Is a new form of life really so alien?

May 08, 2012

The idea of discovering a new form of life has not only excited astronomers and astrobiologists for decades, but also the wider public. The notion that we are the only example of a successful life form in the galaxy has, for many, seemed like an unlikely statistic, as we discover more and more habitable planetary bodies and hear yet more evidence of life's ability to survive in extreme conditions. A new essay, published May 8 in the online, open-access journal PLoS Biology, examines what really constitutes 'life' and the probability of discovering new life forms.

Professor Gerald Joyce, from The Scripps Research Institute in La Jolla, California, discusses in the essay the basic requirements for a life form to exist. He says, "Life self-reproduces, transmits heritable information to its , and undergoes Darwinian evolution based on ." He refers to this heritable information as 'bits' (for life as we know it, this includes the four bases of DNA), and explains that although results in new combinations of these bits, this does not define a new or alien form of life. Indeed, to date no truly new life form has been discovered—either in extreme environments on Earth or on other planets—that contains new bits, despite evidence suggesting life on meteorites recovered in Antarctica, or on any of the so-called 'habitable' planets discovered in our galaxy.

How could a truly new life form arise? Joyce explains that an organism could either arise directly through chemistry, or spin off from existing biology. For the former, a life form would self-organize "into a bit-generating system." It's thought that this is how life originated on Earth; from a primordial soup of chemicals in an aqueous environment that generated self-replicating molecules, which then mutated and evolved. Joyce argues, "A life form that arises directly from bit-free chemistry would be considered 'new' from the outset, while one that derives from a biological cell would have a long way to go before reaching the threshold."

It is in these differences between chemical or biological initiation—that is to say, whether the life form has developed from an existing life or seemingly independently—that confusion and misinformation occurs surrounding the probability of a new life being discovered or created. Given that we only know of one life form—our own—we can't meaningfully estimate the probability of new life arising, either on Earth or elsewhere.

"I think humans are lonely and long for another form of life in the universe," says Joyce, "preferably one that is intelligent and benevolent. But wishing upon a star does not make it so. We must either discover alternative life or construct it in the laboratory. Someday it may be discovered by a Columbus who travels to a distant world or, more likely in my opinion, invented by a Geppetto who toils at the workbench."

In the accompanying Podcast, Joyce discusses in more depth the ability of scientists to discover the origin of novel life forms, and whether the emerging field of synthetic biology can actually lead to new forms of life.

Explore further: Reptile Database surpasses 10,000 reptile species

More information: Joyce GF (2012) Bit by Bit: The Darwinian Basis of Life. PLoS Biol 10(5): e1001323. doi:10.1371/journal.pbio.1001323

The accompanying podcast will be available here: blogs.plos.org/plospodcasts/

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NeutronicallyRepulsive
2.5 / 5 (4) May 08, 2012
I guess, there can be different base chemistry, different hereditary propagation mechanism (although mutation, and cloning principle will be common probably) or even possibly different additional selection mechanism (natural selection will be probably standard selection mechanism though) like self-controlled selection or something. Although it would be fascinating for the specialized scientists. I'm more interested in exotic pets (more complex organisms), cultural differences (intelligent beings), or of course technology (superior civilization >:D).
Telekinetic
2.1 / 5 (8) May 08, 2012
We would be the exotic pets of a superior civilization.
NeutronicallyRepulsive
3.4 / 5 (8) May 08, 2012
Telekinetic: Hopefully it would be a voluntary "petdom". I would play along - doing tricks, but I would wait for my moment to get hands on that XY technology in the living-room. "Look at him, he's so cute. He's playing with his nano-replicator. We got him from Sol system."
Lurker2358
1.4 / 5 (12) May 08, 2012
Life self-reproduces, transmits heritable information to its progeny, and undergoes Darwinian evolution based on natural selection.


Circular definition: Uses a theory derived to attempt to explain life as part of the definition of life.

logical fallacy.
gopher65
4.4 / 5 (14) May 08, 2012
Life self-reproduces, transmits heritable information to its progeny, and undergoes Darwinian evolution based on natural selection.


Circular definition: Uses a theory derived to attempt to explain life as part of the definition of life.

logical fallacy.

You demonstrate a lack of understanding of what the Theory of Evolution encompasses. Evolution is merely what happens to life *after* it has started, and has nothing to do with *how* life starts. Created life and abiogenic life would both evolve, irrespective of how they came into existence.

As I implied above, the abiogenesis is what is used to explain how life could start on its own. It is completely separate from evolution.
verkle
1 / 5 (16) May 09, 2012
The article states that "we can't meaningfully estimate the probability of new life arising, either on Earth or elsewhere."

I totally disagree. We can meaningfully estimate such a probability, and the number would be so small that most computers would have to spit out just a plain "0"!

But some scientists still continue to ignore this fact and think that they somehow have appeared on this earth by chance! Just blows my mind away! (No---I do still have a mind)

Telekinetic
3.9 / 5 (11) May 09, 2012
Verkle, you're too old to be an altar boy, and it's nauseating to read your insinuations of intelligent design. Proof is required for that type of assertion. If you permanently disappeared from Physorg, I might interpret that as a miracle.
antialias_physorg
5 / 5 (9) May 09, 2012
I totally disagree. We can meaningfully estimate such a probability, and the number would be so small that most computers would have to spit out just a plain "0"!

Then you have not an inkling of an idea what probabilities (and statistics) mean and how they work. Please google for a tutorial.
TabulaMentis
1 / 5 (8) May 09, 2012
From article:
I think humans are lonely and long for another form of life in the universe.
The Holy Ghost is one that people continue to say does not exist even though it has been sighted numerous times. It is the most subtle of all creatures, it flies and has no wings. I guess it is too advanced for humans to comprehend.
antialias_physorg
5 / 5 (8) May 09, 2012
even though it has been sighted numerous times

Pics or GTFO.
TabulaMentis
1 / 5 (6) May 09, 2012
Pics or GTFO.
The sightings have been well documented over the years Big Mouth!
antialias_physorg
5 / 5 (7) May 09, 2012
The sightings have been well documented over the years Big Mouth!

By? Verifiable? I'm all agog.

Or are we talking hear-say? Like UFOs nor the Loch Ness monster (they at least have pics occasionally)
TabulaMentis
1 / 5 (6) May 09, 2012
Or are we talking hear-say? Like UFOs nor the Loch Ness monster (they at least have pics occasionally).
By: Religious texts going back thousands of years. Verifiable: Paintings going back hundreds to thousands of years. Oh yeah, everybody believes in UFOs and Loch Ness Monsters just like everybody believes in the Holy Ghost and its evil twin.
DarkHorse66
5 / 5 (4) May 10, 2012
By: Religious texts going back thousands of years. Verifiable: Paintings going back hundreds to thousands of years. Oh yeah, everybody believes in UFOs and Loch Ness Monsters just like everybody believes in the Holy Ghost and its evil twin.

What real knowledge did their writers/painters have?Only what they inferred without really understanding.Even if God HAD given them the knowledge, what could they have made of it?Their sense of the world was limited, mysterious/mythical and they thought it was flat.Any 'science'was of the Aristotelian type.This relies more on reasoning than anything else http://en.wikiped...c_method If you were to tell them about subatomics & genetics, do you REALLY think they would have been able to make sense of it?That would have sounded like magical mumbo jumbo to them.Most likely, you would have dumbed-down your lesson massively. As He is 'all-knowing',your God would have known this too.And waited for knowledge to catch up
antialias_physorg
5 / 5 (9) May 10, 2012
Religious texts going back thousands of years.

Verifiable: Paintings going back hundreds to thousands of years

So you are saying the evidence is even less so than for ghosts, UFOs , Loch Ness monsters, Yetis and whatnot.

You are aware that those texts and pictures you cite are fictional representations?

And even in the stupendously unlikely event that those things were based on fact: Why was it so easy to come by this crap thousands of years ago and today it's not? In the novels god seemed to talk to his prophets in no uncertain terms and pretty visible (burning bushes and whatnot). How do you explain that it went into hiding as soon as there was actually a chance to make its presence indubitably known?

You just fell for the longest con in history - and not one without ptrecedent, too. Because there have been many pantheons before yours that you would call fictional (egyptian, greek/roman, babylonian, ...). They, too, had books thousands of years old. And paintings.
TabulaMentis
1 / 5 (7) May 10, 2012
So you are saying the evidence is even less so than for ghosts, UFOs , Loch Ness monsters, Yetis and whatnot.
Really now, who out there actually believes in the evidence that UFOs and Loch Ness Monsters exist. You must be referring to photographs or peoples sightings as evidence. Come on, why would paintings and peoples sightings years ago not be as credible as the people of today? Doctored photographs or video footage is your proof? Why would people doctor the paintings thousands of years ago and mislead people with false texts?
TabulaMentis
1 / 5 (4) May 10, 2012
Knight Sir George Frankenstein was killed by a dragon around 1500 AD, but I wish you good luck in convincing people that story is true. If only there were cameras back then.
CHollman82
5 / 5 (6) May 10, 2012
hear-say from thousands of years ago is infinitely less credible than hear-say from today. People have an unwarranted respect for the ancient, because they have a lack of respect (or lack of understanding of) modern knowledge.
antialias_physorg
5 / 5 (9) May 10, 2012
peoples sightings years ago not be as credible as the people of today

Exactly. You disbelieve doctored accounts today. Why do you believe doctored accounts from a thousand years ago?
Why do you believe in the bible and not the egyptian writings about their gods? What exactly is the difference to you about these two forms of 'evidence'?

Knight Sir George Frankenstein was killed by a dragon around 1500 AD, but I wish you good luck in convincing people that story is true.

Jesus was born 2000 years go (without pics), but I wish you good luck in convincing people that story is true.

Why would people doctor the paintings thousands of years ago and mislead people with false texts?

The same reason witch-doctors and shamans have done it since the dawn of time:
"Me big man. Me know secret. Me commune with gods. Me can plead on your behalf. You go out get me biggest piece of meat while me sit in comfy chair in biggest hut"

Lying is profitable.
TabulaMentis
1 / 5 (6) May 10, 2012
Maybe someday when you stop believing everything came nothing will you begin to understand that there is something out there smarter and more powerful than you.

In the meantime, just to let you know, I love the idea of UFOs (metallic and non-metallic versions such as the Holy Ghost), Loch Ness monsters (including dragons), yetis, ghosts, orbs (made by intelligent life forms) and a creator who lives in a cube outside of our universe.

All of them are alien life forms.
CHollman82
4.3 / 5 (6) May 10, 2012
Maybe someday when you stop believing everything came nothing will you begin to understand that there is something out there smarter and more powerful than you.


Where did that thing come from? Nothing?

In the meantime, just to let you know, I love the idea of UFOs (metallic and non-metallic versions such as the Holy Ghost), Loch Ness monsters (including dragons), yetis, ghosts, orbs (made by intelligent life forms) and a creator who lives in a cube outside of our universe.

All of them are alien life forms.


Stupidity.
TabulaMentis
1 / 5 (4) May 10, 2012
Where did that thing come from? Nothing?
Everything came from somethingness, but you are so ignorant you can not figure out what that somethingness is!

Stupidity
No, it is ignorance on your part!
CHollman82
4 / 5 (4) May 10, 2012
Where did that thing come from? Nothing?
Everything came from somethingness, but you are so ignorant you can not figure out what that somethingness is!

Stupidity
No, it is ignorance on your part!


Lawrence Krauss, a theoretical physicist who received his PhD from MIT and who later taught at Yale, gives a presentation titled "A universe from nothing"... watch it and learn what real top physicists who actually study and understand this stuff think:

http://www.youtub...Yw59ztyw
CHollman82
4 / 5 (4) May 10, 2012
Look up his bio, and if you still think your opinion has equal weight with his then you're a complete fucking idiot, there's no way to sugar coat that.

http://en.wikiped...._Krauss
TabulaMentis
1 / 5 (4) May 10, 2012
Look up his bio, and if you still think your opinion has equal weight with his then you're a complete fucking idiot, there's no way to sugar coat that.

http://en.wikiped...._Krauss
Like the old saying goes: "From nothing comes nothing." Your hero Lawerence Krass with his PhD from MIT is also an ignorant fool like you!
CHollman82
3.7 / 5 (3) May 10, 2012
...and you've lost all credibility.
CHollman82
3.4 / 5 (5) May 10, 2012
As usual, the uneducated or spuriously educated creationists have to butt heads with leaders of the relevant scientific fields in order to attempt to support their untenable positions.

Thinking that you are on an equal intellectual footing with these scientists and that your opinions are worth anything in light of theirs is nothing short of delusional.
MandoZink
5 / 5 (4) May 12, 2012
For decades we've been randomly mixing primordial chemicals together and zapping them in an attempt to reproduce the basic molecules for RNA, which self-replicates. Those efforts had produced a lot of amino acids, but no complete ribonucleotides. Recently, it was realized that these molecules might have been created in steps, not by just wholesale mixing and zapping.

A new approach using primordial chemicals and conditions was tried with this idea, and they quickly discovered that two of the nucleotides, cytosine and uracil, were easily created. Once they deduce how adenine and guanine were formed we'll see abiogenesis moving to solid ground.

RNA world easier to make:
http://www.nature...471.html

I hope it has as great an effect as the elimination of the "prime rover", or "first cause" theory of Aristotle, which Isaac Newton put to rest.
MandoZink
5 / 5 (2) May 12, 2012
Excuse me. I did not mean to imply Aristotle had "rovers". Maybe he did. In this day and age, he probably would. But I meant to say "prime MOVER" - the idea that... well, since we gotta explain it somehow, we'll mend it with "Plug-in-a-God".

I do think it was a good thing at the time, but our road to greater intellect eventually lets us fix those shortcomings. I wish some people would understood our need to give up those "placeholders" when knowledge finally covers the gap.

"God was my copilot once, but we crashed in the mountains and I had to eat him." - unknown
Norezar
not rated yet May 12, 2012
Telekinetic: Hopefully it would be a voluntary "petdom". I would play along - doing tricks, but I would wait for my moment to get hands on that XY technology in the living-room. "Look at him, he's so cute. He's playing with his nano-replicator. We got him from Sol system."


Personally I would be so up for this.

I'm even mostly house broken and capable of refraining from humping strange legs.

Usually.
Vendicar_Decarian
not rated yet May 12, 2012
Where did the nothing come from?

"Everything came from somethingness" - Tabumentis
MandoZink
5 / 5 (3) May 12, 2012
By: Religious texts going back thousands of years. Verifiable: Paintings going back hundreds to thousands of years.

Much of the content in the Old Testament came from sources as varied as Paganism and Zoroastrianism - and beyond. They were altered for whatever reasons to fit whatever purpose. The Essenes, among other sects, often altered texts to dis-inform their persecutors.

Then again, repeated translations consistently misinterpret idioms, metaphors and hyperboles no longer recognized by the translators. One local word for "month" might be another region's word for "year", thus Methuselah's extended age.

The translations were often skewed to benefit those in authority. Only those in power were allowed to oversee the "proper" interpretation, which was always to their benefit.

I could go on and on.
MandoZink
5 / 5 (3) May 12, 2012
The Holy Ghost is one that people continue to say does not exist even though it has been sighted numerous times. It is the most subtle of all creatures, it flies and has no wings. I guess it is too advanced for humans to comprehend.

There is no evidence whatsoever in ancient scriptures that mental illnesses, such as schizophrenia, were recognized in humans. Instead, the scriptures recorded visions, apparitions and possessions with regularity. Coincidentally, we now know that these are hallmarks of mental illness or chemical imbalances which are diagnosable and often correctable. In modern society, these same people who weren't recognized as ill then are the ones who have visions.

On another note, the Loch Ness hoax was exposed a few years back when someone discover the actual series of pictures that were taken in 1933 of a circus elephant swimming in the Loch. Circuses often traveled the Loch while visiting Inverness in Scotland. I saw them. One of them was the infamous photo.
MandoZink
5 / 5 (1) May 13, 2012
OK. Wanna see a good 4-minute tirade on Creationism?
http://www.youtub...=related

Funny.