Geological Origin of Life

Hello all,This is continuing from another topic started by mike the wiz - (creation argument) - where we were talking about the origin of RNA and DNA based life. Here's what I found:"The first hypothesis about the origin of life was put forward by a Russian scientist named Oparin in 1924 - it stated that the early atmosphere of the Earth was anoxic and consisted of carbon dioxide, methane, ammonia, hydrogen sulphide, etc. When these gases condensed into a "primordial soup" ocean, certain aminoacids could be synthesised if a source of energy was added.Stanley Miller (an American scientist) attempted to reproduce this effect by electrifying the gas mixture, and succeeded in producing several characteristic aminoacids.Another American scientist at the University of Florida named Fox ran more elaborate versions of this experiment, and succeeded in producing protenoids - complex molecules of around 200 aminoacids. As he continued working with them, he showed that over longer periods of time they spontaneously formed into microspheres - bounding membranes required for cells.The most important step was still to discover how primitive life replicated, as all modern life requires DNA and RNA.Recent research suggests that small strands of RNA can replicate without the need for enzymes, unlike DNA - so the early world could have been dominated by RNA organisms.An alternative view is that life did not originate on Earth. The Murchison Meteorite, discovered in Australia in 1969, was classified as a stony meteorite with carbonaceous chondrites - meaning that aminoacids were present. These were different from Earth aminoacids in that they had equal amounts of left and right hand structural configurations in their molecules. Their carbon13 ratio was also much higher - all powerful evidence of their extraterrestrial origin.This lead to the proposition of Hoyle in the 1970's of the panspermia hypothesis - that microbes present in cosmic dust came to settle in the Earth's stratosphere and lead to the development of life.Scientists do agree that life probably did originate in the oceans. Evidence for this is the existence of 'black smokers' - undersea volcanic vents where life thrives without the need for oxygen or sunlight (autotroph bacteria - survive by chemosynthesis)."This is taken more or less verbatim from my own notes - I left out some of the more technical stuff. This is the current view among geologists (the Irish and British ones anyway) about the origin of life.Thoughts anyone?The Rock Hound

I can't believe I haven't got any replies to this yet. This is probably the most controversial subject I can concieve of - some of it even sounds ridiculous to me - and no one wants to talk about it?Do I have to double-dare people or something? The Rock Hound

Well that's that then on to other topics. Wish I'd caught the debate about black smokers though...Incidently Brad I couldn't understand a word of your post - was it supposed to go on a different thread?The Rock Hound

I still can't understand how this relates to my original post. Maybe biochemistry just isn't my strong point... Please explain what you're trying to say in the simplest way possible.The Rock Hound

I actually understood that. Wow.I don't think the panspermia hypothesis really holds any water - it simply brings up the question of how life originated in space, which is far more hostile than Earth. It is generally agreed that life as we know it did originate in the oceans - to me it suggests that there was no other reason except that the oceans were probably less hostile than the land at that time.

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I think of Fox's microspheres as ONLY protein and not pre-existng living protein material of what was the first cytoplasm.

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Remember Fox could not conduct his experiment over the kind of geological timescales we see in the fossil record. It is possible that if the experiment was conducted over millions of years, the first pre-RNA life could eventually occur. If this is the case then the origin of life will never be conclusively proven.The Rock Hound

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I am really thinking it possible to get some notion of INTEGRABLE time in biochange but I wont put a spandrelized token on this subway untill I read somewhere that deductive biogeography actually has a faculty of thought and not and Island of gilligan's Aleph. Jess-I almost did the Clinton thing. We used to Get coal from Clinton NJ but we had to go thru whitehouse not Sommervile to not get i'mcloned in the process.

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Um, you've lost me again. What the hell does spandrelized mean?

Sure - post some of Gould's stuff if you want. In college we only really touched on his work, and I'd like to find out a bit more.The Rock Hound