Life from non-life. Fact or Fiction?

Well, in the most technical sense, even Christians believe in life from non-life, since no Christian conception of God matches up with the scientific definition of life.

It's not *only* creation/evolution, but also science in general. Abiogenesis theories are a lot of fun, and I'd assume we could debate them.

I agree with seebs, it can be a fun discussion and really is fascinating to speculate IMO. Where would you like to start?

We know that abiogenesis happened because there is life here...and there is no special "life" element...living things are made up of carbon, hydrogen, etc. Even creationists have to accept some form of abiogenesis, only they think that God made man from dust

Basically science does not make assertions about how abiogenesis happened (therefore no FACTS per se), but is still in the hypotheses stage AFAIK

Interestingly, creationists claim man was made from dust, yet science is unable to find things in our physical makeup which is like the dirt of the MidEast--or anywhere else. You would expect our DNA is have some consistency with "dust". I suppose the ad hoc excuse is we don't know what kind of "dust" God used?

DNAunion: Here's an overview of one scenario. (If someone doesn't understand certaing terms, just ask). Let's start by working backwards.

About 3.5 billion years ago, there was a "single cell" from which all other cells evolved: that includes the cells that make up humans, birds, flatworms, squids, fruitflies, pine trees, etc. This "single cell" is known by many names, such as the MRCA (most-recent common ancestor), the UCA (universal common ancestor), the LUCA (last universal common ancestor), etc. It was very much like a modern day cell. It had a cell membrane, its genetic material was DNA, it used all three RNAs (tRNA, mRNA, and rRNA) to synthesize proteins, had ribosomes, etc.

How did it arise? Phospholipid bilayer sheets form and then ball up into a liposome, spontaneously, when phospholipids are introduced into water. It has been shown that large molecules such as polymerases can become captured on the inside of such liposomes. So if any single liposome was lucky enough to have captured all of the components of a self-replicating system, you would have a crude cell.

As far as self-replication, it may have arisen in RNA. RNA, possessing four bases (A, C, G, and U) just like DNA (A, C, G, and T), can store information (some viruses have only RNA as their genome). It was found in the 1980s that some RNA molecules are also catalytic - that is, they accelerate the rate of biochemical reactions without themselves being permanently altered in the process. So it is possible that a given RNA molecule could both store genetic information and catalyze its own replication. This is actually pretty important because it can potentially do away with the chicken-or-egg paradox dealing with DNA, RNA, and proteins (in extant cells, DNA replication requires proteins, yet proteins are coded in DNA; proteins are needed to make RNA, yet RNA is needed to make proteins; etc.).

However, many OOL researchers feel that RNA is not prebiotically plausible, and so have looked for a simpler (and many times achiral) molecule that could have initiated self-replication, with RNA eventually taking over. One such candidate is PNA (peptide nucleic acid).

So, going in the foward direction now, here's the basic idea.

Random chemical reactions on the primitive Earth had molecules combining, breaking apart, reforming new combinations, and so on for multiple millions of years. By chance, many somewhat complex biologically relevant molecules - such as sugars - were formed. If they went on to react with other (appropriate) complex molecules, then more complex molecules could have formed (chemical complexification). Somewhere along the line, something like PNA could have arisen. If enough PNA arose, one of the strands may have been lucky enough to have possessed a sequence capable of self-replication. The PNA used RNA for some reason, and over time, parts of its own self-replicating system were gradually replaced with RNA counter parts. Eventually, RNA became the self-replicating molecule. But not all RNA produced functioned for self-replication; some performed other functions, such as forming peptide bonds between amino acids, even if only weakly. Eventually, by chance, a peptide was formed that benefited the whole system somehow, and the function of making proteins became important for the RNA organism. At some point, a protein that could reduce RNA arose, and, because this reduced form of RNA (deoxyribonucleic acid - DNA) was more stable than RNA, it eventually took over the role of storing the genetic information. At some point along the way, all of this became encapsulated in a liposome, which provided protection and concetration. And when the contents increased past a certain point - internal growth due to the continual action of the encapsulated self-replicating machinery - the liposome split in two: a crude form of cell reproduction.

And that would get us far enough, since this is just a basic overview of one scenario.

Originally posted by Humanista
Interestingly, creationists claim man was made from dust, yet science is unable to find things in our physical makeup which is like the dirt of the MidEast--or anywhere else. You would expect our DNA is have some consistency with "dust". I suppose the ad hoc excuse is we don't know what kind of "dust" God used?

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Perhaps, we were simply created from the existing elements of the earth?

When will people learn that it wasn't evolution, or creation of the bible, but aliens. Why do you think so many people are seeing ufos, and being abducted? Well they are come back to check up on there "creation".

Originally posted by DNAunion
DNAunion: Here's an overview of one scenario. (If someone doesn't understand certaing terms, just ask). Let's start by working backwards.

About 3.5 billion years ago, there was a "single cell" from which all other cells evolved: that includes the cells that make up humans, birds, flatworms, squids, fruitflies, pine trees, etc. This "single cell" is known by many names, such as the MRCA (most-recent common ancestor), the UCA (universal common ancestor), the LUCA (last universal common ancestor), etc. It was very much like a modern day cell. It had a cell membrane, its genetic material was DNA, it used all three RNAs (tRNA, mRNA, and rRNA) to synthesize proteins, had ribosomes, etc.

How did it arise? Phospholipid bilayer sheets form and then ball up into a liposome, spontaneously, when phospholipids are introduced into water. It has been shown that large molecules such as polymerases can become captured on the inside of such liposomes. So if any single liposome was lucky enough to have captured all of the components of a self-replicating system, you would have a crude cell.

Click to expand...

Allow me to start here.  Your original cell you state was very much like modern day cells, containing a cell membrane, with genetic material.

What about a nucleus?  Does your model of an originating cell account for a nucleus? or did that cell component occur later?

What about cytoplasm?  the 'cream filling' of modern cells where the chemical reactions of the cell take place.  Currently cytoplasm contains sugars, amino acids, and proteins to carry out these reactions.  Yet, you state that sugars associated with modern cells developed later in the proposed chain of events.

The membrane of a cell is quite complex within itself.  It serves as a filter to the cell, allowing the in-out process of certain compounds enter/exiting the cell, while blocking others.

My initial question is: What would be the process proposed for the formation of such a complex (filter) i.e. membrane?  And does the ancesteral cell theory account for the formation of a nucleus..or did that occur later?

Regards,

Smilin

Originally posted by seesaw
When will people learn that it wasn't evolution, or creation of the bible, but aliens. Why do you think so many people are seeing ufos, and being abducted? Well they are come back to check up on there "creation".

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puuuulleeaasseee seesaw..

EVERYONE knows that aliens didn't create us...they're simply abducting rural uneducated people in trailor parks for the purpose of scientific research, organ harvesting, and food sources.

We're not their creation...we're their 'cattle'.  

Originally posted by DocBrown
Can we discuss Abiogenesis here? I realize this isn't evolution but it does seem to relate somewhat, everything had to have had a beginning right?

If this isn't the place to discuss this then can someone direct me to the right place?

If not then I'd like to hear some facts about life coming from non-life.

Thanks, 

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Go to the thread "Protocells: life from non-life".

Want facts? Go to http://www.siu.edu/~protocell/
http://www.theharbinger.org/articles/rel_sci/fox.html to start.  On the first, make sure you read the linked pages, don't stop with the first one.

Originally posted by Smilin
puuuulleeaasseee seesaw..

EVERYONE knows that aliens didn't create us...they're simply abducting rural uneducated people in trailor parks for the purpose of scientific research, organ harvesting, and food sources.

We're not their creation...we're their 'cattle'.  

Click to expand...

Oh... I guess that makes more sense.

Originally posted by DNAunion How did it arise? Phospholipid bilayer sheets form and then ball up into a liposome, spontaneously, when phospholipids are introduced into water. It has been shown that large molecules such as polymerases can become captured on the inside of such liposomes. So if any single liposome was lucky enough to have captured all of the components of a self-replicating system, you would have a crude cell.

That's one possibility, but it begs the question of where the polymerase came from.

As far as self-replication, it may have arisen in RNA. RNA, possessing four bases (A, C, G, and U) just like DNA (A, C, G, and T), can store information (some viruses have only RNA as their genome). It was found in the 1980s that some RNA molecules are also catalytic - that is, they accelerate the rate of biochemical reactions without themselves being permanently altered in the process. So it is possible that a given RNA molecule could both store genetic information and catalyze its own replication. This is actually pretty important because it can potentially do away with the chicken-or-egg paradox dealing with DNA, RNA, and proteins (in extant cells, DNA replication requires proteins, yet proteins are coded in DNA; proteins are needed to make RNA, yet RNA is needed to make proteins; etc.).

1.  Not all proteins are coded by DNA.  Even in modern cells.

2. Some proteins also replicate themselves and replicate other proteins.

3.  RNA can make itself.  RJ Davenport, Making copies in the RNA world.  Science 292: 1278, May 18, 2001. Used in vitro evolution to make ribozyme that can faithfully copy other RNA molecules up to 14 nucleotides long.    Uses any RNA as sequence as template. Ribozyme itself is 189 nucleotides long.  98.5% accurate (99.9% for RNA polymerase).  Screened 10^15 ribozymes.  Primary paper is WK Johnston, PJ Unrau, MS Lawrence, ME Glasner, DP Bartel, RNA-catalyzed RNA polymerization: accurate and general RNA-templated primer extension. Science 292: 1319-1326, May 18, 2001.

Random chemical reactions on the primitive Earth had molecules combining, breaking apart, reforming new combinations, and so on for multiple millions of years. By chance, many somewhat complex biologically relevant molecules - such as sugars - were formed.

Not random nor chance. Chemistry isn't chance.

If they went on to react with other (appropriate) complex molecules, then more complex molecules could have formed (chemical complexification). Somewhere along the line, something like PNA could have arisen. If enough PNA arose, one of the strands may have been lucky enough to have possessed a sequence capable of self-replication. The PNA used RNA for some reason, and over time, parts of its own self-replicating system were gradually replaced with RNA counter parts. Eventually, RNA became the self-replicating molecule....

This is the RNA-world hypothesis.  As you say, one among many.

But I doubt that the first membrane was lipid. Proteins do well as membranes. After all, today's cells have 60% of their membranes are protein.  Protein is also amphiphilic (both water-hating and water loving regions).

Originally posted by Smilin
What about cytoplasm?  the 'cream filling' of modern cells where the chemical reactions of the cell take place.  Currently cytoplasm contains sugars, amino acids, and proteins to carry out these reactions.  Yet, you state that sugars associated with modern cells developed later in the proposed chain of events.

The membrane of a cell is quite complex within itself.  It serves as a filter to the cell, allowing the in-out process of certain compounds enter/exiting the cell, while blocking others.

My initial question is: What would be the process proposed for the formation of such a complex (filter) i.e. membrane?  And does the ancesteral cell theory account for the formation of a nucleus..or did that occur later?

Regards,

Smilin

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The cytoplasm.  Dissolved in the water of the time would be a mixture of sugars, amino acids.  This mixture would be enclosed by DNAUnion's liposomes to be the cytoplasm.

One reason the protocell hypothesis is popular is that it has a semi-permeable membrane -- made of protein.  In that hypothesis, lipids were incorporated into membranes later.

The common hypothesis is that eukaryotic cells -- those with a nucleus -- came later. Remember, all bacteria and archea are prokaryotes: they don't have a nucleus.

There is a minor hypothesis that eukaryotes came first and that prokaryotes are a simplification of them.  The protocell hypothesis has multiple layers of proteins in nested spheres.  In this hypothesis, the inner sphere would be the nucleus.

Originally posted by lucaspa
Go to the thread "Protocells: life from non-life".

Want facts? Go to http://www.siu.edu/~protocell/
http://www.theharbinger.org/articles/rel_sci/fox.html to start.  On the first, make sure you read the linked pages, don't stop with the first one.

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wow...very interesting link lucaspa...

protocells from thermal proteins...

any further research showing the mechanism for protocells developing into higher order cells we observe today?

Originally posted by Smilin
wow...very interesting link lucaspa...

protocells from thermal proteins...

any further research showing the mechanism for protocells developing into higher order cells we observe today?

Click to expand...

Wrong process.  Protocells form by chemistry.  "developing into higher order cells we observe today" requires evolutionary processes.  However, there is data that

1. Protocells, because they reproduce and "inherit" the material of the parent, can be be selective units for natural selection.

2. Some thermal proteins have affinity for particular sequences of bases in DNA. This forms the basis of DNA coding of proteins.

3. You already read that the thermal proteins catalyze the synthesis of nucleic acids.

4. Protocells have membrane potentials and discharge those potentials just like today's nerve cells.

The sequence to get you to modern cells is:

1.  Formation of amino acids from primordial precursors (water, ammonia, carbon dioxide, methane, oxygen, hydrogen, etc.) [M-U experiments and Miller and Orgel].
2.  Formation of proteinoids by polymerization of sets of amino acids.  [Fox and others].
3.  Formation of microspheres by contact of proteinoids with water [Fox and others].
4.  Synthesis of RNA within the microspheres [Fox]
5.  Replication of RNA. [Orgel]
6.  Development of the genetic code.
The first 5 steps have been done in the lab.  The last one is being worked on.  There are several papers out there discussing possible ways it could happen.  The difficulty is going to be deciding how it actually happened.

http://www.strbrasil.com.br/English/Scientia/life.htm 
1.  Alberti, S The origin of the genetic code and protein synthesis. J. Mol. Evol. 45: 352-358, 1997. 
7.  P S Chimmel and R Alexander, All you need is RNA.  Science 281:658-659, Jul. 31, 1998.  Describes research showing that RNA in ribosomes sufficient to make proteins. Intermediate step in going from abiogenesis to genetic code.
9.  AM Poole, DC Jeffares, D Penney, The path from the RNA world.  J. Molecular Evolution 46: 1-17, 1998.  Describes Darwinian step-by-step for evolution from RNA molecules to cells with directed protein synthesis. All intermediate steps are useful.

Notice that the last one explicitly uses the process of evolution: Darwinian selection.

This thread is being abducted by atheists

Originally posted by JesusServant
This thread is being abducted by atheists

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Non-atheists can interrupt at any given time.

It is difficult to counter rational thinking. First abiogenesis does not claim to have proof. I can not ask what they do not give. We are comprised out of basic element and molecules. Without the proof of God the conclusion that we somehow formed out of those elements, molecules and components is rational.

What I did is to place those basic building blocks in my computer and looked at the required interaction with the help of bio-chemists and biologists. Sure, it is possible. What I seriously question are the required events for the said Ur-cell to happen. There, I think, is where abiogenesis uses circular reasoning. It says: This is how the cell may have formed. The required events for that must have happened.

So in my opinion, for now, abiogenesis requires believe.