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.
You younguns will just have to wait to enjoy all the fun benefits of hitting 60...oh, wait...what were those benefits again?
Well, it sure isn't the failing eyesight or aching muscles and joints or the memory lapses when you forget the name of the person you're talking to when you've known them for years or...
"If fitness is correlated with survival and reproduction, then how can it not apply to individuals. It seems to me, this would be it's primary concern. "
A simple thought experiment: If you are the fittest possum ever and you choose to cross the highway during rush hour - what are you? ROADKILL
But if there's a subpopulation just like you, eventually all possums will be like you.
Sweet Dreams :-)
Well, how on earth can I argue with someone who won't even acknowledge it's existence.
Maybe someday soon we'll know. But there are lots of cases where people don't pass on their genes -- suicides, for instance. And yet selection is still at work.
And doesn't that give you pause for thought.
If natural selection can accommodate any outcome: survival, perishment, reproduction, reproductive stasis...then in what way is it useful (let alone practical for a scientific theory) if it is not falsifiable.
I did see the correction reading through the posts and thanks for the link.
Homosexuality exists, but what exactly is it? What is the precise trigger that determines sexual attraction? You don't know, I don't know, and until we know, it is impossible to say with certainty how and why it exists.
And doesn't that give you pause for thought.
No. The genes of individuals who for whatever reason do not reproduce are not passed on to subsequent generations. So on the contrary, that's classic selection. If every individual reproduced succesfully, there would be no selection and then, indeed, evolutionary theory would be invalidated.
But if there's a subpopulation just like you, eventually all possums will be like you.
Sweet Dreams :-)
I see, so natural selection doesn't make sense if an individual possum wonders in the road and gets squashed, but it does if all the possums wonder in the road and get squashed, regardless if they did it individually or not...
I get it now...I think.
Sweet Dreams :-)
Easy for you to say. What if I have nightmares...oh wait, that's right, I'm an individual so it wouldn't count....never mind.
You're free to speculate about such things, but they're simply irrelevant to the argument at hand. Correlated with reproduction, I think the terms are quite clear.
No. The genes of individuals who for whatever reason do not reproduce are not passed on to subsequent generations. So on the contrary, that's classic selection. If every individual reproduced succesfully, there would be no selection and then, indeed, evolutionary theory would be invalidated.
let me see if I understand you correctly. If those in a given population, who can reproduce, do reproduce...then evolution would be falsified?
Not quite. If every individual in a generation passed on its genes, then that would falsify a substantial part of evolutionary theory. It would not falsify evolution.
Population, of course, not generation.
If this theory is true then there should be plenty of real life samples that scientists can collect from the clay based soil surrounding any of the volcanic fissures on the planet today....hooray...the mystery is solved by science...when a scientist provides an actual example i will be convinced...in the mean time i will hold my breath...just tell them to hand the sample to the blue faced guy in the corner when it is ready.
From now on, everything I do that I haven't done for the past 5 years is going to be "the ___ of the century!"
sounds good, but there are a few problems with your statement...one...if there are organisms today that are ready to devour any organic matter that forms, by your own admission there are organisms today that rely at least in part on this organic matter...ie....it still is being produced. your argument that early clay life cannot exist because it was at the bottom of the food chain doesn't hold water either...following your logic, there would be no examples of simple life forms available today because bigger...more evolved predators would have eaten them all. Also, if all the proteins that existed back then ate all of the complex clay molecules, how did they survive after that?
AND WE THINK YOU GUYS HAVE mAXWELL'S!
CAPSlock key for sale
Used only invertedly.
(I'll bet that they all share many of the same DNA sequences. ;^)
Proper credentials ARE a requirement, it seems.
Then ya gotta walk a mile....
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