Freethought & Rationalism Archive

Fiach · 03-29-2003, 08:19 PM

Quote:

Originally posted by scigirl
I'm having a tough time understanding your argument here, DNAunion.

Soap bubbles exhibit replicative characteristics that would have been important in the replication of early cell membranes. That's my take on it.

But it is only a distant analogy. Soap bubbles may superficially resemble cell membranes. But it is only a simple physical effect on water surface tension of water that allows the soap bubbles. They are just soapy water around an air pocket. That hardly qualifies for life. Many things replicate but are not quite life. Some proteins in an amino acid soup may do this but they are not alive but only chemical catalysts for amine bonding reactions. Not life. Cell membranes are more complex. They cannot replicate. When a cell grows or mitoses into two new cells, it is because the double layered lipoprotein membraine with its many ion channels and quanta release points, are determined by DNA coding RNA acting on Mitochronria, with transport to the surface by the Golgi apparatus. Carrier proteins regulate the transport. And separate codes promote the production of the various ion channels (sodium pumps, sodium channels, calcium channels, surface receptors each of its own complexity.) All of the building of the cell wall is a complex multi-stage process by DNA guidance from the nuclei. That is life.

I think about it this way:

IF it is true that cells emerged on the Earth without the necessity of guidance from some deity or alien, THEN there must be chemical and physical explanations as to how this could have occured. So - can we show that DNA and RNA can self-replicate? Probably. Can we show that proteins are capable of assembling into complex structures? Definitely. Can lipid membranes assemble and disassemble such that two bubbly things can come from one bubbly thing? Yes they can. Put all this stuff together and you have a cell.

See my paragraph above.

Now, does that mean that any replicating piece of RNA, or spontaneiously assembling protein complex, or splitting off-lipid, is alive? No, no-one is saying that. These phenomenon simply show that as far as we know, there are no physical or chemical barriers to life assembling. Thus - abiogenesis could have happened without the need of a non-natural explanation.

I think that there is no hard solid line separating non-life from life. There are replicating things that are not cells, viruses and PRIONS. Are they alive? They meet most of the requirements, in that they replicate, invade and parasitise cells, take over that cell and use its mitochondria and altered DNA to make more of itself. Soap bubbles don't enter your liver and bubble out of your nose.

Maybe it would help, DNAunion, if you could outline what your position is regarding the possibility or impossibility of abiogenesis.

I'll give my answer. Abiogenisis if we use that world to describe natural processes that lead to life, then I say that it is the most plausible explanation if not yet proven. And we have no alternative explanations apart from Divine Magic for which there is no evidence.

scigirl

Slainte mhaith,

Fiach

DNAunion · 03-30-2003, 03:39 PM

Quote:

Scigirl: Now, does that mean that any replicating piece of RNA, or spontaneiously assembling protein complex, or splitting off-lipid, is alive? No, no-one is saying that.

DNAunion: I think someone is.

Lucaspa asserts that he fried up actual living cells on his stove at home, using nothing but amino acids and water.

PS: Lucaspa is the person that the poster who brought up proteinoid microspheres originally in this thread mentioned.

Doubting Didymus · 03-30-2003, 03:45 PM

Quote:

Originally posted by DNAunion
DNAunion: I think someone is.

Lucaspa asserts that he fried up actual living cells on his stove at home, using nothing but amino acids and water.

PS: Lucaspa is the person that the poster who brought up proteinoid microspheres originally in this thread mentioned.

Do you suppose he is talking about chicken eggs?

Principia · 03-30-2003, 03:51 PM

Why, not chicken eggs at all.

Let's all read what lucaspa had to say actually about the matter of Fox's protocells, here (this is lucaspa's take on the subject), and here (this is DNAunion's caricature of it, as he did above), rather than take DNAunion's word for it.

Fiach · 03-30-2003, 05:46 PM

Quote:

Originally posted by Principia
Why, not chicken eggs at all.

Let's all read what lucaspa had to say actually about the matter of Fox's protocells, here (this is lucaspa's take on the subject), and here (this is DNAunion's caricature of it, as he did above), rather than take DNAunion's word for it.

We only have two possible broad categories to classify the origin of everything: Natural processes and Divine Magic.

We don't have a complete mechanism yet for abiogenesis, but we have possible scenarios and the necessary ingredients for life on early Earth. A full theory is yet to be developed.

On the other side, life was created in a hocus-pocus word conjuring Magic Act by a hypothetical God. For this set of possibilities we have absolutely no evidence. Many of those folks even deny the fact of evolution whether natural or magical design. In fact there is not a shred of evidence for any god/creator.

So that is our choice. We know that most things occur by way of their natural properties in natural processes. Abiogenesis is plausible but not yet proven. Our choice is between a plausible origin by natural processes (knowing that natural processes abound) versus origin by Magical conjuring realising that no magical even has ever been proven, the divine magician is entirely imaginary without evidence.

So take your choice until more evidence shifts the balance.

Fiach

Principia · 03-30-2003, 06:02 PM

Quote:

We only have two possible broad categories to classify the origin of everything: Natural processes and Divine Magic.

I have no idea if you're writing to me, directly. But I'll address this dichotomy. To be fair, I think the actual divide is between What-is-comprehensible and What-is-incomprehensible. So if it's "divine magick" and we can comprehend it fully, then as far as I am concerned it's just good enough for me. If whichever God shows up one day and gives us His divine lab notebook on how he created everything, then I am perfectly content. We can leave the debate about whether this cause is actually "divine" or "natural" to the theologians and philosophers. But, what I can't allow is something that is not only divine, but whose very existence is purportedly beyond human comprehension. For me, that's just a redundant way of saying I-dunno.

Thanatoast · 03-30-2003, 07:50 PM

Ok, sorry for not responding sooner (I have exams to study for!):
DNAunion said:

Quote:

DNAunion: So when my cars' tires change over time as the tread is worn from driving, that's biological evolution?

Then scigirl retorted:

Quote:

Christ, DNAUnion, I think we can assume some basic facts. When someone is talking about evolution, they mean heritable change over time.

DNAunion shot back:

Quote:

DNAunion: Hmmm....then why didn't that person just say that? Why did he/she say biological evolution was simply "change over time"? I was pointing out what I saw as ironic. He/she was basically belittling the other person for not knowing what evolution was, and in the process told us what evolution was: but as stated, it wasn't even close.

OK, first of, I'm a he.

Secondly, I was not belittling anyone. I was merely stating my surprise as to how this intricate discussion of abiogenesis sprang from Jobar's recounting his introductory defense of evolution to a "fundie", as he put it, without mentioning the basics that, IMO, should be part of any such explanation. I'm sure Jobar knows what "evolution was", as most of us here do.

While it's true Jobar's OP included a specific request for information reqarding abiogenesis, it was in the context of his retelling his presentation of the evolutionary paradigm to one who holds creationist beliefs. It was the lack of including the basics in his OP, inluding "change over time", that surprised me.

DNAunion apparently sees this as too basic. Perhaps my inclusion of the word "simply" was unwarranted. Perhaps I should have replaced it with "heritable", as scigirl did. But I think pz aptly puts this word usage into perspective:

Quote:

Oh, please. Any time someone has to express a brief definition of biological evolution, it's going to be incomplete, and a petty pedant can nitpick to a ridiculous degree...especially if they want to ignore the context and the general significance of the comment. You do not win points for trivia here.

Thanks for the vote of confidence, pz.

Now, please continue the abiogenesis discussion. I'm learning a great deal, as I'm sure many others are.

Fiach · 03-30-2003, 09:05 PM

Quote:

Originally posted by Principia
I have no idea if you're writing to me, directly. But I'll address this dichotomy. To be fair, I think the actual divide is between What-is-comprehensible and What-is-incomprehensible. So if it's "divine magick" and we can comprehend it fully, then as far as I am concerned it's just good enough for me. If whichever God shows up one day and gives us His divine lab notebook on how he created everything, then I am perfectly content. We can leave the debate about whether this cause is actually "divine" or "natural" to the theologians and philosophers. But, what I can't allow is something that is not only divine, but whose very existence is purportedly beyond human comprehension. For me, that's just a redundant way of saying I-dunno.

I don't think we disagree on principles.

Fiach

Fiach · 03-30-2003, 09:21 PM

Quote:

Originally posted by Thanatoast
Ok, sorry for not responding sooner (I have exams to study for!):

Secondly, I was not belittling anyone. I was merely stating my surprise as to how this intricate discussion of abiogenesis sprang from Jobar's recounting his introductory defense of evolution to a "fundie", as he put it, without mentioning the basics that, IMO, should be part of any such explanation. I'm sure Jobar knows what "evolution was", as most of us here do.

Jobar is well versed on science and evolution. In explanations to fundies we have to use simple language (talking down to) them because they are scientifically illiterate. If they were not scientifically illiterate they would be able to understand Evolutionary mechanisms, the most complex areas of biology apart from higher biological neurobehaviour.

While it's true Jobar's OP included a specific request for information reqarding abiogenesis, it was in the context of his retelling his presentation of the evolutionary paradigm to one who holds creationist beliefs. It was the lack of including the basics in his OP, inluding "change over time", that surprised me.

Please see my post above for an explanation that while we know evolution as a fact, we infer the transition from replicating molecules to cells without having a specific mechanism proven.

DNAunion apparently sees this as too basic. Perhaps my inclusion of the word "simply" was unwarranted. Perhaps I should have replaced it with "heritable", as scigirl did. But I think pz aptly puts this word usage into perspective:

Thanks for the vote of confidence, pz.

Perhaps.

Now, please continue the abiogenesis discussion. I'm learning a great deal, as I'm sure many others are.

There is not much more to continue on this. We have tantalising evidence of micro-organisms resembling mitochondria, vacuoles, Nuclei and viral DNA in old pre-Cambrian fossils (750 million years old) that seem to have come together by an unknown mechanism to make cells. My hypothesis as a geneticist is that DNA with makes proteins and regulates their use, eventually produced proteins and lipoproteins in sheets. Later some regulatory genes arranged them into the classic double layers of cell membranes. Mitochondrial structures, a primitive organisms on their own who could metabolise with a Krebs Cycle, collided with and were engulfed by the membrane into the cytoplasm along with golgi. Bubbles of cell membrane became the transport vacuoles. This worked in some cells who learned to replicate these organelles. Remember mitochondria also have DNA? Is that coincidental?

I think this may be close to what we will eventually discover but for now it is just my hypothesis.

Fiach

Wounded King · 03-31-2003, 03:18 AM

Dear Fiach,

That last post sounds like a rather confused summary of the serial endosymbiosis hypothesis, the problem with that is that it is a theory to explain the origin of eukaryotic cells rather than abiogenesis.

I doubt that anyone would argue that the prokaryota were not alive but they lack the nuclei and mitochondria you seem to be placing into the context of abiogenesis.

thanks,

WK

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03-30-2003, 03:51 PM	#54
Principia Veteran Member Join Date: Mar 2002 Location: anywhere Posts: 1,976	Why, not chicken eggs at all. Let's all read what lucaspa had to say actually about the matter of Fox's protocells, here (this is lucaspa's take on the subject), and here (this is DNAunion's caricature of it, as he did above), rather than take DNAunion's word for it.

03-31-2003, 03:18 AM	#60
Wounded King Veteran Member Join Date: Mar 2003 Location: Edinburgh Posts: 1,211	Dear Fiach, That last post sounds like a rather confused summary of the serial endosymbiosis hypothesis, the problem with that is that it is a theory to explain the origin of eukaryotic cells rather than abiogenesis. I doubt that anyone would argue that the prokaryota were not alive but they lack the nuclei and mitochondria you seem to be placing into the context of abiogenesis. thanks, WK

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