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A.DIM
2007-Oct-03, 11:55 AM
What are the accepted evidences that a complex prebiotic chemical soup actually existed on Earth?

Ronald Brak
2007-Oct-03, 12:01 PM
The fossilized cans of Campbells Primordial Soup?

WaxRubiks
2007-Oct-03, 12:06 PM
Yes, they were found beneith the KeTchup boundary weren't they?

Ronald Brak
2007-Oct-03, 12:19 PM
More seriously, I guess it depends on what you mean by primordial soup. At the moment it is generally thought that life could have started in one of numerous "self-complicating" chemical systems, If you magically took all life away from the earth you'd get interesting collections of chemicals in all sorts of places such as hot springs, deep sea vents, clay beds and so on. Take away free oxygen and there will be additional interesting chemistry that can take place in its absence. So I guess it would be more of a question of why wouldn't various chemical "soups" or areas of complex chemical reactions appear.

jlhredshift
2007-Oct-03, 12:58 PM
The primordial soup would not be fossilized. Virtually everything around you is oxidised, or trying to get that way; rust on your car. The only method of producing large amounts of free oxygen that we know of is life, and we can measure the effects of that in the rock record.

Noclevername
2007-Oct-03, 01:06 PM
The primordial soup would not be fossilized. Virtually everything around you is oxidised, or trying to get that way; rust on your car.

Not to mention that said oxygen has a tendency to destroy or change many of the organic chemicals that would leave geological records. That many years of corrosive atmosphere takes its toll.

R.A.F.
2007-Oct-03, 01:14 PM
This (http://abob.libs.uga.edu/bobk/ccc/ce031300.html) is interesting.



The panspermia hypothesis has to contend with major objections. As the oldest signatures of life occur in 3.8*10^9 years-old rocks, importation
of bacteria to Earth would have taken place during the so-called Late Heavy Bombardment (4.2-3.8*10^9 years ago), represented by mare basins on the Moon, when life anywhere in the solar system would have been under enormous stress. It has never been explained how proteins can escape prolonged cosmic radiation without fatal consequences. Bacteria older than the 2.0*10^9 years-old Gunflint chert, Minnesota, are not known to have cell walls or form spores, and may not have been capable of space transport. Viruses, which can occur in a frozen crystallised state, contain DNA or RNA but never contain both, and are thus incapable of reproduction except as parasites within a living host. Despite intensive studies, the essential molecules of life - DNA, RNA, ATP and ADP (adenosine tri- and di-phosphate) are not found in meteorites, whose carbon isotopic composition is heavier than in life remnants represented by kerogen. Amino acids found in carbon-rich chondritic meteorites - isobutaric acid and racemic isovaline, believed to have been shock-modified during deep space impacts, are exceedingly rare on Earth - a key observation militating against 'panspermia'.

Cougar
2007-Oct-03, 02:06 PM
What are the accepted evidences that a complex prebiotic chemical soup actually existed on Earth?
Lab experiments. (http://www.tufts.edu/as/wright_center/cosmic_evolution/docs/fr_1/fr_1_chem5.html)

A.DIM
2007-Oct-03, 03:27 PM
This (
http://abob.libs.uga.edu/bobk/ccc/ce031300.html) is interesting.

MODERATORS:

Please remove RAF's response from this thread as it in no away addresses my question. Perhaps he'd like his own thread in a more appropriate forum?

My aim here is to restrict my involvement to only the question and read the answers given.
Of course, I'd like them to be relevant.

Much appreciated.

R.A.F.
2007-Oct-03, 03:55 PM
The mods will do what they will do but in the meantime I think I'll post that link on your other panspermia thread...certainly no harm in that. :)

Celestial Mechanic
2007-Oct-03, 03:58 PM
I think RAF's response is relevant to this thread, which appears to be an attempt to prop up panspermia by trying to knock out arguments for Earth-based origin of life. If life really did originate off-planet, there should be some evidence for it in the Solar System. RAF's response seems to indicate strong arguments against.

Jim
2007-Oct-03, 04:10 PM
MODERATORS:

Please remove RAF's response from this thread as it in no away addresses my question. Perhaps he'd like his own thread in a more appropriate forum?

My aim here is to restrict my involvement to only the question and read the answers given.
Of course, I'd like them to be relevant.

Much appreciated.

A.DIM, you should really use the report function for such requests.

If R.A.F. wants his post deleted, I will oblige. It may or may not be off topic, but it doesn't seem offensive, so it's his call. If you consider it off topic, you can always ignore it.

(BTW, it's interesting that you mentioned R.A.F.'s post and said nothing about Ronald Brak's or Frog march's.)

A.DIM
2007-Oct-03, 04:13 PM
I think RAF's response is relevant to this thread, which appears to be an attempt to prop up panspermia by trying to knock out arguments for Earth-based origin of life. If life really did originate off-planet, there should be some evidence for it in the Solar System. RAF's response seems to indicate strong arguments against.

Indeed the question arose out of "The Feather Onion" thread but RAF's response is merely tangential at best, and offers no answer to my question whatsoever.

This is Q&A, right?

A.DIM
2007-Oct-03, 04:19 PM
A.DIM, you should really use the report function for such requests.

I will do so in the future.


If R.A.F. wants his post deleted, I will oblige. It may or may not be off topic, but it doesn't seem offensive, so it's his call. If you consider it off topic, you can always ignore it.

IMO, it is off topic.

If he wants to present an argument against panspermia, there are far more appropriate places, no?


BTW, it's interesting that you mentioned R.A.F.'s post and said nothing about Ronald Brak's or Frog march's.)

Well, those seemed like the usual initial quips one often reads, and after Ronald Brak profered "more seriously" I was ok with that.

As I said, if RAF wants to present an argument against panspermia I think there are better options than this thread.

I appreciate those who've given relevant answers thus far.

R.A.F.
2007-Oct-03, 04:24 PM
This is Q&A, right?

Certainly, but can you explain why you didn't ask the question as Ronald Brak did:


...I guess it would be more of a question of why wouldn't various chemical "soups" or areas of complex chemical reactions appear.

The way you asked your question makes it appear as if you already know what answer you "want". As if you have already reached a conclusion before you asked the question.

...and we all know that's not how science "works". :)

antoniseb
2007-Oct-03, 04:39 PM
What are the accepted evidences that a complex prebiotic chemical soup actually existed on Earth?
Aside from the fact that there is life here on Earth now, and that we have seen the spectral signatures of many organic molecules in space, and in C-type meteorites, we don't have direct evidence that it was here. There is no fossil evidence for it. Still it is the current most-likely-mainstream model for how things got started.

As R.A.F. pointed out there are people who support the panspermia idea, but the fact is that even if there was panspermia, it would have needed some prebiotic soup to be able to grow new organisms.

R.A.F.
2007-Oct-03, 04:57 PM
IMO, it is off topic.

Boy, there simply is no "pleasing" you is there? I've heard complaint after complaint from you that I "personalize" my arguments against you in particular, (and I'll admit that I've "fallen off" that wagon occasionally), yet when I take a "page" from your "book" and post a link that is actually about the subject being discussed, panspermia, it is suddenly "off topic". I also notice that you haven't attempted to refute what is said on the link, you just wanted it "gone".


If he wants to present an argument against panspermia, there are far more appropriate places, no?

I did post it on your other panspermia thread. Will you be responding to it there?


I appreciate those who've given relevant answers thus far.

Why thank you.

A.DIM
2007-Oct-03, 08:33 PM
Certainly, but can you explain why you didn't ask the question as Ronald Brak did:

I have to explain why I didn't ask my question as someone else might?

Ridiculous!

My question is very specific.

Ronald Brak's question is not, in essence saying "why wouldn't chemical soups appear? we can assume they did and so no reason to ask for the evidence."

Is that how science works?


The way you asked your question makes it appear as if you already know what answer you "want". As if you have already reached a conclusion before you asked the question.

Rubbish.

The question is clear and concise.


...and we all know that's not how science "works". :)

Certainly not, given that your starting assumption is wrong.
You're assuming I already "know" the answer I "want," that I've reached a "conclusion."
Each of these based on how it "appears" to you.

Is that how science works, RAF?

A.DIM
2007-Oct-03, 08:35 PM
Aside from the fact that there is life here on Earth now, and that we have seen the spectral signatures of many organic molecules in space, and in C-type meteorites, we don't have direct evidence that it was here. There is no fossil evidence for it. Still it is the current most-likely-mainstream model for how things got started.

Thanks, another good answer to my question.


As R.A.F. pointed out there are people who support the panspermia idea, but the fact is that even if there was panspermia, it would have needed some prebiotic soup to be able to grow new organisms.

That may be, but I still find it irrelevant to this thread.

Neverfly
2007-Oct-03, 08:36 PM
Sometimes evidence is found in logic.

Life had to have had a starting point.
If that starting point wasn't the primordial soup on Earth but was panspermia, then that means there must have been a primordial soup somewhere else for it to be transported here.

It becomes like looking in a mirror with another mirror behind you. Infinite appearance.

A.DIM
2007-Oct-03, 08:42 PM
Boy, there simply is no "pleasing" you is there? I've heard complaint after complaint from you that I "personalize" my arguments against you in particular, (and I'll admit that I've "fallen off" that wagon occasionally), yet when I take a "page" from your "book" and post a link that is actually about the subject being discussed, panspermia, it is suddenly "off topic". I also notice that you haven't attempted to refute what is said on the link, you just wanted it "gone".

Totally wrong.
The topic here is the accepted evidences for a primordial soup on Earth, not panspermia.
I realize it may difficult for you to separate them considering the question came out of a panspermia thread but please try.

And note that I did suggest your link be posted elsewhere more appropriate, not that I "just wanted it gone" as you say.
And I'll definitely be checking it out provided the link works; as it is, a quoted paragraph with no cites hardly finalizes the debate.


I did post it on your other panspermia thread. Will you be responding to it there?

Does it work there?


Why thank you.

Irrelevant.

R.A.F.
2007-Oct-03, 08:43 PM
You're assuming I already "know" the answer I "want," that I've reached a "conclusion."

Actually, that's not an assumption...that is something I know.


...I still find it irrelevant to this thread.

You are of course entitled to that opinion no matter how many other people disagree with it.

R.A.F.
2007-Oct-03, 08:48 PM
...provided the link works...

Why in the hell would you post that?? Ya don't have to attack everything I say, do you??

Guess I had better "let you be" for a while...looks like you're getting ready to "blow a gasket". :)

A.DIM
2007-Oct-03, 08:58 PM
Actually, that's not an assumption...that is something I know.

Oh yeah?

Please tell me what I "know" or "want" and the "conclusion" I've drawn.


You are of course entitled to that opinion no matter how many other people disagree with it.

Appeal to popularity?

ExpErdMann
2007-Oct-03, 09:00 PM
On a more technical note, the notion of "primordial soup" for the origins-of-life set means the idea that organic biomolecules somehow formed on the primitive earth, were dissolved in water and then interacted randomly to form more complex biomolecules and then cells. The scenario is termed "heterotrophic", since the chemical system gets free inputs of already complicated molecules such as amino acids. This model was dominant for many years, but has gradually been challenged by different scenarios which envisage that life arose autotrophically (ie, without 'free' amino acids, etc.) on mineral surfaces. The most famous name here is Gunter Wachtershauser, who argues that the initial biosystems were chemoautotrophic, using reduced chemical compounds as an energy source. Alternative photoautotrophic models using light have also been proposed. The advantage of the mineral surface models is that the chemical interactions could be less random. They would be more analogous to a developing embryo. There is no fossil evidence for any of these scenarios. Panspermia cannot be ruled out, but it is far less likely than the earth-based models.

A.DIM
2007-Oct-03, 09:01 PM
Why in the hell would you post that?? Ya don't have to attack everything I say, do you??

Guess I had better "let you be" for a while...looks like you're getting ready to "blow a gasket". :)

I've been trying to access the link for some time now.
It doesn't work.
You asked if I'd be replying and I told you I will be "provided the link works."

And you feel attacked by that?

Perhaps checking one's oil pressure would be prudent.

I'm level.

Professor Mayhem
2007-Oct-03, 09:06 PM
Good resources here, (http://en.wikipedia.org/wiki/Origin_of_life) here, (http://www.talkorigins.org/faqs/abioprob/originoflife.html#synthesis) and here. (http://www.gla.ac.uk/projects/originoflife/html/2001/laymans_abstract.htm)

Celestial Mechanic
2007-Oct-03, 09:09 PM
I've been trying to access the link for some time now.
It doesn't work.
You asked if I'd be replying and I told you I will be "provided the link works."

And you feel attacked by that?

Perhaps checking one's oil pressure would be prudent.

I'm level.
With a bit of luck this link (http://abob.libs.uga.edu/bobk/ccc/ce031300.html) should work. I had to remove a few superfluous characters from the beginning of the URL that was given.

Van Rijn
2007-Oct-03, 09:09 PM
Ronald Brak's question is not, in essence saying "why wouldn't chemical soups appear? we can assume they did and so no reason to ask for the evidence."

Is that how science works?


Did you read Couger's lab experiments link? Given the chemicals and the conditions we can experiment and see what would happen. Hence, "prebiotic soup."

R.A.F.
2007-Oct-03, 09:13 PM
Thanks, CM.

FYI...I have fixed the link on both threads.

CodeSlinger
2007-Oct-03, 09:38 PM
A.DIM,

I'd like to see what you think of the answers you've already received (jlhredshift at post 5, Noclevername at post 6, Cougar at post 8, and so on down the line). Do you consider your question answered? If this thread is about the accepted evidence for "primordial soup", how about spending less time bickering with R.A.F. and more time on the question itself?

Jim
2007-Oct-03, 09:58 PM
(H)ow about spending less time bickering ... and more time on the question itself?

Good advice for both A.DIM and R.A.F. Quit finding fault and picking nit and discuss the topic, "What evidence is there for a primordial soup?"

(If I didn't know better, I'd swear you two were married.)

A.DIM
2007-Oct-03, 11:09 PM
A.DIM,

I'd like to see what you think of the answers you've already received (jlhredshift at post 5, Noclevername at post 6, Cougar at post 8, and so on down the line). Do you consider your question answered?

Yes, the question is largely answered.
All but a few posters gave pertinent info.


If this thread is about the accepted evidence for "primordial soup", how about spending less time bickering with R.A.F. and more time on the question itself?

Indeed.

As I said before, my involvement here was intended to be restricted to only asking the question, not even discussing the merits of the evidences given.

Professor Mayhem
2007-Oct-04, 05:16 PM
More links:

- A resource page (http://web99.arc.nasa.gov/~astrochm/originlinks.html) from NASA Ames regarding Exobiology, Astrobiology, and the origin of life.

- Berkeley Biology's (http://evolution.berkeley.edu/evosite/evo101/IIE2aOriginoflife.shtml) section on the origin of life.

- Another good resource. (http://www.resa.net/nasa/origins_life.html)

- A more detailed summary (http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/AbioticSynthesis.html) of Miller's experiments.

- A good read on paleobiology. (http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookpaleo2.html)

Jerry
2007-Oct-04, 05:35 PM
Good advice for both A.DIM and R.A.F. Quit finding fault and picking nit and discuss the topic, "What evidence is there for a primordial soup?"

From a broad prospective, the whole topic is a nit pick. We have a ordered fossil record that starts with very tiny stuff that gradually gets bigger. We have good evidence that the atmosphere was once reducing; and then became oxidizing. What was life like on a reducing planet? Flood the world with ammonia, scrub out all the oxygen, and wait a few millennia. Some adaptive, reproductive coded structure will likely rise that we would recognize as a life form, but we would not be around to see it.

astromark
2007-Oct-04, 06:36 PM
I seem to recall that good evidence exists to support this notion of life evolving from a primordial swamp. The nuts and bolts of this argument are well documented. The fact that some will not recognize this as fact might have more to do with preconceived doctrines of faith rather than science.
Amicable argument is always interesting if not destructing from the question itself. Not shooting the messenger. Encouraging the debate. mark.

Jerry
2007-Oct-04, 08:27 PM
Well, from one of Professor Mayhems references:


In the years since Miller's work, many variants of his procedure have been tried. Virtually all the small molecules that are associated with life have been formed:

17 of the 20 amino acids used in protein synthesis, and
all the purines and pyrimidines used in nucleic acid synthesis.

But abiotic synthesis of ribose and thus of nucleosides has been much more difficult.

One difficulty with the primeval soup theory is that it is now thought that the atmosphere of the early earth was not rich in methane and ammonia essential ingredients in Miller's experiments.

A lot of time has passed since the 17 amino acid showed up in an gungy organic synthesis vat. It is fair to argue there has not been much recent progress. It is also fair to argue progress towards the 'accidental creation of nucleotides' should not be expected.

We only have one known successful family of replicators - all life forms are related. How many eons did the natural world gurgle away before even one replicating pair of anything occurred?

These are fun questions to ask, speculate, and experiment with, but we know whatever happened to create life was a rare and unique event - even if it did involve pan0spermia. Don't expect 'good' answers any time soon...Meanwhile, set up your vat and start gurgling...

Van Rijn
2007-Oct-04, 08:38 PM
These are fun questions to ask, speculate, and experiment with, but we know whatever happened to create life was a rare and unique event - even if it did involve pan0spermia. Don't expect 'good' answers any time soon...Meanwhile, set up your vat and start gurgling...

I don't think we do know how rare such an an event is. The scale of current experiments is very small compared to an entire world of experiments that would have been taking place on the early Earth. At some point, we may find that the start of life is very rare, or we might find that it is actually very common, but once life starts, it's difficult for others to develop and compete.

There are ongoing experiments to develop simple life forms in the lab, and some think they're progressing. We might be able to tighten up some parameters on this question in a few years. What we eventually do (or don't) find with advanced telescopes could also help with this question.

Ronald Brak
2007-Oct-05, 09:52 AM
A lot of time has passed since the 17 amino acid showed up in an gungy organic synthesis vat. It is fair to argue there has not been much recent progress. It is also fair to argue progress towards the 'accidental creation of nucleotides' should not be expected.

Well no, vast strides have been made since then. Miller's experiment was performed in the same year that Watson and Crick with some help from a woman that no one remembers discovered the structure of DNA. Now that we have a good understanding of DNA we know a lot about how it didn't come about and we have plenty of ideas on how it might have. Now no one thinks DNA was formed by chance instead ways that pre-DNA life could have developed are being investigated. This life then went on to learn the trick of using DNA.

grant hutchison
2007-Oct-05, 10:13 AM
Miller's experiment was performed in the same year that Watson and Crick with some help from a woman that no one remembers discovered the structure of DNA.Rosalind Franklin.
For some reason she has become more famous for "never being remembered" than for her role in the DNA discovery. :)

Grant Hutchison

Professor Mayhem
2007-Oct-05, 03:32 PM
The science is still very much in its infancy. Harvard (http://origins.harvard.edu/) recently threw its hat in the ring by kicking off a prolonged initiative (http://www.news.harvard.edu/gazette/2006/11.09/11-origins.html) to study the origin of biological life.

Neverfly
2007-Oct-05, 05:23 PM
Well no, vast strides have been made since then. Miller's experiment was performed in the same year that Watson and Crick with some help from a woman that no one remembers discovered the structure of DNA. Now that we have a good understanding of DNA we know a lot about how it didn't come about and we have plenty of ideas on how it might have. Now no one thinks DNA was formed by chance instead ways that pre-DNA life could have developed are being investigated. This life then went on to learn the trick of using DNA.

<chuckle>
I'm with Grant Hutchinson on this one...
Rosalind Franklin is remembered and had I forgotten her name in grade school science class my (male) teacher would have used a yard stick to refresh my memory.