a byproduct of biomass breakdown — strongly suggests these fluids are ‘cooking’ existing microbial organic matter. The breakdown of existing subseafloor life when conditions get too hot may therefore be responsible for producing large amounts of methanethiol.
“What we essentially found in our survey is that we don’t think methanethiol is forming by purely chemical means without the involvement of life. This might be disappointing news for anyone assuming an easy start for hydrothermal proto-metabolism,” says Reeves. “However, our finding that methanethiol may be readily forming as a breakdown product of microbial life provides further indication that life is present and widespread below the seafloor and is very exciting.”
They hope it will help in the search for extraterrestrial life. That is, it didn’t pan out in a life-friendly environment, but might work in a challenging one elsewhere.
As noted earlier, origin of life is a problem in the origin of huge amount of information and looking for a way it happened due to some fluke has always been a waste of time.
Software engineer Arminius Mignea’s specifications for a simplest self-replicator in Engineering and the Ultimate would be a useful read on that score. It advances the discussion by setting out what origin of life (by human or other hands) models should look like, to merit consideration.
Too often, people play rhetorical games that sound like: “Life happened, so my ‘stink world’ is plausible” or “The prevailing consensus says Stink World is plausible, therefore life.”
It’s a form of homage to philosophical materialism, not science really, and it suck in lots of well-meaning people. They don’t realize that when we are asked to accept an inherently implausible idea because it is materialist, we are invited to put materialism above every other consideration, including logic, reason, and evidence.
See also: The Science Fictions series at your fingertips (origin of life)
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Bill Nye, five years ago, on the vents:
See also: Timothy Kershner at ID Facebook page