Happy Atheist Forum

General => Science => Topic started by: Icarus on December 13, 2014, 11:41:28 PM

Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Icarus on December 13, 2014, 11:41:28 PM
Ken Hamm ain't gonna' like this
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on October 22, 2015, 07:28:42 AM
Well, at least we have one post from this thread, so I'll add to it, as a token of my belief that the rest of the posts will be restored by our splendid Grey Adminence.  :asmo:

* * *

Some very interesting evidence has been found which may be an indication that life began considerably earlier than previously thought.

"Life on Earth likely started 4.1 billion years ago, much earlier than scientists thought" | Geology Page (http://www.geologypage.com/2015/10/life-on-earth-likely-started-41-billion.html)

QuoteUCLA geochemists have found evidence that life likely existed on Earth at least 4.1 billion years ago -- 300 million years earlier than previous research suggested. The discovery indicates that life may have begun shortly after the planet formed 4.54 billion years ago.

The research is published today in the online early edition of the journal Proceedings of the National Academy of Sciences.

"Twenty years ago, this would have been heretical; finding evidence of life 3.8 billion years ago was shocking," said Mark Harrison, co-author of the research and a professor of geochemistry at UCLA.

. . .

The researchers, led by Elizabeth Bell -- a postdoctoral scholar in [Mark] Harrison's laboratory -- studied more than 10,000 zircons originally formed from molten rocks, or magmas, from Western Australia. Zircons are heavy, durable minerals related to the synthetic cubic zirconium used for imitation diamonds. They capture and preserve their immediate environment, meaning they can serve as time capsules.

The scientists identified 656 zircons containing dark specks that could be revealing and closely analyzed 79 of them with Raman spectroscopy, a technique that shows the molecular and chemical structure of ancient microorganisms in three dimensions.

Bell and [Patrick] Boehnke, who have pioneered chemical and mineralogical tests to determine the condition of ancient zircons, were searching for carbon, the key component for life.

One of the 79 zircons contained graphite -- pure carbon -- in two locations.

"The first time that the graphite ever got exposed in the last 4.1 billion years is when Beth Ann and Patrick made the measurements this year," Harrison said.

[Continues . . . (http://www.geologypage.com/2015/10/life-on-earth-likely-started-41-billion.html)]

The full paper is available as well. "Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon" | Proceedings of the National Academy of Sciences (PDF) (http://www.pnas.org/content/early/2015/10/14/1517557112.full.pdf)
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on November 16, 2015, 08:13:17 PM
I don't recall whether these particular resources were linked in the original full thread, but they belong here:

Abiogenesis & Evolution (http://abiogenesisevo.blogspot.com/)

The Origins of Life: Cold Spring Harbor Perspectives in Biology (http://cshperspectives.cshlp.org/site/misc/the_origins_of_life.xhtml)

RNA Worlds: Cold Spring Harbor Perspectives in Biology (http://cshperspectives.cshlp.org/site/misc/rna_worlds.xhtml)

Exploring Life's Origins (http://exploringorigins.org/index.html)

YouTube videos of lecture by Jack Szostak: "The Origin of Life on Earth" (https://www.youtube.com/watch?v=PqPGOhXoprU&list=PLIotpBG-g_3kU_e0MH6Z6hXJOpD1lzvGr)

Abiogenesis & Evolution (http://abiogenesisevo.blogspot.com/)



Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on April 25, 2016, 11:37:36 PM
More that Ken Ham and other Creationist science deniers won't like.

"Missing links brewed in primordial puddles?" | ScienceDaily (https://www.sciencedaily.com/releases/2016/04/160425095115.htm)

QuoteThe crucibles that bore out early building blocks of life may have been, in many cases, modest puddles.

Now, researchers working with that hypothesis have achieved a significant advancement toward understanding an evolutionary mystery -- how components of RNA and DNA formed from chemicals present on early Earth before life existed.

In surprisingly simple laboratory reactions in water, under everyday conditions, they have produced what could be good candidates for missing links on the pathway to the code of life.

And when those components joined up, the result even looked like RNA.

As the researchers' work progresses, it could reveal that much of the original chemistry that led to life arose not in fiery cataclysms and in scarce quantities, but abundantly and gradually on quiet, rain-swept dirt flats or lakeshore rocks lapped by waves.

[Continues . . . (https://www.sciencedaily.com/releases/2016/04/160425095115.htm)]

The full paper ("Spontaneous formation and base pairing of plausible prebiotic nucleotides in water" (http://www.nature.com/ncomms/2016/160425/ncomms11328/full/ncomms11328.html)) is available for free from Nature.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Icarus on April 26, 2016, 01:09:59 AM
Thank you the links Rec. Sad to say that our fundie friends will not place much stock in such heady stuff.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Tank on April 26, 2016, 06:29:22 AM
Very interesting.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on September 22, 2017, 04:36:45 PM
The pop-science headlines about the paper described below overstate things per usual (as does the linked article itself). Some of the statements of its authors are also unsupportable in the context of their findings. Nonetheless, it does appear to be a breakthrough in learning about a plausible scenario for the beginning of life here on Earth.

"Complex life evolved out of the chance coupling of small molecules" | PhysOrg (https://phys.org/news/2017-09-complex-life-evolved-chance-coupling.html)

QuoteComplex life, as we know it, started completely by chance, with small strands of molecules linking up, which eventually would have given them the ability to replicate themselves.

In this world, billions of years ago, nothing existed that we would recognise today as living. The world contained only lifeless molecules that formed spontaneously through the natural chemical and physical processes on Earth.

However, the moment that small molecules connected and formed larger molecules with the ability to replicate themselves, life started to evolve.

"Life was a chance event, there is no doubt about that," says Dr Pierre Durand from the Evolution of Complexity Laboratory in the Evolutionary Studies Institute at Wits University, who led a project to find out how exactly these molecules linked up with each other. Their results are published today in the journal Royal Society Open Science, in a paper entitled "Molecular trade-offs in RNA ligases affected the modular emergence of complex ribozymes at the origin of life".

Very simple ribonucleic acid (RNA) molecules (compounds similar to Deoxyribonucleic acid(DNA)) can join other RNA molecules to themselves though a chemical reaction called ligation. The random joining together of different pieces or RNA could give rise to a group of molecules able to produce copies of themselves and so kick start the process of life.

While the process that eventually led to the evolution of life took place over a long period of time, and involved a number of steps, Wits PhD student Nisha Dhar and Durand have uncovered how one of these crucial steps may have occurred.

They have demonstrated how small non-living molecules may have given rise to larger molecules that were capable of reproducing themselves. This path to self-replicating molecules was a key event for life to take hold.

"Something needed to happen for these small molecules to interact and form longer, more complex molecules and that happened completely by chance," says Durand.

[Continues . . . (https://phys.org/news/2017-09-complex-life-evolved-chance-coupling.html#jCp)]

The conclusions of the paper (available for free here (http://rsos.royalsocietypublishing.org/content/4/9/170376)) are less sensationalized and make the actual findings fairly clear:

QuoteLigases (and related polymerases) have primarily been explored with the aim of evolving a self-replicating enzyme. However, while these self-replicating ribozymes are key components of a replicating RNA world, an explanation is needed for the emergence of such molecules that are much larger in size than those that formed spontaneously in the prebiotic world.

This study reveals how the activity of small ligases could have led to larger, more complex molecules. The ligases exhibited differential functional flexibility and efficiency which correlated with their size and stability. The results indicate that, in the early stages of the RNA world, molecular size could have increased in a modular, stepwise fashion via the reactions of small ligases with a range of oligomers, albeit with a relatively poor efficiency. It supports the computational and theoretical predictions that assembly of larger functional molecules resulted from short RNA ligases. The derived larger and more complex ligases developed specificity and efficiency for the kinds of substrates ligated. This trade-off could have contributed to building molecular complexity and the generation of a pool of functionally specialized molecules, which were necessary for the emergence of a self-sustained replicating system.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on May 31, 2018, 06:42:09 PM
Ongoing research into possible origins of life on Earth continues to produce results. Not surprisingly, these results could not only enlarge our knowledge but provide practical benefit.

"Scientists crack how primordial life on Earth might have replicated itself" | ScienceDaily (https://www.sciencedaily.com/releases/2018/05/180515131551.htm)

QuoteScientists have created a new type of genetic replication system which demonstrates how the first life on Earth -- in the form of RNA -- could have replicated itself. The scientists say the new RNA utilizes a system of genetic replication unlike any known to naturally occur on Earth today.

A popular theory for the earliest stages of life on Earth is that it was founded on strands of RNA, a chemical cousin of DNA. Like DNA, RNA strands can carry genetic information using a code of four molecular letters (bases), but RNA can be more than a simple 'string' of information. Some RNA strands can also fold up into three-dimensional shapes that can form enzymes, called ribozymes, and carry out chemical reactions.

If a ribozyme could replicate folded RNA, it might be able to copy itself and support a simple living system.

Previously, scientists had developed ribozymes that could replicate straight strands of RNA, but if the RNA was folded it blocked the ribozyme from copying it. Since ribozymes themselves are folded RNAs, their own replication is blocked.

Now, in a paper published today in the journal eLife, the scientists have resolved this paradox by engineering the first ribozyme that is able to replicate folded RNAs, including itself.

[. . .]

Dr Nathan Richardson, Head of Molecular and Cellular Medicine at the MRC, said: "This is a really exciting example of blue skies research that has revealed important insights into how the very beginnings of life may have emerged from the 'primordial soup' some 3.7 billion years ago. Not only is this fascinating science, but understanding the minimal requirements for RNA replication and how these systems can be manipulated could offer exciting new strategies for treating human disease."

[Link to full article. (https://www.sciencedaily.com/releases/2018/05/180515131551.htm)]



Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Dave on May 31, 2018, 07:56:17 PM
Oh, dear, another thing for Prince  Charlie to worry about! He is already concerned that nano-particles will turn the sea into a lifeless soup. If this stuff escapes it may turn it into a lifeless (for a few millions years in terms of anything  like a uni-cellular system) gloupy soup!
Title: Re: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: No one on May 31, 2018, 10:13:27 PM
So, it wasn't a wave of a magic wand?
Title: Re: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Arturo on May 31, 2018, 11:51:50 PM
Quote from: No one on May 31, 2018, 10:13:27 PM
So, it wasn't a wave of a magic wand?

Nah. This is how it happened.

Sorry but you are not allowed to view spoiler contents.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Icarus on June 02, 2018, 07:04:24 AM
Prince Charlie may be onto something. The May edition of Scientific American has a rather interesting article about deep sea mining.  There are minerals on the bottom of the ocean that have been accumulating in useful quantities for a million years or so.  Those minerals, metals actually, are thousands of feet below the surface.  The process of extraction involves  dredging and also scraping of undersea rock formations.

The problem is that such displacement of the natural environment is likely to influence, even destroy, some of the animal and bacterial life that helps keep the ocean "clean".  Nickle, Cobalt and copper are some of the deposits that are being depleted on terra firma.  There is ample deposit of those metals far down in the briny deep. Mining them may cause a great deal of distress to the ocean and its' inhabitants.

See International Seabed  authority ....www.isa.org.jm   or the Scripps Institute of Oceanography at.. www.mod.uscd.edu/plumex
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Dave on June 02, 2018, 08:38:19 AM
Quote from: Icarus on June 02, 2018, 07:04:24 AM
Prince Charlie may be onto something. The May edition of Scientific American has a rather interesting article about deep sea mining.  There are minerals on the bottom of the ocean that have been accumulating in useful quantities for a million years or so.  Those minerals, metals actually, are thousands of feet below the surface.  The process of extraction involves  dredging and also scraping of undersea rock formations.

The problem is that such displacement of the natural environment is likely to influence, even destroy, some of the animal and bacterial life that helps keep the ocean "clean".  Nickle, Cobalt and copper are some of the deposits that are being depleted on terra firma.  There is ample deposit of those metals far down in the briny deep. Mining them may cause a great deal of distress to the ocean and its' inhabitants.

See International Seabed  authority ....www.isa.org.jm   or the Scripps Institute of Oceanography at.. www.mod.uscd.edu/plumex

One of the big problems there is the effects on methane hydrates, stable at grest depth but unstable enough if didturbed to create a global warming problem. Once I thought the problem was from the mechanical disturbance of seabed mining only - but it seems that global warming has the same effect.
https://worldoceanreview.com/en/wor-1/ocean-chemistry/climate-change-and-methane-hydrates/

But, that's getting way OT and Charlie was/is concerned about polution effects. If the sort of self-replicating material in the wrticle escapes it could possibly multiply and spread.

Further on Charlie's fears if the microfibres from washed artificial fabrics + nano-particles from skin creams etc + plastic micro/nano-particles + . . . all add up - oops.

Also OT: there was a docu on TV where they were setting ponds alight in the Russian tundra. The bubbles under the ice were not air but methsne released due to global warming. Impressive gouts of flame but quite worrying positive feedback - like that of the hydrates.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Icarus on June 03, 2018, 05:30:29 AM
Malthus was almost right.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Dave on June 28, 2018, 09:18:21 PM
On the edge of this is complex organics veing found elsewhere:
QuoteA new look at old data from NASA's Cassini orbiter shows complex organic molecules are gushing from the tiny moon [Enceladus]

Complex organic molecules have been discovered for the first time coming from the depths of Saturn's moon Enceladus, a new study reported.

Spacecraft scheduled to launch soon could explore what this new discovery says about the chances of life within icy moons like Enceladus, the study's researchers said.

The sixth largest of Saturn's moons, Enceladus is only about 314 miles (505 kilometers) in diameter. This makes the moon small enough to fit inside the borders of Arizona.
https://www.scientificamerican.com/article/ingredients-for-life-found-on-saturns-moon-enceladus/
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on September 14, 2018, 08:50:05 PM
The sword ("it's just a theory!") and shield ("were you there?") of Creationism will stand those who wield them in good stead when it comes to dealing with this. It's merely a computer model, and all that's being claimed is that a particular peptide may have been part of the formation of life on Earth. No matter--knowledge continues to advance.

"Scientists identify protein that may have existed when life began" | ScienceDaily (https://www.sciencedaily.com/releases/2018/08/180830180101.htm)

QuoteHow did life arise on Earth? Rutgers researchers have found among the first and perhaps only hard evidence that simple protein catalysts -- essential for cells, the building blocks of life, to function -- may have existed when life began.

Their study of a primordial peptide, or short protein, is published in the Journal of the American Chemical Society.

In the late 1980s and early 1990s, the chemist Günter Wächtershäuser postulated that life began on iron- and sulfur-containing rocks in the ocean. Wächtershäuser and others predicted that short peptides would have bound metals and served as catalysts of life-producing chemistry, according to study co-author Vikas Nanda, an associate professor at Rutgers' Robert Wood Johnson Medical School.

Human DNA consists of genes that code for proteins that are a few hundred to a few thousand amino acids long. These complex proteins -- needed to make all living-things function properly -- are the result of billions of years of evolution. When life began, proteins were likely much simpler, perhaps just 10 to 20 amino acids long. With computer modeling, Rutgers scientists have been exploring what early peptides may have looked like and their possible chemical functions, according to Nanda.

[Continues . . . (https://www.sciencedaily.com/releases/2018/08/180830180101.htm)]
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on October 21, 2018, 05:50:54 PM
"But you weren't there!"

"Chemists find a recipe that may have jump-started life on Earth" | Science (https://www.sciencemag.org/news/2018/10/chemists-find-recipe-may-have-jump-started-life-earth?)

QuoteIn the molecular dance that gave birth to life on Earth, RNA appears to be a central player. But the origins of the molecule, which can store genetic information as DNA does and speed chemical reactions as proteins do, remain a mystery. Now, a team of researchers has shown for the first time that a set of simple starting materials, which were likely present on early Earth, can produce all four of RNA's chemical building blocks.

Those building blocks—cytosine, uracil, adenine, and guanine—have previously been re-created in the lab from other starting materials. In 2009, chemists led by John Sutherland at the University of Cambridge in the United Kingdom devised a set of five compounds likely present on early Earth that could give rise to cytosine and uracil (http://www.sciencemag.org/news/2015/03/researchers-may-have-solved-origin-life-conundrum), collectively known as pyrimidines. Then, 2 years ago, researchers led by Thomas Carell, a chemist at Ludwig Maximilian University in Munich, Germany, reported that his team had an equally easy way to form adenine and guanine (http://www.sciencemag.org/news/2016/05/rna-world-inches-closer-explaining-origins-life), the building blocks known as purines. But the two sets of chemical reactions were different. No one knew how the conditions for making both pairs of building blocks could have occurred in the same place at the same time.

Now, Carell says he may have the answer. On Tuesday, at the Origins of Life Workshop here, he reported that he and his colleagues have come up with a simple set of reactions that could have given rise to all four RNA bases.

[Continues . . . (https://www.sciencemag.org/news/2018/10/chemists-find-recipe-may-have-jump-started-life-earth?)]
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Tank on October 21, 2018, 06:37:20 PM
Interesting as usual.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on February 12, 2019, 09:12:14 PM
Further research on the possible routes by which life first formed.

"Membraneless protocells could provide clues to formation of early life" | ScienceDaily (https://www.sciencedaily.com/releases/2019/01/190131125954.htm)

QuoteMembraneless assemblies of positively- and negatively-charged molecules can bring together RNA molecules in dense liquid droplets, allowing the RNAs to participate in fundamental chemical reactions. These assemblies, called "complex coacervates," also enhance the ability of some RNA molecules themselves to act as enzymes -- molecules that drive chemical reactions. They do this by concentrating the RNA enzymes, their substrates, and other molecules required for the reaction. The results of testing and observation of these coacervates provide clues to reconstructing some of the early steps required for the origin of life on Earth in what is referred to as the prebiotic "RNA world." A paper describing the research, by scientists at Penn State, appears January 30, 2019 in the journal Nature Communications.

"We're interested in how you go from a world with no life to one with life," said Philip C. Bevilacqua, Distinguished Professor of Chemistry and of Biochemistry and Molecular Biology at Penn State and one of the senior authors of the paper. "One can imagine a lot of steps in this process, but we are not looking at the most elemental steps. We are interested in a slightly later step, to see how RNA molecules could form from their basic building blocks and if those RNA molecules could drive the reactions needed for life in the absence of proteins."

[. . .]

"It was previously known that RNA molecules can assemble and elongate in solutions with high concentrations of magnesium," said Poudyal. "Our work shows that coacervates made from certain materials allow this non-enzymatic template-mediated RNA assembly to occur even in the absence of magnesium."

The coacervates are composed of positively charged molecules called polyamines and negatively charged polymers which cluster together to form membraneless compartments in a solution. Negatively charged RNA molecules are also attracted to the polyamines in the coacervates. Within the coacervates the RNA molecules are as much as 4000 times more concentrated than in the surrounding solution. By concentrating the RNA molecules in the coacervates, RNA enzymes are more likely to find their targets to drive chemical reactions.

[Continues. . . (https://www.sciencedaily.com/releases/2019/01/190131125954.htm)]

The full paper is available for free: "Template-directed RNA polymerization and enhanced ribozyme catalysis inside membraneless compartments formed by coacervates" | Nature Communications (https://www.nature.com/articles/s41467-019-08353-4)
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Essie Mae on February 13, 2019, 07:31:32 PM
That must have been an amazingly exciting moment.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on April 03, 2019, 02:48:26 AM
Maybe it was not just an RNA world (https://en.wikipedia.org/wiki/RNA_world).

"Building blocks of DNA and RNA could have appeared together before life began on Earth" | ScienceDaily (https://www.sciencedaily.com/releases/2019/04/190401171401.htm)


QuoteScientists for the first time have found strong evidence that RNA and DNA could have arisen from the same set of precursor molecules even before life evolved on Earth about four billion years ago.

The discovery, published April 1 in Nature Chemistry, suggests that the first living things on Earth may have used both RNA and DNA, as all cell-based life forms do now. In contrast, the prevailing scientific view -- the "RNA World" hypothesis -- is that early life forms were based purely on RNA, and only later evolved to make and use DNA.

"These new findings suggest that it may not be reasonable for chemists to be so heavily guided by the RNA World hypothesis in investigating the origins of life on Earth," says co-principal investigator Ramanarayanan Krishnamurthy, PhD, associate professor of chemistry at Scripps Research.

[. . .]

RNA (ribonucleic acid) and DNA (deoxyribonucleic acid) are chemically very similar, but chemists have never been able to show how the one could have been converted to the other on the early Earth, except with the help of enzymes produced by early organisms. Due in part to this lack of a demonstrated pre-life or "pre-biotic" chemical path connecting RNA to DNA, researchers in this field have been inclined to think that the simpler, more versatile one, RNA, was the basis for the first life forms -- or at least for an early stage of life prior to the emergence of DNA. RNA is able to store genetic information as DNA can, is able to catalyze biochemical reactions as protein enzymes can, and otherwise probably could have performed the basic biological tasks that would have been necessary in the first life forms.

Although origin-of-life researchers in recent decades have largely come to embrace the RNA World hypothesis, Sutherland, Krishnamurthy, Harvard's Jack Szostak and others have accumulated evidence that RNA and DNA may have arisen more or less all at once in the first life forms.

[Continues . . . (https://www.sciencedaily.com/releases/2019/04/190401171401.htm)]
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Ecurb Noselrub on April 03, 2019, 09:31:03 PM
It seems (to a layman like myself) like the cosmos has a self-organizing aspect as part of its fabric, so it's really not all that surprising that this level of organization should appear spontaneously. 
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on April 15, 2019, 05:08:39 AM
Why ponds might have been a more likely environment than oceans for the first appearance of life.

"Earliest life may have arisen in ponds, not oceans" | EurekAlert (https://www.eurekalert.org/pub_releases/2019-04/miot-elm041219.php)

QuotePrimitive ponds may have provided a suitable environment for brewing up Earth's first life forms, more so than oceans, a new MIT study finds.

Researchers report that shallow bodies of water, on the order of 10 centimeters deep, could have held high concentrations of what many scientists believe to be a key ingredient for jump-starting life on Earth: nitrogen.

In shallow ponds, nitrogen, in the form of nitrogenous oxides, would have had a good chance of accumulating enough to react with other compounds and give rise to the first living organisms. In much deeper oceans, nitrogen would have had a harder time establishing a significant, life-catalyzing presence, the researchers say.

"Our overall message is, if you think the origin of life required fixed nitrogen, as many people do, then it's tough to have the origin of life happen in the ocean," says lead author Sukrit Ranjan, a postdoc in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS). "It's much easier to have that happen in a pond."

[. . .]

[I]n this new study, he identifies two significant "sinks," or effects that could have destroyed a significant portion of nitrogenous oxides, particularly in the oceans. He and his colleagues looked through the scientific literature and found that nitrogenous oxides in water can be broken down via interactions with the sun's ultraviolet light, and also with dissolved iron sloughed off from primitive oceanic rocks.

Ranjan says both ultraviolet light and dissolved iron could have destroyed a significant portion of nitrogenous oxides in the ocean, sending the compounds back into the atmosphere as gaseous nitrogen.

"We showed that if you include these two new sinks that people hadn't thought about before, that suppresses the concentrations of nitrogenous oxides in the ocean by a factor of 1,000, relative to what people calculated before," Ranjan says.

[. . .]

The debate over whether life originated in ponds versus oceans is not quite resolved, but Ranjan says the new study provides one convincing piece of evidence for the former.

"This discipline is less like knocking over a row of dominos, and more like building a cathedral," Ranjan says. "There's no real 'aha' moment. It's more like building up patiently one observation after another, and the picture that's emerging is that overall, many prebiotic synthesis pathways seem to be chemically easier in ponds than oceans."

[Link to full article (https://www.eurekalert.org/pub_releases/2019-04/miot-elm041219.php)]

A cathedral? Oh, the arrogance, the sheer gall of these people!  :lol:
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Davin on April 15, 2019, 04:03:25 PM
Quote from: Recusant on April 15, 2019, 05:08:39 AM
A cathedral? Oh, the arrogance, the sheer gall of these people!  :lol:
(https://i.imgur.com/0zy7MhY.gif)

Good article.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on August 08, 2019, 07:53:50 PM
I think that this study may tie into some of the work that Jack Szostak's group has done. (A recent article about what Szostak has been up to--"How Life Began" | Harvard Magazine (https://harvardmagazine.com/2019/07/origin-life-earth)).

The Key to Life's Emergence? Bubbles, New Study Argues" | LiveScience (https://www.livescience.com/66105-bubbles-early-life.html)

QuoteBefore life on Earth emerged, by about 3.5 billion years ago, the oceans were a soup of randomly jumbled molecules. Then, somehow, some of those molecules arranged themselves into well-organized strings of DNA, protective cell walls, and tiny organ-like structures capable of keeping cells alive and functioning. But just how they accomplished this organization has long baffled scientists. Now, biophysicists at Ludwig–Maximilians University in Munich think they have an answer: bubbles.

[. . .]

Bubbles were everywhere in Earth's early seascape. Warm, deep-sea volcanoes spurted fizzy plumes. Those airy orbs, settled on the porous volcanic rock. These were the conditions that Braun and his colleagues sought to replicate. They created a vessel out of a porous material that mimicked the texture of volcanic rock, then filled it, in turn, with six different solutions, each modeling a different stage in the life-formation process. One solution, representing an early step, contained a sugar called RAO, which would have been necessary in the construction of nucleotides, the building blocks of RNA and DNA. Other solutions, representing the later stages, contained RNA itself, as well as the fats necessary to construct cell walls. [7 Theories on the Origin of Life (https://www.livescience.com/13363-7-theories-origin-life.html)]

Then, the researchers heated the solution on one end and cooled it on the other. They were creating something called a "thermal gradient," in which the temperature gradually changes from one end to another, similar to the way the water near deep-sea thermal vents gradually changes from hot to cold.

"It's like a micro-ocean," Braun said.

In each solution, the temperature change forces the molecules to clump — and they gravitated toward the bubbles that naturally form under these conditions. Almost immediately, they began reacting.

Sugars formed crystals, a kind of skeleton for RNA and DNA nucleotides. Acids formed longer chains, taking another step toward the formation of complex, RNA-like molecules. Finally, the molecules arranged themselves into structures that resembled simple cells. In a basic sense, Braun said, cells are molecules encased in bags made of fats. That's exactly what happened on the surface of his bubbles: Fats arranged themselves in spheres around the RNA and other molecules.

Most surprising to Braun and his colleagues, he said, was how rapidly these changes happened, in under 30 minutes.

"I was amazed," he said. Though this is the first time he and his colleagues have looked specifically at bubbles, the researchers have previously tried to replicate how these biological molecules undergo the complex reactions needed for life. Normally, he said, these reactions take hours.

Some chemists are skeptical, however, that Braun's bubbles are an accurate representation of the primordial environment. Braun and his colleagues seeded their solution with many of the complex molecules needed for life. Even their simplest solutions still represented later stages of the life-formation process, Ramanarayanan Krishnamurthy, a chemist at the Scripps Institution of Oceanography who was not involved in the study, told Live Science. That's a bit like baking a cake with a box mix, rather than starting from scratch.

In contrast, the ancient oceans may not have had the right conditions to form these initial molecules, Krishnamurthy said.

[Continues . . . (https://www.livescience.com/66105-bubbles-early-life.html)]
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Icarus on August 11, 2019, 10:06:32 PM
Those primitive ponds may have contained algae useful for food to nourish whatever life forms might have been in place.  Here is another twist on the usefulness of certain algae...................
https://massivesci.com/articles/iwi-algae-protein-nannochloropsis-food-essential-amino-acids/?utm_source=pocket-newtab
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on March 17, 2021, 08:34:32 PM
A new study supports the idea that lightning strikes likely helped provide the phosphorus necessary to the appearance of life on Earth.

"Origin of life: lightning strikes may have provided missing ingredient for Earth's first organisms" | The Conversation (https://theconversation.com/origin-of-life-lightning-strikes-may-have-provided-missing-ingredient-for-earths-first-organisms-157343)

QuoteThe origin of life on Earth is one of the most complex puzzles facing scientists. It involves not only identifying the numerous chemical reactions that must take place to create a replicating organism, but also finding realistic sources for the ingredients needed for each of the reactions.

One particular problem that has long faced scientists who study the origin of life is the source of the elusive element, phosphorus. Phosphorus is an important element for basic cell structures and functions. For example, it forms the backbone of the double helix structure of DNA and the related molecule RNA.

Though the element was widespread,, almost all phosphorus on the early Earth – around 4 billion years ago – was trapped in minerals that were essentially insoluble and unreactive. This means the phosphorus, while present in principle, was not available to make the compounds needed for life.

In a new paper (https://www.nature.com/articles/s41467-021-21849-2), we show lightning strikes would have provided a widespread source of phosphorus. This means lightning strikes may have helped spark life on Earth, and may be continuing to help life start on other Earth-like planets.

[Continues . . . (https://theconversation.com/origin-of-life-lightning-strikes-may-have-provided-missing-ingredient-for-earths-first-organisms-157343)]

The paper is open access--there's a link to it in the final paragraph quoted above.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Randy on March 18, 2021, 01:28:12 AM
For some reason that doesn't surprise me. I've always imagined that lightning would be the catalyst although I don't know why.
Title: Re: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: No one on March 18, 2021, 04:58:19 AM
Uhhhhh......... magic!
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: xSilverPhinx on March 18, 2021, 02:19:36 PM
Quote from: Randy on March 18, 2021, 01:28:12 AM
For some reason that doesn't surprise me. I've always imagined that lightning would be the catalyst although I don't know why.

You're probably thinking about the Miller–Urey experiment (https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment)? :notsure:
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Randy on March 18, 2021, 07:02:08 PM
Quote from: xSilverPhinx on March 18, 2021, 02:19:36 PM
Quote from: Randy on March 18, 2021, 01:28:12 AM
For some reason that doesn't surprise me. I've always imagined that lightning would be the catalyst although I don't know why.

You're probably thinking about the Miller–Urey experiment (https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment)? :notsure:
It could be I suppose. It's not ringing any bells for me.
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: xSilverPhinx on March 20, 2021, 01:02:53 AM
Quote from: Randy on March 18, 2021, 07:02:08 PM
Quote from: xSilverPhinx on March 18, 2021, 02:19:36 PM
Quote from: Randy on March 18, 2021, 01:28:12 AM
For some reason that doesn't surprise me. I've always imagined that lightning would be the catalyst although I don't know why.

You're probably thinking about the Miller–Urey experiment (https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment)? :notsure:
It could be I suppose. It's not ringing any bells for me.

I don't think there is a biology textbook that doesn't mention that experiment. :shrug:  :P
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Tank on March 20, 2021, 11:18:55 AM
Quote from: xSilverPhinx on March 20, 2021, 01:02:53 AM
Quote from: Randy on March 18, 2021, 07:02:08 PM
Quote from: xSilverPhinx on March 18, 2021, 02:19:36 PM
Quote from: Randy on March 18, 2021, 01:28:12 AM
For some reason that doesn't surprise me. I've always imagined that lightning would be the catalyst although I don't know why.

You're probably thinking about the Miller–Urey experiment (https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment)? :notsure:
It could be I suppose. It's not ringing any bells for me.

I don't think there is a biology textbook that doesn't mention that experiment. :shrug:  :P

I would suspect you're right. Except for creationist based biology text books that is :D
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: xSilverPhinx on March 20, 2021, 03:02:45 PM
Quote from: Tank on March 20, 2021, 11:18:55 AM
Quote from: xSilverPhinx on March 20, 2021, 01:02:53 AM
Quote from: Randy on March 18, 2021, 07:02:08 PM
Quote from: xSilverPhinx on March 18, 2021, 02:19:36 PM
Quote from: Randy on March 18, 2021, 01:28:12 AM
For some reason that doesn't surprise me. I've always imagined that lightning would be the catalyst although I don't know why.

You're probably thinking about the Miller–Urey experiment (https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment)? :notsure:
It could be I suppose. It's not ringing any bells for me.

I don't think there is a biology textbook that doesn't mention that experiment. :shrug:  :P

I would suspect you're right. Except for creationist based biology text books that is :D

Those are toilet paper,  not biology textbooks.  ;)
Title: Re: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: No one on March 20, 2021, 03:58:33 PM
Toilet paper already covered in shit is by definition, useless...........oh, I see what you did there.
Title: Re: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on March 20, 2021, 07:31:17 PM
Some Creationists are avid to discuss the Miller-Urey experiment as supposed evidence that abiogenesis is impossible. See for example the luminaries employed by Mr. Ham. A link to an archived page (https://archive.ph/lRWol).

QuoteSome museums may discuss the Miller-Urey experiment of 1953 as evidence that abiogenesis can occur. Anti-evolutionist Philip Johnson informs us:

QuoteBecause post-Darwinian biology has been dominated by materialist dogma, the biologists have had to pretend that organisms are a lot simpler than they are. Life itself must be merely chemistry. Assemble the right chemicals, and life emerges. DNA must likewise be a product of chemistry alone. As an exhibit in the New Mexico Museum of Natural History puts it, "volcanic gases plus lightning equal DNA equals LIFE!" When queried about this fable, the museum spokesman acknowledged that it was simplified but said it was basically true. (Phillip Johnson, Weekly Wedge Update, April 30, 2001, p. 1.)

This experiment actually showed that abiogenesis cannot occur.

[Continues . . . of course. (https://answersingenesis.org/kids/science/miller-urey-experiment/)]
Title: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Randy on March 20, 2021, 11:39:04 PM
Quote from: Tank on March 20, 2021, 11:18:55 AM
Quote from: xSilverPhinx on March 20, 2021, 01:02:53 AM
Quote from: Randy on March 18, 2021, 07:02:08 PM
Quote from: xSilverPhinx on March 18, 2021, 02:19:36 PM
Quote from: Randy on March 18, 2021, 01:28:12 AM
For some reason that doesn't surprise me. I've always imagined that lightning would be the catalyst although I don't know why.

You're probably thinking about the Miller–Urey experiment (https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment)? :notsure:
It could be I suppose. It's not ringing any bells for me.

I don't think there is a biology textbook that doesn't mention that experiment. :shrug:  :P

I would suspect you're right. Except for creationist based biology text books that is :D
Which is one line (easy to read), "Magic!"
Title: Re: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: xSilverPhinx on March 21, 2021, 01:34:30 AM
Quote from: No one on March 20, 2021, 03:58:33 PM
Toilet paper already covered in shit is by definition, useless...........oh, I see what you did there.

Pretty much :grin:
Title: Re: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: xSilverPhinx on March 21, 2021, 01:37:01 AM
Quote from: Recusant on March 20, 2021, 07:31:17 PM
Some Creationists are avid to discuss the Miller-Urey experiment as supposed evidence that abiogenesis is impossible. See for example the luminaries employed by Mr. Ham. A link to an archived page (https://archive.ph/lRWol).

QuoteSome museums may discuss the Miller-Urey experiment of 1953 as evidence that abiogenesis can occur. Anti-evolutionist Philip Johnson informs us:

QuoteBecause post-Darwinian biology has been dominated by materialist dogma, the biologists have had to pretend that organisms are a lot simpler than they are. Life itself must be merely chemistry. Assemble the right chemicals, and life emerges. DNA must likewise be a product of chemistry alone. As an exhibit in the New Mexico Museum of Natural History puts it, "volcanic gases plus lightning equal DNA equals LIFE!" When queried about this fable, the museum spokesman acknowledged that it was simplified but said it was basically true. (Phillip Johnson, Weekly Wedge Update, April 30, 2001, p. 1.)

This experiment actually showed that abiogenesis cannot occur.

[Continues . . . of course. (https://answersingenesis.org/kids/science/miller-urey-experiment/)]

Urgh, Ken Ham. I doubt he can tell the difference between a page from a good biology textbook and used toilet paper.
Title: Re: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
Post by: Recusant on November 15, 2022, 11:20:07 PM
Current research on the "water paradox (https://phys.org/news/2018-01-water-based-life.html)" (water is necessary for the processes of life, but loss of water is necessary for the basic compounds of life to form). This paradox is beloved of Creationists, but of course they also find it necessary to misrepresent the facts ("Water Paradox: Water Needed for Cells Yet Water Destroys Living Things" (https://archive.ph/gj9pD)). It seems to be a compulsion, which I suppose is understandable. The facts are not in their favor.

"Water was both essential and a barrier to early life on Earth – microdroplets are one potential solution to this paradox" | The Conversation (https://theconversation.com/water-was-both-essential-and-a-barrier-to-early-life-on-earth-microdroplets-are-one-potential-solution-to-this-paradox-192710)

QuoteIt's a paradox: Life needs water to survive, but a world full of water can't generate the biomolecules that would have been essential for early life. Or so researchers thought.

Water is everywhere. Most of the human body is made of it, much of planet Earth is covered by it and humans can't survive more than a couple of days without drinking it. Water molecules have unique characteristics that allow them to dissolve and transport compounds through your body, provide structure to your cells and regulate your temperature. In fact, the basic chemical reactions that enable life as we know it require water, photosynthesis being one example.

However, when the first biomolecules like proteins and DNA started coming together in the early stages of planet Earth, water was actually a barrier to life.

The reason why is surprisingly simple: The presence of water prevents chemical compounds from losing water. Take, for example, proteins, which are one of the main classes of biological molecules that make up your body. Proteins are, in essence, chains of amino acids linked together by chemical bonds. These bonds are formed through a condensation reaction that results in the loss of a molecule of water. Essentially, the amino acids need to get "dry" in order to form a protein.

[. . .]

Over the years, researchers have proposed many solutions to this "water paradox." Most of them rely on very specific scenarios on early Earth that could have allowed water removal. These include drying puddles, mineral surfaces, hot springs and hydrothermal vents, among others. These solutions, while plausible, require particular geological and chemical conditions that might not have been commonplace.

In our recent study, my colleagues and I found a simpler and more general solution to the water paradox. Quite ironically, it might be water itself – or to be more precise, very small water droplets – that allowed early biomolecules to form.

[Continues . . . (https://theconversation.com/water-was-both-essential-and-a-barrier-to-early-life-on-earth-microdroplets-are-one-potential-solution-to-this-paradox-192710)]