urey-miller importance...

[mcoy]

I've been reading through some articles on the web, about the urey-miller experiment.. i read that the model is currently being replaced by some other theory that life began underwater... (its all on the internet...)

so, if urey-miller has been rejected as a valid theory for life origin, does it still have any importance at all?

[swansont]

Yes. There are some who claim that abiogenesis is impossible because the odds of the cells forming are a bazillion-to-one. The Miller-Urey experiment rebuts the notion that the outcomes of chemistry are all equally probable, which is but one of the fallacies/misconceptions that go into that particular argument.

[Deathby]

I thought the point of Urey Miller was to say that life began underwater. Cause the setup was lightning strikes the clouds, carbon compounds are formed which collect in the little bottle of water down the bottom representing the ocean.

 

So life formed underwater (even according to the Urey Miller experiments).

If you mean deep underwater in sulfur vents, I think there was a similar experiment which showed organic chemicals could occur that way too. And another which said they could form in asteroids even at space temperatures from (I think) UV rays.

[mcoy]

I thought the point of Urey Miller was to say that life began underwater. Cause the setup was lightning strikes the clouds' date=' carbon compounds are formed which collect in the little bottle of water down the bottom representing the ocean.

 

So life formed underwater (even according to the Urey Miller experiments).

If you mean deep underwater in sulfur vents, I think there was a similar experiment which showed organic chemicals could occur that way too. And another which said they could form in asteroids even at space temperatures from (I think) UV rays.[/quote']

 

actually the urey miller experiment suggests that the eath conditions on the earth, which was reduced (+O). so it couldnt be just water althought water was definitely there... but scientists has deduced that the earth couldnt possibly have that kind of environment since the earth's tectonic movement is very violent at those times. the underwater theory however is different (by a german scientist). have a search in this forum's database bou d experiment or primordial soup.

[yialanliu]

Yes, they are rejected because there are jsut way too many flaws in that experiment.

As of now, I haven't read aobut any major discoveries and am still waiting

[Skye]

but scientists has deduced that the earth couldnt possibly have that kind of environment since the earth's tectonic movement is very violent at those times.

Some have recently argued that the early atmosphere may have had a fair amount of hydrogen though:

 

http://newsrelease.uwaterloo.ca/news.php?id=4348

[mcoy]

well there still lots of other flaws that invalidates the theory... most importantly the impossibility of amino acids to be synthesized into protein, which is needed to make dna.. however i've read in some boook that rna can be formed by itself??(sombeody correct me please if you know the theory...) but i dont see how rna can help synthesize protein or dna. chances are comparable to impossible for it to happen.

 

As of now, I haven't read aobut any major discoveries and am still waiting

 

well as i've said theres a new hteory that life began underwater... by some german scientist. i didnt really look much into it tho. but i think they're working on it.

[Mokele]

however i've read in some boook that rna can be formed by itself??(sombeody correct me please if you know the theory...)

 

Correct, and it has in numerous laboratory experiments. Also, RNA can fold an act as a catalyst, similar to a protien (but less efficient). Current theory is that the first steps towards life were self-replicating RNA catalysts. Indeed, it's entirely possible that the first organisms could have been based wholy off RNA, with the RNA fulfilling the role of both genetic material and biological catalyst.

 

but i dont see how rna can help synthesize protein or dna. chances are comparable to impossible for it to happen.

 

I'd love to hear how you concluded that. Just because we don't know precisely how it happened doesn't mean that it couldn't or was "comparable to impossible". That's like saying that just because we don't know how galaxies formed, their formation was next to impossible.

 

Mokele

[swansont]

well there still lots of other flaws that invalidates the theory... most importantly the impossibility of amino acids to be synthesized into protein, which is needed to make dna.

 

Where and when was this proven to be impossible?

[mcoy]

sorury, my bad. what i meant was the probability is almost impossible.

[swansont]

sorury, my bad. what i meant was the probability is almost impossible.

 

 

But that was my earlier point. The probability of forming amino acids was calculated to be very small, and the Miller-Urey experiment shows that such calculations are flawed. So the calculations showing the formation of proteins to be vanishingly small is also likely flawed. The outcomes of chemistry are not random - not all combinations of elements are equally probable.

[Bluenoise]

but i dont see how rna can help synthesize protein or dna. chances are comparable to impossible for it to happen.

 

Uhhh RNA does help synthesize proteins and DNA. There are many important RNA components to both DNA polymerase and Ribosomes. Actually the main catalytic component of Ribosomes is RNA... So I don't know where you're getting this comparable to impossible trash from since we know it to happen.

[mcoy]

so you mean that if theres an existing single rna it means that protein is defintely going to be synthesized? wow, such trash it is.

[Mokele]

No, that's not what they mean. Swansont was basically simply saying that chances of polypeptides forming from a pool of amino acids is much better than random chance alone indicates, because the molecules are interacting according to set, non-random laws. Bluenoise was pointing out that RNA continues to have catalytic properties of majors importances in cells, namely in ribosomes.

 

Plus, there's the sheer scale. A mole of monomer precursors for all of these could be disolved in a modest quantity of water, maybe as little as 1 liter. Now, I've forgotten just how many atoms are in a mole, but it's Huge, something like 10^23 atoms. Now, multiple that by how many liters of water are in the ancient ocean.

 

The chances of a single lottery ticket winning are infinitesimally tiny, but when you have 100 trillion tickets, you're pretty much guaranteed a win.

 

Mokele

 

Mokele

[mcoy]

No, that's not what they mean. Swansont was basically simply saying that chances of polypeptides forming from a pool of amino acids is much better than random chance alone indicates, because the molecules are interacting according to set, non-random laws. Bluenoise was pointing out that RNA continues to have catalytic properties of majors importances in cells, namely in ribosomes.

 

understood...

 

Plus' date=' there's the sheer scale. A mole of monomer precursors for all of these could be disolved in a modest quantity of water, maybe as little as 1 liter. Now, I've forgotten just how many atoms are in a mole, but it's Huge, something like 10^23 atoms. Now, multiple that by how many liters of water are in the ancient ocean.

 

The chances of a single lottery ticket winning are infinitesimally tiny, but when you have 100 trillion tickets, you're pretty much guaranteed a win.

[/quote']

--we need to consider some more facts as well, here's some site to help...

DARWINISM REFUTED: MOLECULAR BIOLOGY....

This is from the site...

The likelihood of the spontaneous formation of life from inanimate matter is one to a number with 40,000 noughts after it... It is big enough to bury Darwin and the whole theory of evolution. There was no primeval soup, neither on this planet nor on any other, and if the beginnings of life were not random, they must therefore have been the product of purposeful intelligence

If we add together the three probabilities (that of amino acids being laid out correctly, that of their all being left-handed, and that of their all being joined by peptide links), then we come face to face with the astronomical figure of 1 in 10950. This is a probability only on paper. Practically speaking, there is zero chance of its actually happening. As we saw earlier, in mathematics, a probability smaller than 1 in 1050 is statistically considered to have a "zero" probability of occurring.

[Skye]

That site shows that it's improbable for a modern living systems to spontaneously form. I don't think any scheme for the formation of life involves life spontaneously forming in a modern state though, so it's a moot point.

[swansont]

--we need to consider some more facts as well' date=' here's some site to help...

DARWINISM REFUTED: MOLECULAR BIOLOGY....

 

"The likelihood of the spontaneous formation of life from inanimate matter is one to a number with 40,000 noughts after it...

 

If we add together the three probabilities (that of amino acids being laid out correctly, that of their all being left-handed, and that of their all being joined by peptide links), then we come face to face with the astronomical figure of 1 in 10950. This is a probability only on paper. Practically speaking, there is zero chance of its actually happening. As we saw earlier, in mathematics, a probability smaller than 1 in 1050 is statistically considered to have a "zero" probability of occurring."

 

Uh, facts. Riiiight.

 

This is exactly to what I was referring. The probability calculations are spectacularly wrong, and the Miller-Urey experiment is a demonstration of this. Some of those purported 40,000 zeroes go into the probability of formation of the amino acids. But wait, they shouldn't be there, since that probability is basically 1! And many of the other "random result" probabilities are done wrong, too. The outcomes of chemistry are not random.

 

Not to mention that you can't prove something is impossible with probabilities if, in fact, the event has occurred. And that predicting some result is different than predicting a specific result. You being born, as you, is a huge improbability: your dad had to meet your mom, they had to fall in love, they had to have sex at just the right time for that sperm to meet up with that egg, the chromosomes had to recombine in just the right way, etc. for you to be who you are. And multiply that all the way back to Noah and his family (if you believe in that sort of thing), because your grandparents had to meet and have all that happen for your parents to be born. And so on, and so on, all the way back.

 

The odds of you specifically, being alive are astronomical, using that reasoning. And yet you are alive. Which only goes to confirm GIGO (garbage in, garbage out).

[Bluenoise]

The basic current idea is that RNA was the original molecule of life (If you'd call that life). RNA forms readily from the compounds that we believe to have been present on the premordial Earth. This RNA can spontanously assemble into polynucleotide chains.

Now since different chains can have different properties that they excert on molecules around them it is believe that eventually chains formed that were able to increase the probability of similar chains forming. Many refer to this phenomen as the principle of self-organisation. This is where natural selection comes in, If a specific chain can have some positive effect on the probability of it occuring again then it has positive selection on it's side. Even if these probabilites just shift the slightest bit, the shift is likely to increase by more the next time around since you'll have slightly more similar molecules complimenting each others formation, though you will be depleting the resources.

As I stated earlier we know RNA to have catalytic ability (i.e a Ribozyme), so if you had a Ribozyme that has the capacity to copy strands of RNA, they it may copy itself, and self propagate. This definatley not a stretch since RNA has a large part in Replicating DNA, and is know to replicate on it's own template. Eventually over time such a sea of Self propagating RNA's would start to deplete free nucleotides, so having an Ribozyme present that can produce Molecules that can utilies other compounds to recreate more RNA or contain it would be beneficial (i.e. proteins (as well has having thousands of other uses)). And there are Ribozymes like this. They're the main catalytic component of Ribosomes. DNA formation would be probably now since you have the molecules present that we know are needed to assemble and accuratley copy DNA. Using DNA as the template for life is much better then using RNA since it is much more stable, so it's believed that DNA replaced RNA as the template for life.

Now other steps would be things like formation of a membrane to contain the system, phospholipids do self assemple into phospholipid bilayers, so the system would just need to be able to guide them around itself then later guide their formation. Then compartmentalisation to create organelles so different parts of cells can have different functions that would otherwise conflict in the same space. This is also the idea with the formation of multicelluar life. Different cells for different fuctions, the ability to take more stress and survive. Formation into tissues, organs, and body plans can all be seen to logically follow.

 

Note: Please people I just threw this all out off the top of my head so be gentle. And I'm definatley not saying that this was the exact order of things, most likely some or most of these things developed side by side from steps that we will never guess, but I think it's a fair outline of the basic idea.

 

Now notice how every progressive step in a theory like this increase the probability of this system of molecules propagating itself? So in effect it is the next probable step. Since any negative step would produce somethign that would be overwhelmed and lost by the more probable ones. Darwinian natural selection in effect. The problem mcoy with the resources that you're quoting is that they're attempting to refute a theory that no one believes anyways. They don't take the time to study the actual view on something and just assume that it's something else like that a complex organism will just spontanously self assemble. No ones saying that. The current argument is once of many small steps.

If you take life to spontaneously form a complex organism in a slipt second the probability is nilch. But if you let it take a small step every 1000's of years or so and strech that out over 4 billion years it almost seems unavoidable.

[Mokele]

--we need to consider some more facts as well, here's some site to help...

DARWINISM REFUTED: MOLECULAR BIOLOGY....

 

The others have effectively handled this in my absence, but I'd like to point out that the site can simply and easily be dismissed without even reading it. Why? Because it confuses abiogenesis with evolution, including Darwin's original formulation of evolution. This indicates that a) it's the product of someone with an axe to grind with evolution trying to bolster their agenda and, more importantly, b) that the writers of the site are barely even scientificly literate if they consider the two to be a single connected theory.

 

Frankly, the title alone reeks enough of creationist garbage that the above refutations are simply icing on the cake.

 

Mokele