Posted on 11/04/2005 5:00:06 AM PST by PatrickHenry
Minerals help molecules thought to have been essential for early life to form.
A team of US scientists may have found the 'primordial womb' in which the first life on Earth was incubated.
Lynda Williams and colleagues at Arizona State University in Tempe have discovered that certain types of clay mineral convert simple carbon-based molecules to complex ones in conditions mimicking those of hot, wet hydrothermal vents (mini-volcanoes on the sea bed). Such complex molecules would have been essential components of the first cell-like systems on Earth.
Having helped such delicate molecules to form, the clays can also protect them from getting broken down in the piping hot water issuing from the vents, the researchers report in the journal Geology [Williams L. B., et al. Geology, 33. 913 - 916 (2005).].
"It's very interesting that the clays preserve them," says James Ferris, a specialist on the chemical origins of life at Rensselaer Polytechnic Institute in Troy, New York. "It shows that this could be an environment where complex organic molecules can be formed."
Some like it hot
Hydrothermal vents are created when seawater that has seeped through cracks in the seafloor is heated by magma just below the surface. The water streams back out of the rock in a plume that can reach temperatures of around 400 °C.
Vents are a favourite candidate for the site where life first appeared. Their heat provides an energy source; the minerals provide nutrients; and the deep-sea setting would have protected primitive organisms from the destructive meteorite impacts that scoured the planet's surface early in its history.
But researchers have long wondered how, if early life did form in this environment, it escaped being boiled and fried by the harsh conditions.
The Arizona State team has shown that clay minerals commonly found at vents can encase organic molecules, keeping them intact.
Between the sheets
The group simulated the vent environment in the laboratory, immersing various types of clay in pressurized water at 300 °C for several weeks and looking at the fate of a simple organic compound, methanol, in this stew. They chose methanol because their earlier work had shown that the compound could be formed in a vent environment from simple gases such as carbon dioxide and hydrogen.
Clays generally consist of sheets made of aluminium, silicon and oxygen atoms, which are stacked on top of one another. In some of these materials, such as the clays saponite and montmorillonite, there is room for other atoms and molecules to slip between the layers.
Spouting soup
The researchers found that the methanol in their artificial vent system was converted to various large organic molecules over six weeks or so, so long as the clay's layers were spaced widely enough to hold the compounds.
"The clay provides a safe haven for the organic molecules, essentially like a 'primordial womb'," the team reports. Eventually, changes in the clay's mineral structure caused by heat, pressure and time may cause the sheets to close up and expel the molecules inside. But they think that some of these could spout out from the clay into less hostile environments than the hottest part of the vent, creating an organic soup in which life might arise.
These findings add weight to the idea that clays were the key to the origin of life. Previous research has shown that clays act as catalysts for the formation of polymer molecules such as the precursors of proteins and DNA. They can also encourage lipid molecules to arrange themselves into cell-like compartments called vesicles.
Actually, there is a fossil of a snake with legs. It was written up in 2000. Here's a link to a page, describing it:
http://www.karencarr.com/News/legs/legged_snake.htm
I probably don't have twenty years to wait.
"I probably don't have twenty years to wait."
Well, there is that. At 60, I don't know if I do, either, but it's something to look forward to.
Keep in mind that LeMaitre (the priest you speak of) didn't have any physical evidence to back his claims. It wasn't until Edwin Hubble discovered the universe was expanding (a mere two years later) that the idea began to receive vindication. Extraordinary claims require extraordinary evidence, and Hubble found it. If we had accepted LeMaitre's claim without evidence, it would have been a leap of religious faith.
Amazing link; thanks.
That may still be truly random, only that the underlying distribution isn't uniform. Having a uniform distribution isn't all that important as the distribution may be changed by looking at things differently.
For example; atoms undergoing radioactive decay have a uniform probablity for within a given time interval is constant (depending on the length of the interval, not the starting point of the interval); however, the waiting time for an atom to decay is exponentially distributed. The number of atoms decaying in an interval is Possionly distributed.
It's not a big point, but I have seen some papers by economists who think only a Normal distribution is random or some who think only a uniform distribution is normal.
What's Normal for one may be Poisson to another.
Ironic!
ROTFLMAO!
Let me be clear. I do not reject the idea that life came from "inanimate" matter. Because "inanimate matter" is nothing like what Lucretius imagined, images which was incorporated into the early atomic theory. What it "is" we do not know. What we do know that that it is not "dead" and if not "alive," then dynamic--and elusive.
Sorry you got jumped on and glad you posted the info.
I cut my science-loving teeth on "Micobe Hunters" which covered this with fairly florid prose and I particularly relished the back-and-forth of the early experiments.
Thanks for the nostalgia trip.
Clay has been under suspicion as significant in biogenesis since at least 1966.
The earliest transitional shows mammal-like fossils just before the Permian extinction ~250Mya.
Some of those survived into the Triassic -- as did some of the reptiles that went on to become dinosaurs and then avians.
Although birds reached a more or less modern form first, proto-mammal showed up before the proto-bird.
I'm going to have to apologise for misreading your motives. It seems like nearly evo thread has someone post a story about Pasteur as a refutation of evolution. Some of are pretty tired of this.
The history of vitalism and spontaneous generation are fascinating when put in perspective and context. It's just that they have no direct bearing on current research.
I think it was less a leap of faith than a conclusion drawn from from calculations and observation.
Well, roughly 60 years ago, that's precisely what got me fired up about doing experiments to find out things.
(Yeh, I'm -that- old.)
I'm not happy with your choice of words. Selection is not purposive in the usual sense of the word. It doesn't have a goal or direction. It's a difficult distinction and one that seems to elude understanding, just as the invisible hand of economics eludes easy understanding.
My son had a junior high science teacher who asserted that snakes don't have bones. Needless to say, she did not teach anything about evolution.
And this can be repeated over and over and over.....
The odd thing about science is that first impressions fade away with evidence. The details of the big bang are still under investigation, but the event was accepted as soon as the evidence appeared.
Same with evolution. It is the hyperliteral interpreters of the Bible who have not accepted the big bang.
I was the first to jump, and I've apologized. I'm tired, though, of posters asserting that Pasteur disproved abiogenesis.
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