Shaped from clay [origin of life]

Nature Magazine ^ | 03 November 2005 | Philip Ball

[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.

[PatrickHenry]

Everyone be nice.

[PatrickHenry]

EvolutionPing

A pro-evolution science list with over 310 names. See the list's explanation at my freeper homepage. Then FReepmail to be added or dropped. See what's new in The List-O-Links.

[js1138]

A Blast from the past

Life as we know it is too complex to have originated in its present form. Nucleic acids and proteins and most organic molecules necessary for life are too complex to have originated in the primitive atmosphere even if the conditions were favorable.

We need to find something that is capable of growing, replicating (not perfectly), and providing a substrate for the formation of molecules necessary for life as we know it today. What could possibly do that?

Ah yes, crystals of clay! Clay is abundant. It grows and replicates but not perfectly thus allowing for irregularities to accumulate. These crystals with irregularities could then provide a surface that brought molecules together in close proximity so that they could interact and produce the organic molecules needed for life. Eventually, the secondary organisms that resulted from this process achieved a certain complexity that gave rise to life as we know it.

[Pharmboy]

A bit of history of spontaneous generation.


The Slow Death of Spontaneous Generation (1668-1859)
Russell Levine and Chris Evers

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From the time of the ancient Romans, through the Middle Ages, and until the late nineteenth century, it was generally accepted that some life forms arose spontaneously from non-living matter. Such "spontaneous generation" appeared to occur primarily in decaying matter. For example, a seventeenth century recipe for the spontaneous production of mice required placing sweaty underwear and husks of wheat in an open-mouthed jar, then waiting for about 21 days, during which time it was alleged that the sweat from the underwear would penetrate the husks of wheat, changing them into mice. Although such a concept may seem laughable today, it is consistent with the other widely held cultural and religious beliefs of the time.

The first serious attack on the idea of spontaneous generation was made in 1668 by Francesco Redi, an Italian physician and poet. At that time, it was widely held that maggots arose spontaneously in rotting meat. Redi believed that maggots developed from eggs laid by flies. To test his hypothesis, he set out meat in a variety of flasks, some open to the air, some sealed completely, and others covered with gauze. As he had expected, maggots appeared only in the open flasks in which the flies could reach the meat and lay their eggs.

This was one of the first examples of an experiment in the modern sense, in which controls are used. In spite of his well-executed experiment, the belief in spontaneous generation remained strong, and even Redi continued to believe it occurred under some circumstances. The invention of the microscope only served to enhance this belief. Microscopy revealed a whole new world of organisms that appeared to arise spontaneously. It was quickly learned that to create "animalcules," as the organisms were called, you needed only to place hay in water and wait a few days before examining your new creations under the microscope.

The debate over spontaneous generation continued for centuries. In 1745, John Needham, an English clergyman, proposed what he considered the definitive experiment. Everyone knew that boiling killed microorganisms, so he proposed to test whether or not microorganisms appeared spontaneously after boiling. He boiled chicken broth, put it into a flask, sealed it, and waited - sure enough, microorganisms grew. Needham claimed victory for spontaneous generation.

An Italian priest, Lazzaro Spallanzani, was not convinced, and he suggested that perhaps the microorganisms had entered the broth from the air after the broth was boiled, but before it was sealed. To test his theory, he modified Needham's experiment - he placed the chicken broth in a flask, sealed the flask, drew off the air to create a partial vacuum, then boiled the broth. No microorganisms grew. Proponents of spontaneous generation argued that Spallanzani had only proven that spontaneous generation could not occur without air.

The theory of spontaneous generation was finally laid to rest in 1859 by the young French chemist, Louis Pasteur. The French Academy of Sciences sponsored a contest for the best experiment either proving or disproving spontaneous generation. Pasteur's winning experiment was a variation of the methods of Needham and Spallanzani. He boiled meat broth in a flask, heated the neck of the flask in a flame until it became pliable, and bent it into the shape of an S. Air could enter the flask, but airborne microorganisms could not - they would settle by gravity in the neck. As Pasteur had expected, no microorganisms grew. When Pasteur tilted the flask so that the broth reached the lowest point in the neck, where any airborne particles would have settled, the broth rapidly became cloudy with life. Pasteur had both refuted the theory of spontaneous generation and convincingly demonstrated that microorganisms are everywhere - even in the air.

[mikeus_maximus]

Unbelievable. Simple carbon compounds are combined in the right soil conditions, and from that we're to assume that they not only organized themselves into vastly complex patterns of codified information, but spontaneously generated life. I wish I could have that of faith.

[ASA Vet]

Everyone be nice.

You're asking to much. The SN's will be in full attack mode on this one.
I'll leave before it starts. Thanks for another interesting article.

[RoadTest]

"And God said, Let the waters bring forth abundantly the moving creature that hath life, and fowl that may fly above the earth in the open firmament of heaven. And God created great whales, and every living creature that moveth, which the waters brought forth abundantly, after their kind, and every winged fowl after his kind: and God saw that it was good. And God blessed them, saying, Be fruitful, and multiply, and fill the waters in the seas, and let fowl multiply in the earth. And the evening and the morning were the fifth day." Gen. 1:20

[Calpernia]

[js1138]

Adding to the confusion...

http://originoflife.net/cairns_smith/index.html

[js1138]

I'm wondering why you posted irrelevant spam on this thread.

[Quark2005]

A bit of history of spontaneous generation.

Uh, okay. What maggots spontaneously arising out of rotting meat has to do with this article is quite honestly beyond me.

[Pharmboy]

Well, OK, happy to tell you. First, from an historical point of view re science, I thought it might be interesting to look back at the first wave of spontaneous generation "theories" in terms of how it was thought about. Getting inert molecules to reproduce and thus lay the groundwork for more complex life forms is the modern version...obviously much more sophisticated.

Second, as the article states, some of the first controlled experiments (Spallanzani) were performed to disprove this "theory"--an important milestone in the history of science.

Have a great weekend...

[Quark2005]

I wish I could have that of faith.

No one is asking anyone to have "faith" here. The article demonstrates that certain organic compounds (basic building blocks of life) can arise spontaneously under the right circumstances. There's several links still missing to make a complete picture of abiogenesis, scientists will readily admit that. Abiogenesis is not as complete a theory as biological evolution, which has been proven beyond a shadow of a doubt. However, there are a lot of pieces of the picture that have come together.

This doesn't mean we should stop looking for reasons, though. That is what science is all about.

[Pharmboy]

See number 12 above.

[Eric in the Ozarks]

Its called Kitty Litter.

[MineralMan]

"Unbelievable. Simple carbon compounds are combined in the right soil conditions, and from that we're to assume that they not only organized themselves into vastly complex patterns of codified information, but spontaneously generated life. I wish I could have that of faith."

---

Wow! There's an amazing misreading of an article, if I ever saw one.

You might want to try reading it through one more time. You seem to have missed the salient facts in it.

[Quark2005]

Getting inert molecules to reproduce and thus lay the groundwork for more complex life forms is the modern version...obviously much more sophisticated.

The last part of your sentence here being the key parrt. No one is suggesting that complex life forms arose suddenly from nothing. Here we have a testable theory of how certain organic molecules arose. This has nothing to do antiquated spontaneous generation concepts.

What suggestion would you make for the scientific research of the origins of life on earth, if you do not find this research to be adequate?

[VadeRetro]

Note to the dumb-as-a-stump crowd:

THIS IS RESEARCH INTO "ABIOGENESIS." YES, IT IS SPECULATIVE. HOWEVER, IT IS NOT DIRECTLY RELATED TO WHETHER THE CURRENT LIFE FORMS OF EARTH ARE RELATED BY COMMON DESCENT. THE MECHANISMS INVESTIGATED HERE ARE NOT "HERITABLE RANDOM VARIATION AND NATURAL SELECTION," THE CLASSICAL ENGINE OF DARWINIAN EVOLUTION.

[Doctor Stochastic]

Clays are a good candidate. I don't suppose there's much naturally occuring Raney Nickel lying around.

[Pharmboy]

Look...you're reading me completely wrong. I am someone who is very interested in the history of science. I am also a Darwinist, and have been such my whole life. There are plenty of creationists around for you to fight with, so go get 'em. And, in the future, I will be very careful about linking modern scientific events to those in history...point taken. And, you might want to switch to decaf.