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iquestor
2013-Sep-15, 08:25 PM
From an article (http://www.cnn.com/2013/09/13/opinion/urry-voyager-spacecraft/index.html?hpt=hp_t4)on CNN.com




If "E.T." finds Voyager 1, will it phone home? We know that planets around other stars ("exoplanets") are abundant, and that when liquid water and carbon-based compounds and an energy source are present, life arises easily. But the kind of intelligent life that can build and launch a pioneering spacecraft is surely much more rare.

more... (http://www.cnn.com/2013/09/13/opinion/urry-voyager-spacecraft/index.html?hpt=hp_t4)

Um... how can they say that "Life Arises Easily..." ??? [bold in quote, mine] -- Have we done it in a lab? what am I missing here??

R.A.F.
2013-Sep-15, 08:44 PM
what am I missing here??

Well, it is labled as an "opinion" piece. :)

Selfsim
2013-Sep-15, 08:52 PM
Its a classic example of "The Sea Monkey" (http://en.wikipedia.org/wiki/Sea_monkeys) delusion! .. Just add water to the packet of magic stuff and bingo! ..Those pesky things appear within days .. right before your very eyes!

(Oh, and it has a cult following (http://en.wikipedia.org/wiki/Sea_monkeys#In_popular_culture) too, y'know!)

iquestor
2013-Sep-15, 10:07 PM
well, it is labled as an "opinion" piece. :)
lol!

Swift
2013-Sep-16, 01:58 AM
Originally Posted by iquestor
what am I missing here??Well, it is labled as an "opinion" piece. :)
Yes. And CNN is trying to sell copy (or page views)

iquestor
2013-Sep-16, 10:57 AM
the Author is a professor of Physics, At Yale....

Selfsim
2013-Sep-16, 11:12 AM
the Author is a professor of Physics, At Yale....Yeah .. its a shocker, eh?
Hows this for the leading contender for the biggest non-statement of the year ...

In terms of receiving signals, Earth-bound and near-Earth telescopes are unsurpassed.
:scope:

iquestor
2013-Sep-16, 12:01 PM
my favorite from a UFO Coverup paperback:

"While the lack of evidence only serves to heighten the mystery,..."

Delvo
2013-Sep-18, 02:57 AM
Laboratories have observed spontaneous generation of microscopic lipid spheroids they call "vacuoles". These things consist of a fatty acid outer layer closed on itself, separating the water inside from the water outside, which incorporates stray fatty acids it bumps into (including not just monomers but alsmaller vacuoles) and thus keeps growing larger. Nucleic and amino acids in the same solution don't form objects this big on their own but can also polymerize, and any that happen to do so inside a vacuole can't get out, so the concentration inside vacuoles tends to increase above surrounding levels. This causes more water and organic acid monomers to be drawn in, which makes the vacuole grow. When a vacuole gets too big to hold together against the water's movements, it breaks, but the lipids' cohesion makes it do so by pinching off in a way that results in two smaller, intact, closed vacuoles.

So we have closed lipid membranes containing a dense concentration of organic compounds in water, which grow, divide, and eat each other, all practically immediately (well within the time frame that an individual lab & its staff can record) once you combine the right ingredients at the right temperature. I'd call that life, and I'd call it pretty easy.

Selfsim
2013-Sep-18, 03:37 AM
Laboratories have observed spontaneous generation of microscopic lipid spheroids they call "vacuoles". These things consist of a fatty acid outer layer closed on itself, separating the water inside from the water outside, which incorporates stray fatty acids it bumps into (including not just monomers but alsmaller vacuoles) and thus keeps growing larger. Nucleic and amino acids in the same solution don't form objects this big on their own but can also polymerize, and any that happen to do so inside a vacuole can't get out, so the concentration inside vacuoles tends to increase above surrounding levels. This causes more water and organic acid monomers to be drawn in, which makes the vacuole grow. When a vacuole gets too big to hold together against the water's movements, it breaks, but the lipids' cohesion makes it do so by pinching off in a way that results in two smaller, intact, closed vacuoles.

So we have closed lipid membranes containing a dense concentration of organic compounds in water, which grow, divide, and eat each other, all practically immediately (well within the time frame that an individual lab & its staff can record) once you combine the right ingredients at the right temperature. I'd call that life, and I'd call it pretty easy.Lipids, fatty acids and organic acids are all produced by life. Has anyone yet described the process in nature which produces these products from inorganic chemical reactions?

Don J
2013-Sep-18, 04:42 AM
Lipids, fatty acids and organic acids are all produced by life. Has anyone yet described the process in nature which produces these products from inorganic chemical reactions?
http://exploringorigins.org/fattyacids.html


FORMING FATTY ACIDS ON THE EARLY EARTH

How might fatty acids have formed on the early Earth? Some scientists have proposed that hydrothermal vents may have been sites where prebiotically important molecules, including fatty acids, were formed. The animation on the left shows a theoretical scenario in which fatty acids are formed along the face of a geyser. Research has shown that some minerals can catalyze the stepwise formation of hydrocarbon tails of fatty acids from hydrogen and carbon monoxide gases -- gases that may have been released from hydrothermal vents. Fatty acids of various lengths are eventually released into the surrounding water.

The fatty acids produced in this manner would only be found in low concentrations. Relatively high concentrations of fatty acids are required, however, to form higher order structures such as micelles and vesicles. Pools of water may have slowly accumulated fatty acids through cycles of shinkage by evaporation and growth by the delivery of additional dilute fatty acid solution. It is also possible that droplets of fatty acids may have become aerosolized, as shown in the animation on the left, allowing the dry fatty acid particulate to travel long distances away from its original site of synthesis. Over time, small pools of water may have accumulated high concentrations of fatty acids

Selfsim
2013-Sep-18, 05:04 AM
http://exploringorigins.org/fattyacids.htmlSpeculative and hypothetical … a simulation only.

Last time I looked, Szostak was positing stearic and oleic acids, which are long chain organics (18 carbon atoms) to begin with. I'm still yet to hear of a finding showing production of such acids from inorganics in a natural environment. (Ie: 'show me the geyser where this actually happens').

Don J
2013-Sep-18, 06:38 AM
Speculative and hypothetical … a simulation only.

Last time I looked, Szostak was positing stearic and oleic acids, which are long chain organics (18 carbon atoms) to begin with. I'm still yet to hear of a finding showing production of such acids from inorganics in a natural environment. (Ie: 'show me the geyser where this actually happens').
That may be the reason why the title of the article is:
FORMING FATTY ACIDS ON THE EARLY EARTH, the objective is trying to explain the process leading to the origin of the first primitive cell. You know what happened after...
-----
Talking about Szostak and his Harvard team,

Harvard Team Zeroing in on How Life Arose from Nonliving Molecules
August 29, 2009
http://polynomial.me.uk/2009/08/29/harvard-team-zeroing-in-on-how-life-arose-from-nonliving-molecules/
Excerpts


Building on earlier work by other scientists, Szostak and colleagues began experimenting with a clay mixture common on early Earth called montmorillonite, which was found to catalyze the chemical reactions needed to make RNA.
....
So, did life originally spring from clay as some creation myths assert? Not necessarily, but it does provide a possible mechanism for explaining how life initially arose from nonliving molecules. Szostak’s team at the Howard Hughes Medical Institute and Massachusetts General Hospital showed that the presence of clay aids naturally occurring reactions that result in the formation of fatty sacks called vesicles, similar to what scientists expect the first living cells to have looked like. Further, the clay helps RNA form. The RNA can stick to the clay and move with it into the vesicles. This provides a method for RNA’s critical genetic information to move inside a primitive cell.

“It’s exciting because we know that a particular clay mineral helps with the assembly of RNA,” Szostak said. “There certainly would have been lots of environments on early Earth with clay minerals. It’s something that forms relatively easily as rocks weather.”

The researchers also found that the clay expedited the process by which fatty acids form vesicles that could serve as cell membranes. When RNA and fatty acids were mixed with the montmorillonite, the clay seemed to help transport the RNA inside the vesicles, forming a cell-like structure. Szostak and his team surmised that a similar process could possibly have led to the creation of the first cell.

Selfsim
2013-Sep-18, 06:58 AM
That may be the reason why the title of the article is:
FORMING FATTY ACIDS ON THE EARLY EARTH, the objective is trying to explain the process leading to the origin of the first primitive cell. You know what happened after...
-----
Talking about Szostak and his Harvard team,

Harvard Team Zeroing in on How Life Arose from Nonliving Molecules
August 29, 2009
http://polynomial.me.uk/2009/08/29/harvard-team-zeroing-in-on-how-life-arose-from-nonliving-molecules/
ExcerptsShow me an RNA molecule on Mars.
... After all, that's where all the right things supposedly are .. including the clays ...
If is all 'likely', then that's where 'all the action will be', no?

Don J
2013-Sep-18, 07:20 AM
Show me an RNA molecule on Mars.
... After all, that's where all the right things supposedly are .. including the clays ...
If is all 'likely', then that's where 'all the action will be', no?
Here some clues about possible Martian meteorites contribution:
http://news.discovery.com/space/asteroids-meteors-meteorites/mars-meteorite-life-building-blocks-130617.htm


Scientists have found a potential building block for life in a Martian meteorite recovered from Antarctica.
Parts of the rock contain rich concentrations of boron, which biochemists suspect played a key role in the development of ribonucleic acid, or RNA.

“I had read how important boron could have been in the origins of life, stabilizing a part of RNA,” biologist James Stephenson, with the NASA Astrobiology Institute at the University of Hawaii told Discovery News.

As for the clay here how it formed on Earth:
http://polynomial.me.uk/2009/08/29/harvard-team-zeroing-in-on-how-life-arose-from-nonliving-molecules/


When the Earth and Moon were cooling from the forces of accretion, no doubt there would have been thousands of volcanic ash plumes blooming in the proto-atmosphere, as the brittle mantle overflowed with hot magma and molten rock… And as the Earth’s surface cooled, water would have condensed out from the atmosphere and dissolved some of the ash. This would have begun the cycle of accumulation of this clay, as it deposited in ever increasing amounts over the surface of the Earth.

Selfsim
2013-Sep-18, 09:11 AM
Here some clues about possible Martian meteorites contribution:
http://news.discovery.com/space/asteroids-meteors-meteorites/mars-meteorite-life-building-blocks-130617.htm

As for the clay here how it formed on Earth:
http://polynomial.me.uk/2009/08/29/harvard-team-zeroing-in-on-how-life-arose-from-nonliving-molecules/All the 'right' building blocks .. all the 'right' clays ... all the 'right' conditions ... but not a single hint of RNA on Mars ... and yet, 'life arises easily when liquid water and carbon-based compounds and an energy source are present', eh(?)
:confused:

iquestor
2013-Sep-18, 12:09 PM
All the 'right' building blocks .. all the 'right' clays ... all the 'right' conditions ... but not a single hint of RNA on Mars ... and yet, 'life arises easily when liquid water and carbon-based compounds and an energy source are present', eh(?):confused:

I emailed the author,


Ms. Urry,

I enjoyed your CNN article on Voyager, but I have a question based on the following underlined sentence from your article:

“ If "E.T." finds Voyager 1, will it phone home? We know that planets around other stars ("exoplanets") are abundant, and that when liquid water and carbon-based compounds and an energy source are present, life arises easily. But the kind of intelligent life that can build and launch a pioneering spacecraft is surely much more rare. “

How do we know such a thing? We know of no other living biospheres, and haven’t achieved abiogenesis in a lab, so how can you say that “life arises easily”? What am I missing?
(If you guys have found Life on Mars and haven’t told us, I am going to be seriously mad. ;) )



and she replied thusly:

Meg Urry wrote:


You ask a thoughtful question and of course we don't know anything about life arising on other planets, but my comment was based on the abundance of life around the Earth, even in very inhospitable zones that would not previously have been imagined to support life – for example, near thermal vents deep in the ocean or in the driest parts of Antarctica. For the past 15 years, the astrobiology community has held a series of meetings and workshop on the definition of life, how to characterize it, where it is found, etc., and my comment that "life arises easily" is based on their extensive research. Wherever there is liquid water (even in the interstices between ice crystals) and an energy source, life exists on Earth. You can think of that as one data point or as many, given the many places living cells appear. More controversial is the notion that life once existed on Mars (the Martian meteorite), though we may know more soon, with the Mars Science Laboratory.
In any case, I was very inspired when I read about the Urey-Miller experiments many years ago, and given that the Earth is 4.5 billion years old, and the first life probably arose around 3.5 billion years ago, it seems very likely that life happens without too much difficulty. But I would also be the first to say this has not yet been proved to be true.

I understand where she is coming from, but life being found in even inhospitable zones isnt abiogeneis, its adaptation.

Don J
2013-Sep-18, 07:19 PM
All the 'right' building blocks .. all the 'right' clays ... all the 'right' conditions ... but not a single hint of RNA on Mars ... and yet, 'life arises easily when liquid water and carbon-based compounds and an energy source are present', eh(?)
:confused:
That is not surprising if you consider that Mars have lost all of its water and atmosphere hundred millions or even 1 billion years ago and is now covered on its surface by a layer of perchlorates...I wondering if Earth was submitted to the same condition than Mars if RNA and DNA would be easely find as you suppose?
http://www.sciencemag.org/content/340/6129/138.2.summary
We have a long discussion in the recent past about the effect of perchlorate on the instruments analysis and also the MTBSTFA problem that the SAM instrument on bord of Curiosity is facing.:
http://cosmoquest.org/forum/showthread.php?143405-Mars-Soil-Resembles-Veggie-Garden-Dirt-Lander-Finds/page7

Selfsim
2013-Sep-19, 03:30 AM
That is not surprising if you consider that Mars have lost all of its water and atmosphere hundred millions or even 1 billion years ago and is now covered on its surface by a layer of perchlorates...I wondering if Earth was submitted to the same condition than Mars if RNA and DNA would be easely find as you suppose?Ahh .. that RNA/DNA is resilient stuff! It should be there .. an adapted extremophile .. and multiplying as well, no?


We have a long discussion in the recent past about the effect of perchlorate on the instruments analysis and also the MTBSTFA problem that the SAM instrument on bord of Curiosity is facing.:Sure. And where are the Cumberland SAM results, eh?

Selfsim
2013-Sep-19, 03:36 AM
I emailed the author, and she replied thusly: Good on you! Good on her for responding!

What's this
the first life probably arose around 3.5 billion years ago,?? 2.5 Gya is what we have by way of evidence.


I understand where she is coming from, but life being found in even inhospitable zones isnt abiogeneis, its adaptation.So why can't we find it easily on Mars? All this incident radiation and perchlorate stuff is trivial for an such an adaptable phenomena, no?

Are we to believe that it was 'easy' on Earth .. but not easy on Mars? (Bu tno .. its easy wherever the conditions she mentions are found ..) So what are the mechanisms which result in such frailty on Mars, especially seeing that we have no such evidence of fragility on Earth?

Don J
2013-Sep-19, 03:55 AM
Ahh .. that RNA/DNA is resilient stuff! It should be there .. an adapted extremophile .. and multiplying as well, no?

Hmm!That remind me of discussions about Levin and the Viking mission.
http://cosmoquest.org/forum/showthread.php?143405-Mars-Soil-Resembles-Veggie-Garden-Dirt-Lander-Finds/page6
post #158
http://cosmoquest.org/forum/showthread.php?143405-Mars-Soil-Resembles-Veggie-Garden-Dirt-Lander-Finds&p=2131630#post2131630
post #166
http://cosmoquest.org/forum/showthread.php?143405-Mars-Soil-Resembles-Veggie-Garden-Dirt-Lander-Finds&p=2131734#post2131734


Sure. And where are the Cumberland SAM results, eh?
You should ask the Curiosity mission leader about that.

Selfsim
2013-Sep-19, 04:15 AM
Hmm!That remind me of discussions about Levin and the Viking mission. .. post #158, post #166And what an enjoyable thread it was, too! :)
Oh those pesky Martian microbes developed natural sunscreens from "aromatic molecules conjugated with carbonyl groups" (http://en.wikipedia.org/wiki/Sunscreen#Active_ingredients).


You should ask the Curiosity mission leader for that.Well, why not all those roving 'cub' reporters .. like those who work for UT?

Don J
2013-Sep-19, 04:46 AM
And what an enjoyable thread it was, too! :)

Ditto! :)


Oh those pesky Martian microbes developed natural sunscreens from "aromatic molecules conjugated with carbonyl groups" (http://en.wikipedia.org/wiki/Sunscreen#Active_ingredients).

2.5 cm and more under the Martian soil is a good UV shield for the surviving microorganisms.


Well, why not all those roving 'cub' reporters .. like those who work for UT?
Effectively.

Selfsim
2013-Sep-19, 07:15 AM
So enough of that "be nice" stuff, let's get down to business ..

So, we have (Urry's posits):
i) "Life arises easily wherever there is liquid water (even in the interstices between ice crystals) and an energy source" and, (presumably) wherever environments like those created in the Miller-Urey experiments arise(?) (The second of these may not be essential).

Now, we know from empirical evidence:
ii) that life adapts to a changing environment and becomes abundant (Earth's evidence) and;
iii) that adundant life (or its signs) is not visibly present on the surface of Mars.

The hypothesis is:
iv) "Because of high UV and perchlorates on Mars' surface, maybe life, (or evidence for it), which is predicted to have 'arisen easily' on Mars, (because we have evidence that it had the right conditions in the past), has gone sub-surface(?)" This of course, is a reasoned, testable hypothesis.

However from the empirical evidence, (ii) and (iii) are most certainly valid. So, if we review posit (i) as well as hypothesis (iv) in the light of that evidence, perhaps we can also conclude that: "Maybe there never was any life on Mars(?)", and both posit (i) and reasoned testable hypothesis (iv), are both a false posit and an unsupported hypotheses, respectively(?) Now, I cannot test/verify this new conclusion/hypothesis on Mars .. it can be falsifed .. but I think its still logically (and equally) just as valid as (iv)(?)

I think the above process is valid .. mathematicians review their posits, (via mathematical induction - a form of deduction), all the time ... as a 'sanity check'.

So, I say the reason Mars is being explored, is to falsify my logically formed conclusion/hypothesis that:
"Maybe there never was any life on Mars and posit (i), and hypothesis (iv), were (maybe) simply never supported by the available evidence"(?)
Now, has my impeccable logic let me down yet again, and led me to yet another false conclusion/hypothesis? :confused: :p

iquestor
2013-Sep-19, 10:40 AM
iii) that adundant life (or its signs) is not visibly present on the surface of Mars.

Have we really tested this enough? Gorden-Levy controlled release experiment is still being discussed; Gordon maintains his results from Viking detected life. I know thats been discussed around here somewhere.

edit: of course, I wouldn't call what he feels he detected as "abundant life."


?? 2.5 Gya is what we have by way of evidence.

I remember reading there has been indirect but compelling evidence of life 3.5GYA . here (http://paleobiology.si.edu/geotime/main/htmlversion/archean3.html)

Selfsim
2013-Sep-19, 08:44 PM
Have we really tested this enough? Gorden-Levy controlled release experiment is still being discussed; Gordon maintains his results from Viking detected life. I know thats been discussed around here somewhere.

edit: of course, I wouldn't call what he feels he detected as "abundant life."I think you might mean the Gilbert Levin LR experiment ...


I remember reading there has been indirect but compelling evidence of life 3.5GYA . here (http://paleobiology.si.edu/geotime/main/htmlversion/archean3.html)From the article ..
At present, we can say with certainty that life had evolved by 2.7 billion years ago .. Anything else is just speculation .. and it serves to shorten the timeframe for evolution of life by ~1 Gya, (~20% of Earth's age), thus making it a self-fulfilling prophecy that 'life arises easily'.

"Just the facts, maam please" ..

iquestor
2013-Sep-20, 12:29 AM
I think you might mean the Gilbert Levin LR experiment ...

From the article .. Anything else is just speculation .. and it serves to shorten the timeframe for evolution of life by ~1 Gya, (~20% of Earth's age), thus making it a self-fulfilling prophecy that 'life arises easily'.

"Just the facts, maam … please" ..

yes I meant Gilbert Levin. Mustuv been tthinking of Shoemaker - Levy :)

Ive seen the 3.5 GYA in several references, that was a quick one I googled, not the one I was looking for. In *, A Short history of Nearly Everything the value 3.5GYA is used in several places (first on pp 298);

Don J
2013-Sep-20, 01:21 AM
So enough of that "be nice" stuff, let's get down to business ..

So, we have (Urry's posits):
i) "Life arises easily wherever there is liquid water (even in the interstices between ice crystals) and an energy source" and, (presumably) wherever environments like those created in the Miller-Urey experiments arise(?) (The second of these may not be essential).

Now, we know from empirical evidence:
ii) that life adapts to a changing environment and becomes abundant (Earth's evidence) and;
iii) that adundant life (or its signs) is not visibly present on the surface of Mars.

The current theory supported by Nasa or even Levin is that life on Mars have probably not developed further than microbes.
So saying that life on Mars -should have been- as abundant and diversified than on Earth sound like you are building a strawman to win an argument.

Selfsim
2013-Sep-20, 01:56 AM
The current theory supported by Nasa or even Levin is that life on Mars have probably not developed further than microbes.
So saying that life on Mars -should have been- as abundant and diversified than on Earth sound like you are building a strawman to win an argument.And yet "life arises easily" isn't another one, eh? :p :)

Don J
2013-Sep-20, 06:25 AM
And yet "life arises easily" isn't another one, eh? :p :)
She (Meg Urry) probably mean that "life arise easely" given the right condition(s) and time as it was the case on Earth.As she points out in post #17, Btw.


So, we have (Urry's posits):
i) "Life arises easily wherever there is liquid water (even in the interstices between ice crystals) and an energy source"


I have serious doubt about that possibility.It is rather probable that living microorganisms were already present in the water which have find a way through the interstices between ice crystals.The trapped microorganisms have adapted to the new environment.

And as pointed out by Inquestor in post 17:


Originally Posted by iquestor
I understand where she is coming from, but life being found in even inhospitable zones isnt abiogeneis, its adaptation.

Selfsim
2013-Sep-20, 07:26 AM
See, my point is that we know terrestrial life is adaptable, resilient and abundant.
From Earth's fossil evidence, Miller Urey, etc she infers that 'life arises easily'.
We know there is no abundant surface life on Mars, and yet it was supposedly a hospitable environment for life .. it should be abundant, and it should have been resilient and it should have adapted to whatever environment came up there, (because of the first statement above).
So, why no visible abundant life on the surface of Mars? (It should also have 'arisen easily', no?)

Rather than revising the inference that life, (when it arises), 'arises easily' (which we basically don't know, because we have no observations of its emergence, or any ideas about the sensitivities of the process), a 'story' is developed about sub-surface life on Mars, in order to preserve the initial inference based hypothesis (which is Ok) .. but just as valid, (even moreso, perhaps), is that the inference is not supported by direct observations thus far, on the surface of Mars ... so maybe 'life doesn't arise easily', after all(?)

Its the logic of the argument which I'm querying here ... I've heard all the 'stories' for why it might not be in abundance on the surface of Mars ... and these are not as simple as a simple revision of the initial hypothetical posit, especially in the light of there not being abundant, adapted, resilient surface life on Mars(?)

The end result is that we still don't know that: "life arises easily, wherever (etc, etc)" ...

Paul Wally
2013-Sep-20, 10:32 AM
See, my point is that we know terrestrial life is adaptable, resilient and abundant.
From Earth's fossil evidence, Miller Urey, etc she infers that 'life arises easily'.
We know there is no abundant surface life on Mars, and yet it was supposedly a hospitable environment for life .. it should be abundant, and it should have been resilient and it should have adapted to whatever environment came up there, (because of the first statement above).
So, why no visible abundant life on the surface of Mars? (It should also have 'arisen easily', no?)



No, why should we expect abundant life on the surface of Mars, if life arises easily? Mars is drier and colder than the driest and coldest places on Earth. Why should we expect to see 'visible abundant life" on Mars, when we don't even see such abundance in the driest places on Earth?

Selfsim
2013-Sep-20, 11:14 AM
No, why should we expect abundant life on the surface of Mars, if life arises easily? Mars is drier and colder than the driest and coldest places on Earth. Why should we expect to see 'visible abundant life" on Mars, when we don't even see such abundance in the driest places on Earth?Well, maybe because 'drier and colder' is the predominant environment on Mars ... which changed from a predominant environment of a much 'wetter and warmer' one, where life 'should have' arisen there. If life did arise in the latter environment on Mars, then it would be expected to have evolved subsequently (and commensurately) with that environment, as it got drier and colder, no(?)

Either life is adpatable with the environment it finds itself 'emerging' in, or it isn't, no?

The Atacama lifeforms are regarded as 'extremophiles' from amongst the bulk of terrestrial life. I don't think comparing a terrestrial extremophile environment on Earth, with a run-of-the-mill environment on Mars, is an apples-to-apples comparison .. so why would one expect the lifeforms in a run-of-the-mill environment on Mars, to exhibit the same scarcity as an extremophile population on Earth(?)

iquestor
2013-Sep-20, 11:27 AM
Could we take current terrestrial extremophiles from similar places on Earth, let them adapt if possible to conditions on Mar's surface, and then see if they thrive?

Of course, this doesn't say anything about abiogenesis on Mars. but it would show that organisms could adapt to the current condition on Mars, if they were ever there at all.

Paul Wally
2013-Sep-20, 04:58 PM
Well, maybe because 'drier and colder' is the predominant environment on Mars ... which changed from a predominant environment of a much 'wetter and warmer' one, where life 'should have' arisen there. If life did arise in the latter environment on Mars, then it would be expected to have evolved subsequently (and commensurately) with that environment, as it got drier and colder, no(?)

Yes, but irrespective of what the predominant environment is, any given life has certain physical requirements like a liquid solvent for instance. Not even evolution can get around such constraints. This is evident from the fact that life flourishes in certain environments and not in others. What this shows that an environment can physically change in ways that are either conducive or not conducive to the existence of life. In the case of Mars it is entirely possible that surface life could have emerged easily in warmer and wetter conditions and then became extinct as a result of changes in the physical conditions.


Either life is adpatable with the environment it finds itself 'emerging' in, or it isn't, no?

Yes, life is adaptable, but within the limits of physical possibility and probability.



The Atacama lifeforms are regarded as 'extremophiles' from amongst the bulk of terrestrial life. I don't think comparing a terrestrial extremophile environment on Earth, with a run-of-the-mill environment on Mars, is an apples-to-apples comparison .. so why would one expect the lifeforms in a run-of-the-mill environment on Mars, to exhibit the same scarcity as an extremophile population on Earth(?)

What the Atacama desert, Antarctica and other deserts on Earth illustrate is that it is possible for a physical environment to change in ways that are less conducive to 'visible abundant life'.

Selfsim
2013-Sep-20, 10:34 PM
Yes, but irrespective of what the predominant environment is, any given life has certain physical requirements like a liquid solvent for instance. Not even evolution can get around such constraints. This is evident from the fact that life flourishes in certain environments and not in others. What this shows that an environment can physically change in ways that are either conducive or not conducive to the existence of life. In the case of Mars it is entirely possible that surface life could have emerged easily in warmer and wetter conditions and then became extinct as a result of changes in the physical conditions.Yes, I suppose ..

Its an interesting question .. can adaptable life find a way to 'flourish' even when conditions change to a colder, drier one (over millions of years)?
Also, if it seems it cannot, (from Earth's extremophile case evidence), then why can't the abiogenesis process not be perturbed in the same same way, so as to result in 'no life'?

Coming back to the basis of logic of the argument, I notice I'm now arguing from Earth's extremophile evidence basis, (as it applies to abiogenesis) .. as opposed to the 'run-of-the-mill case. (Which is the opposite of what I was arguing before). :)
(Declared purely in the interest of saving discussion time, I might add).

Perhaps a condition-sensitive abiogenesis process, which runs over billions of years, can also act so as to inhibit the development of life from inorganically based complex processes(?) One of Pross' DKS attractor 'states' (admittedly my terminology here), could just as easily be a 'no life' one .. just as a river can easily run dry, so too maybe abiogenesis can 'run dry' half-way through(?) .. (Sorry Mr Kauffman .. it can work both ways ..logically speaking, that is).


Yes, life is adaptable, but within the limits of physical possibility and probability.Then so too would abiogenesis be subject to the same conditions and perhaps the same sensitivities, no? (Logically speaking, that is .. given we "don't know" about abiogenesis, that is).


What the Atacama desert, Antarctica and other deserts on Earth illustrate is that it is possible for a physical environment to change in ways that are less conducive to 'visible abundant life'.See above points.

I guess the main point here, (for this thread), is that a purely logical argument basis, leads to the possibility of both ends of the spectrum .. ie: it sucks up either Earth's extremophile or Earth's run-of-the-mill evidence, and doesn't advance thinking beyond that evidence .. and the evidence is still insufficient to draw conclusions from. Logic doesn't further either perspective

We simply, "don't know that life arises easily, (whenever, wherever etc, etc)"

Don J
2013-Sep-20, 11:19 PM
Yes, I suppose ..

Its an interesting question .. can adaptable life find a way to 'flourish' even when conditions change to a colder, drier one (over millions of years)?
Also, if it seems it cannot, (from Earth's extremophile case evidence), then why can't the abiogenesis process not be perturbed in the same same way, so as to result in 'no life'?

Because Earth have still a thick atmosphere acting as a UV filter which reduce the destructive effect of the UV on living things of about 90 percent.As you surely know,Mars have lost about all of its atmosphere so the UV are at such a level on the Mars surface than it make microorganisms survival and adaptation(extremophile) on its surface very unlikely.However that does not exclude the possibility that some scarce population of living microorganisms still exist 2,5 cm and more under the Martian soil where they are protected from the destructive action of the UV.

Selfsim
2013-Sep-20, 11:40 PM
Because Earth have still a thick atmosphere acting as a UV filter which reduce the destructive effect of the UV on living things of about 90 percent.As you surely know,Mars have lost about all of its atmosphere so the UV are at such a level on the Mars surface than it make microorganisms survival and adaptation(extremophile) on its surface very unlikely.However that does not exclude the possibility that some scarce population of living microorganisms still exist 2,5 cm and more under the Martian soil where they are protected from the destructive action of the UV.There are quite a few creatures which have developed highly effective UV absorbing sunscreens (ie: mucus), in order to survive in their ambient UV environments.

Why wouldn't a martian lifeform be able to do this in its environment?
(Or at least develop the stuff to the point of being able to hang out for periods on the beach rocks, in order to socialise with their surfing buddies, in the past? .. Now I'm sure you could come up with an answer to this question .. but that would be just another story to perpetuate the original posit of: "sub-surface life exists".. and that's the point I'm making, here).

Don J
2013-Sep-21, 01:24 AM
There are quite a few creatures which have developed highly effective UV absorbing sunscreens (ie: mucus), in order to survive in their ambient UV environments.

The important point is that their ambient UV environments -on Earth- is filtered at 90 percent from the nocive effect of UV by the thickness of the Earth atmosphere.


Why wouldn't a martian lifeform be able to do this in its environment?

You should know why by now.... What would have happened to life on the surface of the Earth if the Earth have lost -about all of its atmosphere - and all its surface water about 1 billion years ago like Mars?

MaDeR
2013-Sep-25, 05:42 PM
Man, there is some serious strawman building in this thread. Claiming "life arises easily" = "flourishing surface biosphere on Mars" was particularly funny.