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Is there any proof that abiogenesis is...

a_drumming_dog
Posts: 93
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11/11/2014 12:44:10 AM
Posted: 2 years ago
Is there any solid proof that abiogenesis is actually possible? I'm a senior in high school right now and my AP Biology explained the Miller - Urey experiment to us and just kind of assumed that it was possible from then on. But to be honest, that didn't really cut it for me. First, the experiment only yielded three kind of amino acids. Life as we know it now need about 20 different ones now if i'm not mistaken. Furthermore, I've come to learn that most life only uses left handed amino acids, and not right handed ones at all. The more I think about it, the less likely it seems. Even the simplest bacteria need enough genes to code for about 1,000 proteins. That pretty complex to just appear. I guess you could consider viruses as the simplest forms of life, but they need cells to reproduce. I don't think they would have been able to arise and continue living then.

http://en.wikipedia.org...

Any thoughts?
The truth will set you free
Burzmali
Posts: 1,310
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11/11/2014 1:22:31 AM
Posted: 2 years ago
I guess the thing to keep in mind is that the Miller-Urey experiment happened over the course of a week. From what we've been able to discover, life seems to have developed around 3 billions years ago. That's more than a billion years after the earth formed. Even if the conditions for life only existed for a million years before when we believe life developed, that's ~365,000,000x longer than the Miller-Urey experiment with a volume of space to occur in that is inconceivably larger than the Miller-Urey environment. Also, in 2008, they discovered that a second experiment had yielded 22 amino acids. This one was intended to simulate the contribution from volcanic activity.

That still doesn't answer your question about whether proof exists. Science doesn't deal in proofs. What we have is evidence that it is possible. That's about as good as we're going to get unless someone conducts another similar experiment and bacteria actually develop in it.
Burzmali
Posts: 1,310
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11/11/2014 1:23:26 AM
Posted: 2 years ago
At 11/11/2014 1:22:31 AM, Burzmali wrote:
I guess the thing to keep in mind is that the Miller-Urey experiment happened over the course of a week. From what we've been able to discover, life seems to have developed around 3 billions years ago. That's more than a billion years after the earth formed. Even if the conditions for life only existed for a million years before when we believe life developed, that's ~365,000,000x longer than the Miller-Urey experiment with a volume of space to occur in that is inconceivably larger than the Miller-Urey environment. Also, in 2008, they discovered that a second experiment had yielded 22 amino acids. This one was intended to simulate the contribution from volcanic activity.

That still doesn't answer your question about whether proof exists. Science doesn't deal in proofs. What we have is evidence that it is possible. That's about as good as we're going to get unless someone conducts another similar experiment and bacteria actually develop in it.

Man, I'm tired. Adjust that ~365,000,000 number to ~52,000,000. Weeks, not days. Dur.
Kaynex
Posts: 5
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11/11/2014 1:36:59 AM
Posted: 2 years ago
The Urey-Miller experiment was not to prove abiogenesis, but instead see what basic building blocks of life could be put together with an early atmosphere. The result was shocking and better than expected. This is why the experiment is remembered.

Now, newer versions of the experiment, with the intention of discovering abiogenic chemicals have taken place. Many ways of making those amino acids have been shown. Just last year in December, the Georgia institute of technology found a way for RNA to self assemble. We have discovered everything necessary to form a primitive cell, the only hard part is getting everything together and forming it.

Abiogenesis is not only possible, but as far as mainstream science is concerned, it's likely correct, and soon to be understood.
Envisage
Posts: 3,646
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11/11/2014 6:39:18 AM
Posted: 2 years ago
At 11/11/2014 12:44:10 AM, a_drumming_dog wrote:
Is there any solid proof that abiogenesis is actually possible? I'm a senior in high school right now and my AP Biology explained the Miller - Urey experiment to us and just kind of assumed that it was possible from then on. But to be honest, that didn't really cut it for me. First, the experiment only yielded three kind of amino acids. Life as we know it now need about 20 different ones now if i'm not mistaken. Furthermore, I've come to learn that most life only uses left handed amino acids, and not right handed ones at all. The more I think about it, the less likely it seems. Even the simplest bacteria need enough genes to code for about 1,000 proteins. That pretty complex to just appear. I guess you could consider viruses as the simplest forms of life, but they need cells to reproduce. I don't think they would have been able to arise and continue living then.

http://en.wikipedia.org...

Any thoughts?

Note that you need to understand that the first life that would have been produced by abiogenesis would have been absolutely nothing like even the simplest of life that is extant today. A very long time has passed between those events and life has evolved to the extent that even if life was being produced via. abiogenesis today it would be rapidly out-competed by existing life in virtually every department.

Abiogenesis would produce a system that:

1. Reproduces
2. Adapts

That's literally about it, the bare minimum requirement for life to begin. If we consider life that is extant today we have systems that:

1. Reproduce
2. Adapt
3. Sense
4. Metabolise
5. Grow
6. Homeostasis

While these additional functions are essential for life today to exist, they would not have been necessary for life to begin in the first place. Hence even if it was the case that the amino acids that we have today aren't the same as were available abiotically, as were the lipids, nucleotides, etc, it really doesn't matter, as they are very easily later adaptions of evolutions once you have a basic self-replicating system that can adapt.

Some models of abiogenesis for example, require just a single encapsulated ryboyme (which isn't even a protein) to kick-start life, etc. Far simpler than the thousands of proteins that bacteria possess today.

Hope this helps.
Otokage
Posts: 2,351
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11/11/2014 9:39:42 AM
Posted: 2 years ago
At 11/11/2014 12:44:10 AM, a_drumming_dog wrote:
Is there any solid proof that abiogenesis is actually possible? I'm a senior in high school right now and my AP Biology explained the Miller - Urey experiment to us and just kind of assumed that it was possible from then on. But to be honest, that didn't really cut it for me. First, the experiment only yielded three kind of amino acids. Life as we know it now need about 20 different ones now if i'm not mistaken. Furthermore, I've come to learn that most life only uses left handed amino acids, and not right handed ones at all. The more I think about it, the less likely it seems. Even the simplest bacteria need enough genes to code for about 1,000 proteins. That pretty complex to just appear. I guess you could consider viruses as the simplest forms of life, but they need cells to reproduce. I don't think they would have been able to arise and continue living then.

http://en.wikipedia.org...

Any thoughts?

You ask if it is possible. Yes, it is possible in the sense that there is no contradictions in the assumptions made, or any physical impossibilities against the process (in the sense that it does not violate the laws of nature). This does not mean it has been demonstrated. Abiogenesis is still an assumption, but from a probabilistic point of view, there is currently no more probable supposition, and therefore we assume (for now) that abiogenesis must have been the way in which life began.

However, I see that you would be willing to consider viruses as living beings. If this is the case, the for you abiogenesis should be more than "possible", but almost a fact! Virus do not necessarily need a cell to reproduce, they just need a cell to replicate. To put it simple, if a virus parts its nucleic acid due to, ie, a momentary rise in temperature of the water, this nucleic acid is now two single strands of nucleic acid, compatible with other nucleic acids in the environment, and therefore likely to form new viruses, which is essentialy a reproducion process. If you apply this to viroids (virus lacking a proteinic capsid), then we can say that abiogenesis is a fact, since it is generally accepted that nucleic acids can arise spontaneously under certain conditions.

In my personal opinion, I'm skeptical to think that viruses or virioids are living entities, I prefer to label them as macromolecular complexes. The weakness of the hypothesis is that the jump from "life without protreins" to "life with proteins" is still difficult to figure out.
RoyLatham
Posts: 4,488
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11/11/2014 10:51:56 PM
Posted: 2 years ago
Miller-Urey is ancient history. The serious work on abiogenesis has been done since around 2000.

It is not necessary for genes to come together for a complex organism. What is required is for a molecule to replicate itself by drawing energy from the environment. That simpler than even a virus. One a molecule replicates, the mechanisms of evolution start operating. A mutation that provides a survival advantage will yield an improved molecule that has a comparative advantage over the unimproved version, taking more of the available energy to reproduce.

The evidence that abiogenesis is possible is that it appears to have happened at least once, producing live on earth. The alternative is that real magic happened. I don't believe in magic. It is possible that abiogenesis occurred somewhere else in the universe and was carried to earth by a comet or something. That's nonetheless one occurrence, and it's therefore possible.