Primitive life on Earth

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Primitive life on Earth

Postby Chris Sergeant » Fri Oct 28, 2011 12:43 pm

Mud volcanoes at Isua, in south-west Greenland, have been identified as a possible birthplace for life on Earth. . . Almost four billion years ago, these volcanoes released chemical elements indispensable to the formation of the first biomolecules, under conditions favorable to life. . .
Focused their studies on serpentinites from Isua, in south-west Greenland, which date from the start of the Archean. . . Using isotopes of zinc as indicators of the basic or acid nature of an environment, the researchers highlighted the basic character of the thermal fluids that permeated the Isua serpentinites, thus demonstrating that these minerals formed a favorable environment for amino-acid stabilization.
Nearly four billion years ago, at a time when the continents only occupied a very small part of the surface area of the globe, the oceanic crust of Isua was permeated by basic hydrothermal fluids, rich in carbonates, and at temperatures ranging from 100 to 300°C. Phosphorus, another indispensable element to life, is abundant in environments where serpentinization takes place. As this process generates mud volcanoes, all the necessary conditions were gathered at Isua for organic molecules to form and be stable. The mud volcanoes at Isua thus represent a particularly favorable setting for the emergence of primitive terrestrial life.

http://www.sciencedaily.com/releases/20 ... 090340.htm

The Isua Supracrustal Belt (3.8 billion years old) shows evidence of active plate tectonics. The Isua deposits also contain fossilized evidence of early bacterial life on Earth. The features and the chemistry of ophiolites indicate that the area was formed as the result of seafloor spreading.
http://www.sciencedaily.com/releases/20 ... 191123.htm
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Re: Primitive life on Earth

Postby a_haworthroberts » Sat Oct 29, 2011 2:25 am

This link suggested continental drift and so on started around 3 bn years' ago. But I imagine it could have been earlier still.

http://www.sciencedaily.com/releases/20 ... 142402.htm
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Re: Primitive life on Earth

Postby Luke Tyler » Tue Nov 29, 2011 10:16 pm

This is one aspect I'm exremely uncertain about. I don't understand how entirely random, unguided, violent and destructive forces without direction are supposed to achieve something that we as intelligent, precise beings with highly specialised machinery cannot. I don't see how life could be created randomly by processes far more likely to render life impossible, when life is something which we as scientists are unable to replicate.
If anyone could help me out here, I'd be very thankful. And please don't give me the yarn about Kenneth Miller's experiments, I can't see how that is of any relevance.
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Re: Primitive life on Earth

Postby jon_12091 » Tue Nov 29, 2011 11:00 pm

Uncertainty is the key word. There is long list of things we are to varying degrees uncertain of when it comes to conditions on the early Earth. We are also uncertain of the precise mechanism(s) by which chemicals compounds became increasingly complex to the point they could self replicate (and in fact I think its fair to say we will never be certain even if we manage it in the lab or observe it in action on another planet). The shear number of ideas can judged from the following article
http://en.wikipedia.org/wiki/Abiogenesis
However, the Earth system is not random, though violent and destructive in parts, which produce interesting chemical conditions. Whether or not the Earth system is guided or otherwise is a philosophical argument. I would describe it as 'unguided', but in the sense that God produced a 'good creation' that doesn't need constant miraculous propping up. Some atheists parody God, playing on the stereotype of an elderly bearded WASP of a God sitting on cloud, the magic sky fairy, unfortunately a lot of creationists seem to pander to that stereotype because they are unable to contemplate the complexity of creation and therefore unable to comprehend it could function without constant divine intervention.
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Re: Primitive life on Earth

Postby Dagsannr » Tue Nov 29, 2011 11:15 pm

Luke Tyler wrote:This is one aspect I'm exremely uncertain about. I don't understand how entirely random, unguided, violent and destructive forces without direction are supposed to achieve something that we as intelligent, precise beings with highly specialised machinery cannot. I don't see how life could be created randomly by processes far more likely to render life impossible, when life is something which we as scientists are unable to replicate.
If anyone could help me out here, I'd be very thankful. And please don't give me the yarn about Kenneth Miller's experiments, I can't see how that is of any relevance.


You also need to consider that evolution (and in a sense the original abiogeneis) is not random. Unguided, yes, but not random. The driving factors behind evolution are well understood and whilst some mutations occur randomly (not all of them), most the changes that occur in organisms are in response to a changing environment; factors that are easily explained and follow predictable pathways.

The conditions thought to exist on a primeval Earth - low oxygen levels, high carbon dioxide, hot, wet, full of volatile organic compounds, stormy, are almost ideal for the creation of highly complex, self-replicating polymers. Add into that factor that the conditions are a blank slate (nothing to compete with), once those first molecules form, there's nothing to stop them growing ever more complex. The generation of precursor molecules to amino acids is guaranteed under those conditions. Organic chemistry follows very well defined rules and, unlike a lot of chemistry, actually likes bigger, more complex molecules. Carbon really, really wants to bond to lots of different things, and once you get a lot together, they all share electrons and are even more stable. That we havn't managed to synthesis it yet is more telling of our inability to accurately protray those early conditions that any other factor.

Plus, remember one thing - the Earth had hundreds of millions of years and tens of thousands of square miles to react with. No scientist is going to get the funding to replicate that kind of experiment!

The fact that wherever we look in the universe we see alcohol, ammonia, water and methane (the building blocks of life as we know it) is testament to the possibility that life, if given a slate upon which to react (like a rocky planet with a hot atmosphere, or an asteroid with plenty of solar radiation) is almost inevitable.
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Re: Primitive life on Earth

Postby Michael » Wed Nov 30, 2011 7:41 am

Luke

Try reading things by Simon Conway Morris.

He is an Anglican Christian too!!!!!
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Re: Primitive life on Earth

Postby Luke Tyler » Wed Nov 30, 2011 9:01 pm

Natman wrote:The fact that wherever we look in the universe we see alcohol, ammonia, water and methane (the building blocks of life as we know it) is testament to the possibility that life, if given a slate upon which to react (like a rocky planet with a hot atmosphere, or an asteroid with plenty of solar radiation) is almost inevitable.


I'm not sure. It seems very unlikely that these substances would all be around in an area of intense pressure and some kind of solar radiation would fuse them all together. I just don't think that something like this could occur when we are unable to recreate the same effects in a laboratory. I appreciate that we don't have millions of square miles, but we can replicate temperature, pressure and have all the substances present.
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Re: Primitive life on Earth

Postby Dagsannr » Wed Nov 30, 2011 9:27 pm

Luke Tyler wrote:I'm not sure. It seems very unlikely that these substances would all be around in an area of intense pressure and some kind of solar radiation would fuse them all together. I just don't think that something like this could occur when we are unable to recreate the same effects in a laboratory. I appreciate that we don't have millions of square miles, but we can replicate temperature, pressure and have all the substances present.


You don't need high temperatures and pressures to synthesise long-chain organic molecules - most of them are quite happy to react at relatively low pressures and temperature in space can fluctuate a lot, in direct sunlight, temperatures on exposed surfaces can easily hit a couple of hundred Kelvin.

Don't take my word for it, in 2009, NASA detected glycine, an amino acid, in asteroid ejecta - http://stardust.jpl.nasa.gov/news/news115.html

An alternatice theory of abiogenesis is the formation of complex molecules and primitive cells around hydrothermal vents. High temperatures, incrediblely high pressures, all the necessary chemicals; what more would a proto-organism need?
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Re: Primitive life on Earth

Postby Luke Tyler » Wed Nov 30, 2011 9:41 pm

Natman wrote:
An alternatice theory of abiogenesis is the formation of complex molecules and primitive cells around hydrothermal vents. High temperatures, incrediblely high pressures, all the necessary chemicals; what more would a proto-organism need?


Wouldn't the high temperatures and pressures destroy the new organism as soon as it was formed?
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Re: Primitive life on Earth

Postby jon_12091 » Wed Nov 30, 2011 10:26 pm

Luke Tyler wrote:
Natman wrote:
An alternatice theory of abiogenesis is the formation of complex molecules and primitive cells around hydrothermal vents. High temperatures, incrediblely high pressures, all the necessary chemicals; what more would a proto-organism need?


Wouldn't the high temperatures and pressures destroy the new organism as soon as it was formed?


Bacteria survive quite happily in the subsurface of the Earth at up to 15000 feet (no idea what pressure, but it will be significant) and temperatures up 150^oC - and that includes Archea which are some of the oldest. I've also watched the little subsurface buggers reproduce after being irradiated with a couple of thousand Grays.
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Re: Primitive life on Earth

Postby psiloiordinary » Wed Nov 30, 2011 10:39 pm

hi Luke,

You said;


I'm not sure. It seems very unlikely that these substances would all be around in an area of intense pressure and some kind of solar radiation would fuse them all together. I just don't think that something like this could occur when we are unable to recreate the same effects in a laboratory. I appreciate that we don't have millions of square miles, but we can replicate temperature, pressure and have all the substances present.


Take a pack of cards and deal them out one at a time making a note of the order you got.

Now shuffle them again.

Now deal them out again in your lab one at a time and let me know when you get the same exact order you had before.

If you don't get the right order keep trying and after a while then surely according to your comment above you have just proven that your first deal must have been done by god and not you - ??
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Re: Primitive life on Earth

Postby Dagsannr » Wed Nov 30, 2011 11:24 pm

psiloiordinary wrote:Take a pack of cards and deal them out one at a time making a note of the order you got.

Now shuffle them again.

Now deal them out again in your lab one at a time and let me know when you get the same exact order you had before.

If you don't get the right order keep trying and after a while then surely according to your comment above you have just proven that your first deal must have been done by god and not you - ??


That reminds me of a quote, I can't remember who it was by - someone like Tim Minchin or Ben Goldacre:

"I was on my way home today and I saw a car with the registration number PY10 CZF. What were the chances of that?!"

Plus, Luke, don't fall into the incredulity trap - just because you don't understand the science behind something, doesn't diminish its likelihood. If you can accept that biochemists are confident that the conditions to create complex organic molecules existed, and such chemicals could be created, then go with it. The world is too complex to know and understand everything at once. Concentrate on one field and trust the experts in the others.
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Re: Primitive life on Earth

Postby Dr_GS_Hurd » Thu Dec 01, 2011 3:01 am

Luke Tyler wrote:This is one aspect I'm exremely uncertain about. I don't understand how entirely random, unguided, violent and destructive forces without direction are supposed to achieve something that we as intelligent, precise beings with highly specialised machinery cannot. I don't see how life could be created randomly by processes far more likely to render life impossible, when life is something which we as scientists are unable to replicate.
If anyone could help me out here, I'd be very thankful. And please don't give me the yarn about Kenneth Miller's experiments, I can't see how that is of any relevance.


Take a look at A Short Outline of the Origin of Life.

And, why should we want to "replicate" life. We can profit much more merely manipulating, or "customizing" life as we find it today. We are resurrecting ancient, primitive genes for both basic science, and some new approaches to building better antibiotics.

PS: " we as scientists "??? You are a scientist?
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Re: Primitive life on Earth

Postby cathy » Thu Dec 01, 2011 11:20 am

Wouldn't the high temperatures and pressures destroy the new organism as soon as it was formed?

Firstyl extremophiles do exist, so life exists at the extremes, and we're not looking at organisms as you understand it, we're looking at things that have some of the features of life. Secondly there are also plenty of minerals around these hydrothermal vents that seem to offer some protection. Thirdly that is not the only hypothesis being tested at the moment. There is an interesting one at Glasgow university trying to look at the role of organometallic compounds, there is the number of organic compounds including amino acids found on meteorites like the Murchinsons meteorite and lots more about what is going on at the hydrothermal vents under different conditions. Fifthly organic chemistry may be nice at A level (tho you'll be doing it to death in unit 4 next year) but Natman is right, at university you'll realise just how complicated it can be all by itself. Just vary the conditions and see what you get. You'll either love it or more likely hate it. Then there is the debate of whether metabolism or replication came first and then there is the slow process of piecing together a very complex jigsaw. But that is science, the day we know everything science will cease to exist.

The problem is not that nobody can answer the question here it is that there is too much research going on at the moment to know it all in detail. And that not only includes the research that gets to one or other of the features of life but also research as to how they gradually come together. But a lot of that research is fruitful and is giving clues to tiny parts of that jigsaw.

I suggest you start by typing abiogenesis into wikkipeadia and move on from there to gether more detail (it is ok on this if possibly a bit simplified). I assume as part of your sixth form life they'll be encouraging you to read around your subjects to help with uni interviews if nothing else. My daughter has often found things in New Scientist on the latest abiogenesis stuff that has led her to look further. You don't need to delve to far. In last weeks there was an interesting article about LUCA and how it may have swopped traits rather than competed.

Lastly don't buy into the creationists unguided and random line. Life may be unguided but natural selection is very powerful and that makes life far from random. And early life would not be that subject to too much competition and could just evolve to suit the environment and changes in it. Something that occurs easily with very simple things.

And lastly again, we know it happened because we the evidence is all around us, we are here. Even if we don't find out how in the foreseeable future, all the best evidence states earliest life was simple photosynthesising cells not all kinds. Our universe seems to have began with conditions that allowed the laws of physics to give rise to stars that gave rise to chemistry, chemistry that gives rise to biology etc. It would be a very odd God that messed up at the chemistry stage and had to come down and specifically make DNA as many creationists claim. It would suggest an huge error. And Psi and Tim Minchin are spot on about probability, life is only improbable if you start with the notion it has to conclude with DNA and us. So the DNA contains info, so needs a designer argument is nonsense.

Natmans right we don't know everything yet. From what you are saying I'm guessing you're hearing a fair bit of the origin of life is impossible line and the how do we get something as complex as DNA without a designer, information rubbish that our Marc and Andy McIntosh amongst others are so keen on. They are squeezing God into gaps in knowledge. Creationists and IDers have done that before with things like the bacterial flagellum. If your only evidence for God comes from gaps in knowledge then beware, those gaps eventually get filled in.

Marc has said his faith will disappear when we find ways for life to develop. He may or may not be lucky enough to remain a Christian in his lifetime. I'd guess not-he's bet far too much of his faith on a book that was proved to be not literal account of how the world is hundreds and hundreds of years before he was born as far as I can see, long before Darwin. then again he's a past master on selective, wilful ignorance so I guess he'll manage somehow. But the Christians here who accept the science are safe whatever way science finds to demonstrate how.
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Re: Primitive life on Earth

Postby cathy » Thu Dec 01, 2011 11:20 am

Wouldn't the high temperatures and pressures destroy the new organism as soon as it was formed?

Firstyl extremophiles do exist, so life exists at the extremes, and we're not looking at organisms as you understand it, we're looking at things that have some of the features of life. Secondly there are also plenty of minerals around these hydrothermal vents that seem to offer some protection. Thirdly that is not the only hypothesis being tested at the moment. There is an interesting one at Glasgow university trying to look at the role of organometallic compounds, there is the number of organic compounds including amino acids found on meteorites like the Murchinsons meteorite and lots more about what is going on at the hydrothermal vents under different conditions. Fifthly organic chemistry may be nice at A level (tho you'll be doing it to death in unit 4 next year) but Natman is right, at university you'll realise just how complicated it can be all by itself. Just vary the conditions and see what you get. You'll either love it or more likely hate it. Then there is the debate of whether metabolism or replication came first and then there is the slow process of piecing together a very complex jigsaw. But that is science, the day we know everything science will cease to exist.

The problem is not that nobody can answer the question here it is that there is too much research going on at the moment to know it all in detail. And that not only includes the research that gets to one or other of the features of life but also research as to how they gradually come together. But a lot of that research is fruitful and is giving clues to tiny parts of that jigsaw.

I suggest you start by typing abiogenesis into wikkipeadia and move on from there to gether more detail (it is ok on this if possibly a bit simplified). I assume as part of your sixth form life they'll be encouraging you to read around your subjects to help with uni interviews if nothing else. My daughter has often found things in New Scientist on the latest abiogenesis stuff that has led her to look further. You don't need to delve to far. In last weeks there was an interesting article about LUCA and how it may have swopped traits rather than competed.

Lastly don't buy into the creationists unguided and random line. Life may be unguided but natural selection is very powerful and that makes life far from random. And early life would not be that subject to too much competition and could just evolve to suit the environment and changes in it. Something that occurs easily with very simple things.

And lastly again, we know it happened because we the evidence is all around us, we are here. Even if we don't find out how in the foreseeable future, all the best evidence states earliest life was simple photosynthesising cells not all kinds. Our universe seems to have began with conditions that allowed the laws of physics to give rise to stars that gave rise to chemistry, chemistry that gives rise to biology etc. It would be a very odd God that messed up at the chemistry stage and had to come down and specifically make DNA as many creationists claim. It would suggest an huge error. And Psi and Tim Minchin are spot on about probability, life is only improbable if you start with the notion it has to conclude with DNA and us. So the DNA contains info, so needs a designer argument is nonsense.

Natmans right we don't know everything yet. From what you are saying I'm guessing you're hearing a fair bit of the origin of life is impossible line and the how do we get something as complex as DNA without a designer, information rubbish that our Marc and Andy McIntosh amongst others are so keen on. They are squeezing God into gaps in knowledge. Creationists and IDers have done that before with things like the bacterial flagellum. If your only evidence for God comes from gaps in knowledge then beware, those gaps eventually get filled in.

Marc has said his faith will disappear when we find ways for life to develop. He may or may not be lucky enough to remain a Christian in his lifetime. I'd guess not-he's bet far too much of his faith on a book that was proved to be not literal account of how the world is hundreds and hundreds of years before he was born as far as I can see, long before Darwin. then again he's a past master on selective, wilful ignorance so I guess he'll manage somehow. But the Christians here who accept the science are safe whatever way science finds to demonstrate how.
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