How difficult is it for life to start?

[Ophiolite]

Thank you for pointing out that it is my opinion... I guess mine is inferior to all the other opinions being asserted in this thread with no support what so ever...

Opinions and assertions are different beasts, as you well know. Your opinion is the only one I noticed on this thread that was offered as an assertion.

[Jens]

http://www.nature.co...ws061113-9.html

 

Hello Moontanman. Thanks for providing more references.

(I really mean it. Let's not make a believe-battle out of it I did not want to attack you in any way. I just hated a bit the show part of the video.).

However, the first reference points to a text which explains even less than the video. The main reference I cannot find in google scholar:

Do you have more info on:

"Morowitz H.& Smith E., Santa Fe Institute Working Paper, (2006)"

 

Or is the second link you have provided intended to replace this non-existent reference?

 

 

Here some of the huge amount of articles published by Wächtershäuser, who is in favor of a systematic start of life and who really tries it the hard way (he has not convinced me at all, but you might find it interesting):

 

 

1. Wächtershäuser G (1990) Evolution of the first metabolic cycles. Proc Natl Acad Sci U S A 87: 200-204.

http://www.pnas.org/content/87/1/200.short

 

2. Wächtershäuser G (2000) Life as We Don't Know It. Science 289: 1307-1308.

http://ajdubre.tripod.com/Sci-Read-0/y-OriginLife-82500/OriginLifeSci-82500.html

 

3. Wächtershäuser G (2006) From volcanic origins of chemoautotrophic life to Bacteria, Archaea and Eukarya. Phil Trans R Soc B 361, 1787-1808. http://rstb.royalsocietypublishing.org/content/361/1474/1787.full

doi:10.1098/rstb.2006.1904

 

4. Wächtershäuser G (1994) Life in a ligand sphere. Proc Natl Acad Sci U S A 91: 4283-4287.

http://www.pnas.org/content/91/10/4283.short

 

 

 

I will try my way through the second reference you have provided the next weekend....

[Moontanman]

Hello Moontanman. Thanks for providing more references.

(I really mean it. Let's not make a believe-battle out of it I did not want to attack you in any way. I just hated a bit the show part of the video.).

However, the first reference points to a text which explains even less than the video. The main reference I cannot find in google scholar:

Do you have more info on:

"Morowitz H.& Smith E., Santa Fe Institute Working Paper, (2006)"

 

Or is the second link you have provided intended to replace this non-existent reference?

 

 

Here some of the huge amount of articles published by Wächtershäuser, who is in favor of a systematic start of life and who really tries it the hard way (he has not convinced me at all, but you might find it interesting):

 

 

1. Wächtershäuser G (1990) Evolution of the first metabolic cycles. Proc Natl Acad Sci U S A 87: 200-204.

http://www.pnas.org/content/87/1/200.short

 

2. Wächtershäuser G (2000) Life as We Don't Know It. Science 289: 1307-1308.

http://ajdubre.tripod.com/Sci-Read-0/y-OriginLife-82500/OriginLifeSci-82500.html

 

3. Wächtershäuser G (2006) From volcanic origins of chemoautotrophic life to Bacteria, Archaea and Eukarya. Phil Trans R Soc B 361, 1787-1808. http://rstb.royalsocietypublishing.org/content/361/1474/1787.full

doi:10.1098/rstb.2006.1904

 

4. Wächtershäuser G (1994) Life in a ligand sphere. Proc Natl Acad Sci U S A 91: 4283-4287.

http://www.pnas.org/content/91/10/4283.short

 

 

 

I will try my way through the second reference you have provided the next weekend....

 

 

Actually Ophiolite is correct, my opinion is just that an opinion. In this particular case I happen to be siding with someone who is not exactly well thought of in this area, Thomas Gold. His work along with others has convinced me that life forms easily and fast at great depth and pressure but I have to agree with Ophiolite in that i am not qualified to actually assert any of these things as true and the only honest answer is that we don't know.

 

Having said that I consider myself to be pretty good at logical thinking (i know a legend in my own mind) and to me the idea of metabolism first is the most logical alternative.

 

This stuff has been an intense interest of mine for most of my adult life, knowing some basic parts of several fields related to biology was and is a big part of the things I do as hobbies. I know most scientists have a rather low view of hobby types like myself, other than in astronomy, but I have managed to gain a small bit of respect from some real scientists in the tiny area that i have done work in. Admittedly that work is intensely focused on biological cycles that occur in nature and is for my own pleasure but a part of me requires that what i do be a bit more accurate than just guessing.

 

I am not qualified to argue this stuff beyond my own opinion...

 

I would like to say that the asinine cretin has a good point about bottlenecks in the evolution of life and the closer you look the more of them seem to appear. some that come to mind are the nickel, iron, methane, and oxygen bottle necks that occurred but life always seems to adapt and turn famine in to feast. We can only guess at the bottlenecks that might have appeared before life as we see it evolved on this planet.

[mississippichem]

I know most scientists have a rather low view of hobby types like myself, other than in astronomy, but I have managed to gain a small bit of respect from some real scientists in the tiny area that i have done work in. Admittedly that work is intensely focused on biological cycles that occur in nature and is for my own pleasure but a part of me requires that what i do be a bit more accurate than just guessing.

 

I think you actually seem to be quite knowledgeable in some areas. Don't down on yourself for not having a pedigree! I know I've had some fun speculating with you about exobiology anyway. Not that I know a damn thing about exobiology other than how general chemical principle might apply to it. Come to think of it...does anyone know anything about exobiology? So far we have a sample size of one with respect to abiogenesis.

Edited October 21, 2012 by mississippichem

[Moontanman]

I think you actually seem to be quite knowledgeable in some areas. Don't down on yourself for not having a pedigree! I know I've had some fun speculating with you about exobiology anyway. Not that I know a damn thing about exobiology other than how general chemical principle might apply to it. Come to think of it...does anyone know anything about exobiology? So far we have a sample size of one with respect to abiogenesis.

 

 

yeah, hard to draw a curve with one data point...

[Ophiolite]

Actually Ophiolite is correct, my opinion is just that an opinion. In this particular case I happen to be siding with someone who is not exactly well thought of in this area, Thomas Gold. His work along with others has convinced me that life forms easily and fast at great depth and pressure but I have to agree with Ophiolite in that i am not qualified to actually assert any of these things as true and the only honest answer is that we don't know.

Thank you for this acknowledgement. I wish to emphasise one of my opinions, but it is one I think can be logically demonstrated. You say that you are not qualified to make assertions on this issue. I maintain that no one is qualified, as yet, to make assertions on this issue. It is simply to dangerous to extrapolate from a sample size of one until and unless we can construct a detailed and plausible sequence of each event in the abiogenesis chain for which accurate probablities can be assessed. I think this achievable, but we are not presently there.

[STeve555]

Why would the start of life be difficult?

 

I might as well ask you "how easy is it for life to start?"

 

I like being semantic about this matter for this, however it is presumed dead as a doornail, belongs to quite an extent to the realm of philosophy.

And maybe to psychology, though be it backtracking interviews with the first chromosome-deranged ancient cells of old.

 

 

[Ophiolite]

A this stage the correct answer to both questions is "I don't know."

[Jens]

http://www.americans...rigin-of-life/1

 

Hi. As promised I read through the second link you provided. But unfortunately also in the written details there is not really more than in the film:

 

How can the authors talk about metabolism first without mentioning Wächtershäusers work? which is also based on the reverse citric cycle some years older and much more founded than what we read here.

 

In the section "Selection Begins" besides retorics there is not a single hint, how selection actually could work on a metabolic pathway (in contrast to Wächtershäuser) or what chemical selection actually is. So the real problem is not even theoretically addressed.

 

The "stranded electron" problem is nothing more than to tell that the system is not in equilibirum and there is free energy. The analogy example of of a pond sitting in top of a hill producing channels is just explaining positive feedback loops. But a positive feedback loop is not life. Chemical positive feedback loops are rare but not new. If somebody wants to explain life the next step from the positive feedback loop more into the direction of life needs to be explained. However, I do not see any input how you can come from a positive feedback loop to a system on which Darwinian evolution can start. But that is exactly the question to answer (or at least guessing) for all metabolism first theories.

 

The "paradox" treated in the section about thermodynamic and the solution to it is nothing more than the gibbs free energy: Yes, systems can go to lower entropy, if the same time energy is given to the environment (so that the overall entropy is actually always increasing). This is why the gibbs free energy was invented.

 

So finally all that is described are positive feedback loops like crystals, deepening river channels, flashes. And a claim that given a high energy starting point a chemical positive feedback loop (called channel) is enough to inevitably start life. That is not much. (Note: Fire is also a chemical positive feedback loop, a TNT explosion, too).

 

....so for the topic "metabolism first" I recommend reading Wächtershäuser (even if it is obviously much less entertaining ) greetings, Jens

 

 

[kevina]

Ive just finished a open Uni course which was aimed at the environment however it touched on this subject.

 

The majority of life requires sunlight in whatever form plant or animal and indeed this is the majority of life on this planet. However in the deep seas there is quite a lot of microscopic life situated around geothermal vents under incredible pressures and if I remember correctly also plant and animal life aswell.

 

On a random note these geothermal vents have been found on Jupiters moons and are believed to have existed on mars. This pretty much meets the requirements for life to exist all that's missing is that "spark" or meteor and a few million years of baking in the oven.

Edited October 30, 2012 by kevina

[Misfolded Protein]

The difficulty with this question is that we have a sample size of 1 for the phenomena of 'life'. We do have many theories about how life came about, the RNA world hypothesis for one, but there are others too; the problem with all of them is that we still haven't been able to take theory and turn it into a successful experiment (i.e. no life has been made from any 'soup' of inorganic and organic molecules)...with that in mind, here is the way i see it

 

One thing that does stand out for me is that life began almost as soon as it could, probably about 3.8 billion years ago. This at least suggests that life, given the right conditions (habitable zone + water + organic molecules), can take hold with reasonable ease. There are probably a number of things that need to come together for life to begin; it's weather or not these conditions come together in the right way that may be uncommon...or perhaps a short timeframe for life to happen, if the conditions wait too long and the planet cools too quickly, then the necessary reactions might not take place.

So it may be easy for life to start, but all the necessary conditions, at the right time, in the right place, may be uncommon... Another thing, it also can't be too easy because, as far as we can tell, life only arose once here on Earth.

 

Or, maybe life takes hold rather easily, but the evolution of complex life is difficult; it did take about 1.5 billion years for eukaryotic cells to appear. Just so it's clear, that is a VERY long time!! Consider how bacteria multiply and evolve, think of how many generations and genetic permutations these microbes must have gone through before the right cells came together.

 

All in all, I think that life, especially complex life, to begin is probably a rare event...but it really is difficult to say......

[Ophiolite]

One thing that does stand out for me is that life began almost as soon as it could, probably about 3.8 billion years ago. This at least suggests that life, given the right conditions (habitable zone + water + organic molecules), can take hold with reasonable ease.

It is, however, equally supportive of the notion of pan spermia.

[StringJunky]

It is, however, equally supportive of the notion of pan spermia.

 

Talking about pan spermia is an irrelevant distraction i think because it does not address how life started. It only hypothesizes how life may have arrived on Earth in the absence of it starting on it.

[CharonY]

It is relevant to Misfolded Protein's assertion regarding the timing. If panspermia happened, the time frame needed for abiogenesis could be extended.

[Misfolded Protein]

It is relevant to Misfolded Protein's assertion regarding the timing. If panspermia happened, the time frame needed for abiogenesis could be extended.

 

 

While i can see that it wouldn't make it harder for panspermia to occur, i don't think that it supports it either. It doesn't really address how difficult it would be for life to start from scratch either....it just relegates the problem to how life started on another planet (and then made the miraculous journey and inseminated Earth).

[Ophiolite]

Talking about pan spermia is an irrelevant distraction i think because it does not address how life started. It only hypothesizes how life may have arrived on Earth in the absence of it starting on it.

It is not irrelevant, but wholly germane. The assertion was made that the early appearance of life on the Earth pointed towards abiogenesis being a 'simple' process, since it occured quickly. That is an invalid inference, whose invalidity is demonstrated by noting an alternative explanation, in this case pan spermia. I am not proposing we now discuss pan spermia in this thread -that might be irrelevant. I am stating that we cannot use the early appearance of life on Earth as supporting a rapid timing for abiogenesis.

[Moontanman]

Panspermia, I have some mixed ideas on this premise. Lets say life is very difficult to form, and lets say the Earth is a typical "Earth Like" planet. How much biological material is ejected from the earth in a million years? How many planets with life ejecting X amount of material on average in a million years would have to form life abiogenetically before the earth would have a reasonable expectation of receiving a enough biological material to form life so quickly in it's history?

 

I have to say even in the absence of solid data that sounds like another very difficult thing to happen, so we would just be replacing one mysterious thing with another mysterious thing...

 

On the other hand it seems probable that even complex life forms can be transferred from one planet to another inside a solar system. Some plant and even animals could be transferred that way... water bears, maybe brine shrimp, plant spores and even seeds.

 

If there were more than one life friendly planet in our solar system I would expect to see some mingling of the biospheres...

 

http://www.planetary.org/explore/projects/life/

 

https://sites.google.com/site/evolutionarylifeorigins/theory-of-panspermia

[StringJunky]

It is not irrelevant, but wholly germane. The assertion was made that the early appearance of life on the Earth pointed towards abiogenesis being a 'simple' process, since it occured quickly. That is an invalid inference, whose invalidity is demonstrated by noting an alternative explanation, in this case pan spermia. I am not proposing we now discuss pan spermia in this thread -that might be irrelevant. I am stating that we cannot use the early appearance of life on Earth as supporting a rapid timing for abiogenesis.

 

OK, point taken.