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.
Random selection? Random selection? What the heck is random selection?
It IS an interesting choice of words. All through Genesi 1 it's "Let there be.." Sometimes it's followed by, "and it was so" and sometimes it's followed by "God made" or "God created". I don't know Hebrew so don't understand the distinction between the words. It seems that sometimes He spoke and it happened and other times He was active in creating.
I always understood that it was the universe that was created Ex nihilo, not man.
Mutation itself isn't truly random. It occurs more frequently in some parts of the genome than in others. More pseudo-random than strictly random.
I believe you are missing the point of what I said. There are definite cases where evolutionary theory has had success in its explanatory power and been tested empirically. There is plenty we still don't know - the scientific response to these situations is "we don't know". We search for naturalistic explanations because there is no way to test for non-naturalistic explanations.
The problem with ID is that there is no way to empirically tell the difference between an "irreducibly complex" mechanism and a mechanism that evolved naturally but we have no idea how yet. Many mechanisms that were once believed to be irreducibly complex (i.e. the vertebrate eye) now have very feasible evolutionary explanations. This does not mean that ID is wrong (it impossible to prove ID wrong), but it does mean that it isn't science.
The search for undiscovered naturalistic explanations is not an exercise in faith, it is merely an exercise of the scientific method and realization of the limits of science.
Yep thats what I was taught.
The Big Bang theory certainly seems to lend credence to that view.
You might want to check with Coyoteman about this, as he is a resident bones expert, but I believe the fossil record supports birds first, then mammals.
(Coyoteman pinged as a courtesy since I mentioned his name)
"But I am still waiting for scientists to offer a mechanism for spontaneous generation. "
Keep waiting. I predict that your wait will end within 20 years.
My point is that God has told us about creation and many of us insist on making up our own stories.
A quick google shows:
The first mammals appeared about 265 million years ago, a mere 10 million years after the first dinosaurs
Archaeopteryx is considered by many to be the first bird, being of about 150 million years of age
what do you mean by "random selection"?
I am familiar with random mutation, and environmental (and other) selective pressures - which are not entirely unpatterened - but not "random selection"
I don't believe I have ever seen "random selection" described by an evolutionary scientist, geneticist, or biologist as part of the process of heritance and speciation.
please, by all means, explain: what exactly do you believe "random selection" means?
"My point is that God has told us about creation and many of us insist on making up our own stories."
Which god would that be? Every religion has creation stories involving deities.
But but but but but but but the Earth is only 6000 years old......
/sarcasm off/
"I always understood that it was the universe that was created Ex nihilo, not man.
The Big Bang theory certainly seems to lend credence to that view."
Yes and the Catholic priest who proposed it was accused of injecting religion into science.
Snakes are indeed a fragile specimen when it comes to preserving their skeletons. They have no prominent skeletal system beyond the vertebra. Their ribs are very delicate. And as their skulls are held together by muscles and ligaments, which is what allows it to be flexible enough to allow the snake to swallow its prey whole, they tend to fall apart rapidly upon death. This certainly means a frustratingly patchy fossil record of their ancestry.
However, enough is known from the snake fossils that do exist to give a good idea of their general development. A good summary of this can be found here.
The exact lineage of the earliest snakes is a subject of debate. However, a common point among possible theories is that they originally evolved either directly from early lizards or shared a close common ancestor to them. Some features of living snakes, such as boas and pythons, strongly support this; the boa's anal spurs and trace remnants of hips and limbs, for instance.
"Snakes are indeed a fragile specimen when it comes to preserving their skeletons. "
He was once an itty bitty glob of clay
GUMBY!
You should see what Gumby can do today
GUMBY!
If you have a heart then Gumby's a part of you
Of you......
GUMBY!
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