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.
Origen is generally considered Mr. Allegorical interpretation but that is really too simple an explanation. He "granted to them a sophistication of intention and composition which rose beyond the simple dichotomies of literal and symbolic.."
or so says the instructor of my creation class.
Would Origenalist Judges take the Constitution as allegory? (Or allergy?)
So it's really more like "You kids get off my floe!" then...
Origen is generally considered Mr. Allegorical interpretation but that is really too simple an explanation.
Huh? What? I'm not familiar with Mr. Allegorical.
It's been a long time since I've had evolution so my memory on the order of it is somewhat foggy.
So the fossil record shows that mammals appeared before birds, if I read that correctly?
What are mammal-like reptiles? IOW, How is a reptile mammal-like?
Did mammals and dinosaurs evolve from a common ancestor or are mammals considered a branch off of dinosaurs and where do birds fit in? Because of their egg laying, I would presume that it's thought that they decended from reptiles, correct? I've seen a diagram called the web of life or tree of life on other threads but couldn't find anything useful when I tried googling it. There's just way too much info out there and I wasn't sure where to start.
That would be this guy:
I explained the stumbling block idea in post 155. It's a reference to Origen.
That would then make spontaneous generation an unfalsifiable theory. It should therefore be rejected immediately as unscientific.
This is faintly ridiculous. If life were such a foregone conclusion, then we should have been able to create it long before now. I mean, we have the finished product available everywhere for study and the reverse engineering is pretty straightforward for the simplest bacterial cells. We know pretty much all the important chemicals and how they're put together. Quit worrying about what the primordial Earth was like and just create the optimal conditions in the laboratory and create self-replicating molecules that you then guide with artificial speed into bacteria. Create the life, already, then worry about finding the mechanism that was in place on the primordial Earth.
Oh, wait. Even with everything we know about biochemistry, and the ability to create the perfectly optimized lab conditions we still can't create spontaneously forming complex organic, self-replicating, information carrying moleules. So instead, we'll get grant money for red herring experiments where we'll cook methane in a clay matrix to make hydrocarbon chains and ignore all the organic chemistry professors that look at us and say: Well, duh, what did you expect?
Have you not seen the beauty of lichen covered tundra?
I'm done for the night.
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.
Ants and bees seem to do quite well with over 99% of the individuals being sterile.
Your analogy might have some bearing on the conversation if it was also the case that in human populations, one percent gave birth to the other ninety nine.
Individual homosexuals may not have their genes passed on but that has no more bearing on human evolution than the failure of many heterosexuals to bear children.
Well, I obviously disagree.
I explained the stumbling block idea in post 155. It's a reference to Origen.
IOW, we're mice in a maze. Thanks for clearing that up.
I don't explain homosexuality. I've seen attempts to explain homosexuality through evolutionary mechanisms, but since nobody has shown with any certainty what exactly homosexuality is, I think it's really just conjecture. 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.
I've always had more trouble when I lived in an area with a high clay content. The soil gets packed so hard when it gets a little dry, it's almost impossible to cultivate and weed. You almost need a sledge hammer to break it up.
Dang! I knew the muslims were trying to take over Europe and it looks like Europe gets assimilated.
Party pooper!
It actually seems that there is some pretty advanced writing styles in the Bible. While it was written many years ago, it does not fit with what I would expect to read if the authors were that primitive or uneducated.
So the fossil record shows that mammals appeared before birds, if I read that correctly?
What are mammal-like reptiles? IOW, How is a reptile mammal-like?
Did mammals and dinosaurs evolve from a common ancestor or are mammals considered a branch off of dinosaurs and where do birds fit in? Because of their egg laying, I would presume that it's thought that they decended from reptiles, correct? I've seen a diagram called the web of life or tree of life on other threads but couldn't find anything useful when I tried googling it. There's just way too much info out there and I wasn't sure where to start.
This is way past my expertise--my studies were all on the more recent end of things. I did a quick google and picked out the highlights to answer the questions, but did not verify the information.
And one of the things I found has already been corrected, so there you go.
There should be some websites out there that will give you what you need. As a start try here: http://en.wikipedia.org/wiki/Mammal.
If you need more, just ask and someone should be able to help.
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