Surely, evidence of everything alive (especially humans) supports Darwin's theory?

[scrappy]

I find it interesting how you keep ignoring my post which brought forth evidence in support of the abiogenesis hypotheses, information which I've now shared with you more than once.

I did respond to your post; it's in my post #36.

[iNow]

You're right. What I meant to say was that your response simply dismissed the data instead of addressing it.

[scrappy]

Which is a necessary precursor.

But, aside from the obviously needed chemicals, does anybody really know what the necessary precursors were that enabled abiogenesis?

 

So why are you adding *more* unknowns, without reason?

No, I'm questioning the assumptions you're making about what you claim to really know. I'm saying we don't know enough yet to get very far toward explaining abiogenesis.

 

You. Me. trees. Birds. Fungi. Every living thing is my evidence.

If that's all you need to believe in an Earthly abiogenesis then you don't require very much in the way of relevant facts.

 

Look, it's very, very simple - Occam's razor. The simplest theory that accounts for the data is most likely to be correct.

 

Geospermia - inorganic mess becomes complex chemicals becomes proto-life becomes life.

 

Panspermia - as above, plus a ride through space.

 

Panspermia involves an extra step, therefore is less likely.

 

In order to consider this extra step, there needs to be evidence which at the very least cannot be explained by the simpler theory. Just finding evidence that it *could* have happened is insufficient - lots of things *could* have happened, but didn't.

 

 

This goes to the very core of the scientific method, and is a basic precept. If you're going to cast it aside, you're doing pseudoscience.

Pseudoscience, ah? You're assuming that an Earthly abiogenesis is a better theory because it entails less complications, such as the need for space travel in the panspermia theory. OK, Occam's Razor may want to take a whack at that. But your theory is no less encumbered by whiskers, one of which is so geocentric as to be pre-Copernican. Specifically, that is the assumption that since life is already here it must have started here in the first place.

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You're right. What I meant to say was that your response simply dismissed the data instead of addressing it.

Hey, I'm fine with the bubble-making machines. Those protocells are really neat. But you need more than suds to make life from scratch, you need to come up with a digital language and an information storage and processing system, too.

Edited April 14, 2009 by scrappy
Consecutive posts merged.

[Mokele]

Look, it's really, very simple:

 

We know life originated, and that it exists on Earth. The simplest explanation is that the origin occurred on Earth, and at the moment, there's no data which indicates otherwise. It's also possible that life originated elsewhere and colonized Earth, but that requires an extra step, space travel. Ergo, it's most likely that life originated here.

 

This doesn't mean we *KNOW* life originated here, only that Earthly abiogenesis is the most plausible working hypothesis. If data comes to light that shows otherwise, then we change our minds. That's how science works.

 

It's not "geocentric", it simply minimizes assumptions.

 

Consider horse evolution - all of the relevant fossils occur in the US, from the Eocene onwards, with only spotty remains elsewhere (in spite of intensive efforts). The most plausible explanation is that horse evolution occurred in the US, with occasional migrants elsewhere. It's technically possible that it happened elsewhere, and we just haven't found the bones, but until we *do* find the bones, this is the most likely course of events.

 

Looking at earth first is nothing more than basic scientific principle. Nobody denies other possibilities, but possibilities without evidence are just speculations.

[scrappy]

You're right. What I meant to say was that your response simply dismissed the data instead of addressing it.

I have no quibble with nature's many ways of making fancy bubbles. You can call them "protocells" if you want to, but more than lipid membranes are needed to make a living cell. What more is there to address in the subject data?

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Look, it's really, very simple:

 

We know life originated, and that it exists on Earth. The simplest explanation is that the origin occurred on Earth, and at the moment, there's no data which indicates otherwise... If data comes to light that shows otherwise, then we change our minds. That's how science works.

Mokele, you and I are walking down a street and we stop in front of a house. You say, "scrappy, you see that red house there?"

 

I say, "Well, I see a house with its front side painted red. But I'd have to see all the sides painted red to call it a red house."

 

You say, "Oh, come one, now you're making things too difficult. It's a red house, anybody can see that."

 

I say, "Let's take a walk all the way around that house and then we'll see what color it really is."

 

You say, "Only a troll would dicker over such a silly matter. It's a red house, anybody can see that."

 

I say, "What's the harm in checking out that house more thoroughly. Maybe it's a green house, or white house with a red front. How can we know what color it is unless we look at all its sides?"

 

You say, "OK, scrappy, if you insist."

 

Moral: A scientist's job is NOT to accept anything at face value.

 

It's not "geocentric", it simply minimizes assumptions.

When it comes down to abiogenesis there are no minimal assumptions. As such, Occam's Razor is useless without a face for it to shave.

 

 

Consider horse evolution - all of the relevant fossils occur in the US, from the Eocene onwards, with only spotty remains elsewhere (in spite of intensive efforts). The most plausible explanation is that horse evolution occurred in the US, with occasional migrants elsewhere. It's technically possible that it happened elsewhere, and we just haven't found the bones, but until we *do* find the bones, this is the most likely course of events.

 

Looking at earth first is nothing more than basic scientific principle. Nobody denies other possibilities, but possibilities without evidence are just speculations.

But there is no evidence of an Earthly abiogenesis. The fact that life is here does not allow any more assumptions than that Earth is now bio-friendly. We simply do not know if Earth was also friendly to abiogenesis, simply because we do not know anything about how abiogenesis happened.

Edited April 15, 2009 by scrappy
Consecutive posts merged.

[lucaspa]

how is it debatable of the fact that we as life forms evolve without just random mutations but actually genetic differences to better fit there environment.

 

What you seem to be ignoring here is that selection is not random. Natural selection is a two step process:

1. Variation (mutations are one way to get variation)

2. Selection.

 

Variation is random in regard to the needs of the individual or population, but selection is not random. Only the variations that do well in that particular environment are selected.

 

things couldnt just be random like that. its alot like muscles, we need better ones, we develop better ones, we dont, we dont, right?

 

No, we don't. Here you are confusing the individual with the population. Evolution happens to populations, not individuals. We die with the same alleles we are born with. Our genetic makeup doesn't change during our lifetimes. So, if we need peak muscle strength beyond what we can genetically achieve, then no, we won't develop better muscles. You notice that no human can clean jerk 300 kg. Someone might "need" to do that in order to win the Olympic Gold in the sport, but he isn't going to develop the muscles to do so.

 

Now, if we were in an environment where people who could clean and jerk higher weights had a survival advantage, then eventually the population of humans would evolve to do so.

 

our different skin pigments? lighter skin, come from a snowier place, wich white reflects sun, and also blends in.

brown, from hotter places, like mexico, and alot of america, to not be as harmed by the sun by just getting darker instead of getting damaged.

black, well im sure they have a reason too. alright maybe thats not a good one to use for an example.

 

The evolutionary reason for skin color has been worked out, and it's not camoflauge. People in climates with snow can't survive without clothing, so skin color blending into snow has nothing to do with it. Instead, it involves vitamin B6 (folic acid) and vitamin D. UV light breaks down folic acid and deficiency in folic acid causes neural tube birth defects. So people in equatorial climates need lots of melanin in their skin (black) to protect their folic acid from UV radiation. However, UV light is needed to make vitamin D in the skin from cholesterol. So, as humans migrated north and got less UV radiation, really dark skin was disadvantageous because lack of vitamin D results in rickets. So, the further north (or south) from the equator, the lighter the skin as a balancing act to protect folic acid but let enough UV thru to make vitamin D. You can read more about it here: G Kirchwager, Black and white: the biology of skin color. Discover 22: 32-33, Feb. 2001.

 

but i just think that that sounds too far-fetched to belive that we are as we are by coincidence of gene abnormalities that just happen to be perfect for the environment we live in.

 

Not "perfect", but "better than the other guy". But yes, that's why we are as we are. We are designed by natural selection, not by direct manufacture by an intelligent entity.

 

When I say "better than the other guy", the design doesn't have to be "perfect", but just a bit better than the designs other people have. As the saying goes, you two of you are running from a bear, you don't have to be able to run faster than the bear, just faster than the other guy.

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I have no quibble with nature's many ways of making fancy bubbles. You can call them "protocells" if you want to, but more than lipid membranes are needed to make a living cell. What more is there to address in the subject data?

 

You don't need lipids to have a cell membrane. All you need are proteins. There is at least one way to get living cells from non-living chemicals. It's been done. Start at these websites (be sure to read them!) and we can discuss it further:

http://www.theharbinger.org/articles/rel_sci/fox.html

http://www.siu.edu/~protocell/

 

Bottom line: we have at least one way that, by chemistry, we can get the first life without it being manufactured.

 

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When it comes down to abiogenesis there are no minimal assumptions. As such, Occam's Razor is useless without a face for it to shave.

 

Ockham's Razor is useless in theory evalution anyway. The simplest theory is not necessarily the correct one. (BTW, what people call Ockham's Razor is, in reality, a principle formulated by Newton. Ockham described not a way to evaluate theories, but a way to describe phenomenon.)

 

But there is no evidence of an Earthly abiogenesis. The fact that life is here does not allow any more assumptions than that Earth is now bio-friendly. We simply do not know if Earth was also friendly to abiogenesis, simply because we do not know anything about how abiogenesis happened.

 

That last is simply not true. Read the websites. Protocells from thermal polymerization of amino acids has been shown to happen in a wide variety of conditions, all of which could have been present on the early Earth. For instance, protocells have been made in simulations of underwater thermal vents. Those are present now and would have been present on the early earth.

 

What's more, Fox and colleagues did simulated fossilization of the protocells and then compared those to fossils of the earliest life. They are identical.

The pictures are repoduced here: SW Fox, "Creationism and Evolutionary Protobiogenesis" in Science and Creationism ed. by Ashley Montagu, pp 194-239, 1982.

 

Sorry, but abiogenesis is not a "gap" that you can insert God into.

[Mokele]

I disagree - Ockham's razor doesn't say the simplest theory is correct, only that it's more likely to be correct (assuming both account for all data). And it's not only useful (as the primary driving force behind all phylogenies), but essential - without this supposition, there's no limit to the number of additional speculations that could be made.

 

If the theory is only "more likely to be correct", then how do you find out if it is correct? You are using it to eliminate theories that are more complex, but according to your own formulation, you can't do that! Because when you eliminate the theory (such as panspermia), you say that it is not correct at all. But, according to you, Ockham's Razor leaves it open that panspermia could be correct, just not as likely as abiogenesis.

 

Basically, Mokele, you have cut yourself off at the knees.

 

I can give you several examples (one of which I was personally involved in) where use of the Razor held science back.

 

It's basically saying that we shouldn't make more speculations than the data support.

 

Actually, what the Razor originally stated was that we should not add hypotheses onto the description of phenomenon. Ockham's original example was "objects move because of an impetus". Ockham realized that movement is change in position over time. Therefore the correct statement is "objects move". "because of an impetus" is a hypothesis to explain why the object moves. It's not needed.

 

In the present situation, the Ockham statement is "life exists on earth". Panspermia, abiogenesis, or special creation are all hypotheses to explain why live exists on earth. ALL of them are eliminated by the Razor.

 

Now, panspermia is actually eliminated by phylogenetic analysis. If panspermia is correct, it means that DNA is injected into life on earth that has no historical connection to the life that is already present. That's the essence of panspermia: life from outside earth. But phylogenetic analysis of DNA sequences shows that all DNA sequences are related by historical connections. That isn't possible if panspermia is true. So we can evaluate the validity of panspermia the only way theories are evaluated: by the data. In this case, panspermia is falsified.

Edited April 15, 2009 by lucaspa

[lucaspa]

Mokele, my sincere apologies. In replying to your post, I accidentally hit "edit" instead of "quote" and it replaced your post with my reply, under your name. The hazards of being a moderator without knowing all the mechanics involved. You will have to repost your reply to Scrappy, I'm afraid.

 

And my apologies to all the readers. The previous post is by Lucaspa, NOT Mokele. It's my response to Mokele.

 

((This is Mokele, I'm copying lucaspa's misplaced text below))

I disagree - Ockham's razor doesn't say the simplest theory is correct, only that it's more likely to be correct (assuming both account for all data). And it's not only useful (as the primary driving force behind all phylogenies), but essential - without this supposition, there's no limit to the number of additional speculations that could be made.

 

If the theory is only "more likely to be correct", then how do you find out if it is correct? You are using it to eliminate theories that are more complex, but according to your own formulation, you can't do that! Because when you eliminate the theory (such as panspermia), you say that it is not correct at all. But, according to you, Ockham's Razor leaves it open that panspermia could be correct, just not as likely as abiogenesis.

 

Basically, Mokele, you have cut yourself off at the knees.

 

I can give you several examples (one of which I was personally involved in) where use of the Razor held science back.

 

It's basically saying that we shouldn't make more speculations than the data support.

 

Actually, what the Razor originally stated was that we should not add hypotheses onto the description of phenomenon. Ockham's original example was "objects move because of an impetus". Ockham realized that movement is change in position over time. Therefore the correct statement is "objects move". "because of an impetus" is a hypothesis to explain why the object moves. It's not needed.

 

In the present situation, the Ockham statement is "life exists on earth". Panspermia, abiogenesis, or special creation are all hypotheses to explain why live exists on earth. ALL of them are eliminated by the Razor.

 

Now, panspermia is actually eliminated by phylogenetic analysis. If panspermia is correct, it means that DNA is injected into life on earth that has no historical connection to the life that is already present. That's the essence of panspermia: life from outside earth. But phylogenetic analysis of DNA sequences shows that all DNA sequences are related by historical connections. That isn't possible if panspermia is true. So we can evaluate the validity of panspermia the only way theories are evaluated: by the data. In this case, panspermia is falsified.

[Mokele]

I've placed your text back in this post, and I'll have to re-create my reply later, and reply to this. It might be a few days, though - I've got all-day animal surgery tomorrow.

[lucaspa]

I've placed your text back in this post, and I'll have to re-create my reply later, and reply to this. It might be a few days, though - I've got all-day animal surgery tomorrow.

 

Thanks. And no problem on the wait. I've got a paper to submit tomorrow. But since it's going to take you a while, consider this also before you reply.

 

In the second edition of Principia, Newton listed 4 "rules of reasoning in philosophy" Look at #1:

 

"We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearance". This, to me, sounds more like what you say is "Ockham's Razor" than what William of Ockham stated.

 

I will now quote from John Losee's A Historical Introduction to the Philosophy of Science, 4th edition, pg 83-84.

 

"In support of Rule 1, Newton appealed to a principle of parsimony, declaing that nature "affects not the pomp of superfluous causes". But exactly what Newton meant, or should have meant, by a "true cause" has beena subject of some debate. For instance, both William Whewell and John Stuart Mill criticized Newton for failing to specify criteria for the indentification of true causes. Whewell remarked that if Newton meant to restrict the "true cause" of a type of phenomnea to causes already known to be effective in producing other types of phenomena, then Rule 1 would be overly restrictive. It would preclude the introduction of new causes. However, Whewell was not certain that this was Newton's intended meaning. He noted that Newton may have meant only to restrict the introduction of causes to those of "similar in kind" to causes that previously have been established. Whewell observed that, thus interpreted, Rule 1 would be too vague to guide scientific inquiry. Any hypothetical cause could be claimed to display some similarity to previously established causes. Having dismissed these inadequate alternatives, Whewell suggested that what Newton should have meant by "true cause" is a cause represented in a theory, which theory is supported by inductive evidence acquired from analysis of diverse types of phenomenon.

Mill likewise interpreted "true cause" so as to reflect his own philosophical position. Consistent with his view of induction as a theory of proof of causal connection, Mill maintained that what disntinguishes a "true cause" is that its connection with the effect ascribed to it be susceptible to proof by independent evidence."

 

I would note that the term "sufficient" is being ignored by Losee. What generally accepted criteria do we have that a cause is "sufficient"? Within the limited area of being a material cause, we may have such criteria. But extended to a general idea of "sufficiency", there is a failure of consensus on criteria.

 

All in all, Rule 1 does not work as a means of theory evaluation. I would note that science has discarded Rule 3:

 

"In experimental philosophy we are to look upon propositions inferred by general induction from phenomena as accuarately or very nearly true, notwithstanding any contrary hypothesis that may be imagined, till such time as other phenomena occur, by which they may either be made more accurate, or liable to exceptions."

 

IOW, by Newton's rule, we can't falsify theories! Instead, data that contradicts them simply is viewed as exceptions to the theory.

[scrappy]

You don't need lipids to have a cell membrane. All you need are proteins.

But protein synthesis requires a lot of nucleic-acid transcription and translation of genetic code. You’d need a living cell with a genetic code, a transcription/translation system, and a few ribosomes to get the proteins you need. But you can get lipids from sea scum.

 

There is at least one way to get living cells from non-living chemicals. It's been done. Start at these websites (be sure to read them!) and we can discuss it further:

http://www.theharbinger.org/articles/rel_sci/fox.html

http://www.siu.edu/~protocell/

Sorry, lucaspa, but this is NOT the same thing as synthesizing life from scratch. Sure, you can make even a polio virus from mail-order genes; it's already been done. And Craig Venter's lab is now making artificial bacteria but stringing together the proper nucleotides to make a genome. He calls it ”digital life design”. But this is not in any way a duplication of abiogenesis.

 

Bottom line: we have at least one way that, by chemistry, we can get the first life without it being manufactured.

Well, yes, so long as you have a nice collection of spare nucleotides or mail-order genes. But I don’t call that “from scratch,” It’s from a “cake mix.”

 

Sorry, but abiogenesis is not a "gap" that you can insert God into.

I happen to be an untheist: one who believes that it doesn't matter if there is or isn't a god.

Edited April 15, 2009 by scrappy

[cameron marical]

you guys are right.i no longer believe that evelotion proceeds in the way i thought it did. i now know real science behind it.

 

Not "perfect", but "better than the other guy". But yes, that's why we are as we are. We are designed by natural selection, not by direct manufacture by an intelligent entity.

 

i never assumed or said that it was an intelligent entity making this, what i actually thought is that our brains actually had the ability to do things like stop growing facial hair in hot climates and others, and they just piled up to extremes as time progressed and generations changed.

 

like i said, i now know i was wrong. this post was kind of before i new much of biology{though im no expert at all now either what so ever} and was just getting into it.

 

 

thanks for all the replys guys, i have learned much from this post.

[lucaspa]

But protein synthesis requires a lot of nucleic-acid transcription and translation of genetic code. You’d need a living cell with a genetic code, a transcription/translation system, and a few ribosomes to get the proteins you need.

 

Directed protein synthesis in modern cells requires all this, but protein synthesis does not. You can get the proteins you "need" by thermal polymerization of amino acids. Once you have proteins, some of those proteins will synthesize other proteins as long as there are amino acids present (which you need for directed protein synthesis too).

 

Sorry, lucaspa, but this is NOT the same thing as synthesizing life from scratch.

 

Did you read the websites? Why isn't it abiogenesis? This isn't either of the examples you cited. You start with amino acids. Heat them dry or at a simulated hydrothermal vent. The heating causes the amino acids to polymerize to proteins. Then add water. The proteins spontaneously turn into cells. Those cells (called protocells):

1. Metabolize (both anabolism and catabolism)

2. Respond to stimuli (have action potentials like nerve cells)

3. Grow

4. Reproduce

 

Those are the 4 activities that define what is "alive". So, explain why this isn't abiogenesis. It's not a "nice collection of spare nucleotides or mail-order genes".

 

I happen to be an untheist: one who believes that it doesn't matter if there is or isn't a god.

 

ROFL! You just made that up, didn't you? Nobody but creationists argue so strongly against abiogenesis. According to you, it matters very much if there is a god. Without one, you claim there is no way to get life! So your whole arguments here contradict your own position as a non-theist!

[scrappy]

You don't need lipids to have a cell membrane. All you need are proteins. There is at leas tone way to get living cells from non-living chemicals. It's been done. Start at these websites (be sure to read them!) and we can discuss it further:

http://www.theharbinger.org/articles/rel_sci/fox.html http://www.siu.edu/~protocell/

You need to take a better look at what you’re saying. I don’t even know what you mean by “non-living chemicals.” Is RNA a non-living chemical? Is NaCl a non-living chemical? I’d say both are non-living chemicals' date=' including DNA. I’d like you to explain exactly what a “living chemical" is, please. And I’m not so impressed by your websites because they don’t address the need for genetically directed protein synthesis in living systems. If you know of a living system that gets along in life without genetic information I’d love to hear about it.

 

Directed protein synthesis in modern cells requires all this, but protein synthesis does not. You can get the proteins you "need" by thermal polymerization of amino acids. Once you have proteins, some of those proteins will synthesize other proteins as long as there are amino acids present (which you need for directed protein synthesis too).

OK, I’ll assume from what you say that the “needed” proteins can be made directly with AAs and heat. But that doesn’t get you abiogenesis from scratch. Of course, you can also get Directed protein synthesis by messenger ribonucleoprotein and ribosomes from different mammalian species, but you’d need a few live cells with ribosomes and mRNP. Where are you going to find those in your primordial soup before abiogenesis has occurred?

 

Did you read the websites? Why isn't it abiogenesis?This isn't either of the examples you cited. You start with amino acids. Heat them dry or at a simulated hydrothermal vent. The heating causes the amino acids to polymerize to proteins. Then add water. The proteins spontaneously turn into cells. Those cells (called protocells):

1. Metabolize (both anabolism and catabolism)

2. Respond to stimuli (have action potentials like nerve cells)

3. Grow

4. Reproduce

Reproduce what? You’ve haven’t even addressed the need for the emergence of a digital genetic code. Do you think that genetic code just comes along like magic? You cannot have abiogenesis until you have a cell with the ability to pass on its genetic material to its progeny. Just making “protocells” and filling them with proteins won’t get the job done.

 

Bottom line: we have at least one way that, by chemistry, we can get the first life without it being manufactured.

I’m astonished that one in your position would say this. If what you say is true then please show the evidence that those little gene-less critters actually did pop out as the “bottom line.”

 

Those are the 4 activities that define what is "alive". So, explain why this isn't abiogenesis. It's not a "nice collection of spare nucleotides or mail-order genes".

I’m still wondering how you can get “reproduction” in life without being concerned about genetic inheritance. Do your “protocells” just sort get their genetic information by osmosis? No, that wouldn’t work in abiogenesis because there would be no ambient genetic information to absorb. All your meaty little “protocells” can do is play like prions, and that won’t get them much more than a fatal disease.

 

I happen to be an untheist: one who believes that it doesn't matter if there is or isn't a god.

ROFL! You just made that up, didn't you? Nobody but creationists argue so strongly against abiogenesis. According to you, it matters very much if there is a god. Without one, you claim there is no way to get life! So your whole arguments here contradict your own position as a non-theist!

This statement is unbecoming of a “Biology Expert Moderator.” How can you refute my claim of being an untheist? Who would know better than I? Suggesting that I am a creationist is shameful, worthy of suspension. This is just more evidence that you are insecure about your position in this debate.

[Mr Skeptic]

Did you read the websites? Why isn't it abiogenesis? This isn't either of the examples you cited. You start with amino acids. Heat them dry or at a simulated hydrothermal vent. The heating causes the amino acids to polymerize to proteins. Then add water. The proteins spontaneously turn into cells. Those cells (called protocells):

1. Metabolize (both anabolism and catabolism)

2. Respond to stimuli (have action potentials like nerve cells)

3. Grow

4. Reproduce

 

Those are the 4 activities that define what is "alive". So, explain why this isn't abiogenesis. It's not a "nice collection of spare nucleotides or mail-order genes".

 

Could you send me one of these living protocells and a list of their nutritional requirements? I'd like to grow my own colony of them from one of yours.

[Kyrisch]

Reproduce what? You’ve haven’t even addressed the need for the emergence of a digital genetic code. Do you think that genetic code just comes along like magic? You cannot have abiogenesis until you have a cell with the ability to pass on its genetic material to its progeny. Just making “protocells” and filling them with proteins won’t get the job done.

 

Look, I've pointed this out at least twice before. The role of 'genetic material' as a 'code' for protein synthesis only came about after the protobionts started 'replicating' through normal lipid interactions. The genetic material of protobionts were just simple self-replicating molecules that were lucky enough to find themselves inside a protected lipid layer. The nucleic-amino acid relationships developed AFTER these protobionts had been around for awhile. There is no issue here.

[scrappy]

Look, I've pointed this out at least twice before. The role of 'genetic material' as a 'code' for protein synthesis only came about after the protobionts started 'replicating' through normal lipid interactions. The genetic material of protobionts were just simple self-replicating molecules that were lucky enough to find themselves inside a protected lipid layer. The nucleic-amino acid relationships developed AFTER these protobionts had been around for awhile. There is no issue here.

Well, there is one issue here: Are you stating fact or theory or what? There is no commonly agreed-upon theory that "the role of 'genetic material' as a 'code' for protein synthesis only came about after the protobionts started 'replicating' through normal lipid interactions." That is just one of many hypotheses about abiogenesis that lacks any kind of empirical evidence to support it. Aren't you being just a little naive about the mysterious formation of a digit genetic language? Nothing in your theory accounts for that.

[Kyrisch]

Well, there is one issue here: Are you stating fact or theory or what? There is no commonly agreed-upon theory that "the role of 'genetic material' as a 'code' for protein synthesis only came about after the protobionts started 'replicating' through normal lipid interactions." That is just one of many hypotheses about abiogenesis that lacks any kind of empirical evidence to support it. Aren't you being just a little naive about the mysterious formation of a digit genetic language? Nothing in your theory accounts for that.

 

You're misunderstanding me. You are hung up on the "mysterious formation" of the genetic material as being code. The thing I was trying to point out was that the nucleic-amino acid relationship need not arise until after the protobionts were many in number and the full force of natural selection was acting on them. Abiogenesis concerns itself with the first self-replicating molecule that was able to pull it off before being destroyed, and nothing more than that. All the intricacies of modern cells were absent in protobionts. Most theories describe them as some stray nucleic acid in a lipid bubble.

[scrappy]

You're misunderstanding me. You are hung up on the "mysterious formation" of the genetic material as being code. The thing I was trying to point out was that the nucleic-amino acid relationship need not arise until after the protobionts were many in number and the full force of natural selection was acting on them. Abiogenesis concerns itself with the first self-replicating molecule that was able to pull it off before being destroyed, and nothing more than that. All the intricacies of modern cells were absent in protobionts. Most theories describe them as some stray nucleic acid in a lipid bubble.

Thank you for pointing out my hang ups. And you are quite right: I am terribly hung up about the need for a digital genetic code to arise (however mysteriously) in the course of any abiogenesis event. If you don’t recognize that simple and obvious fact then we may not have enough common ground to stand on for a debate.

 

Abiogenesis requires more than the propagation of chemical analogues in a fatty bubble; it requires also the propagation of coded instructions for the maintenance and development of whatever proto-organism has emerged. You cannot simply dismiss this part of abogenesis as perfunctory.

 

Your little “prebionts” in their lipid bubbles, how do they accomplish reproduction without a genetic language? Just simply duplicating themselves in chemical composition is not enough; calcite crystals can do that. What makes abiogenesis so important is that the direct progeny of that special event carried along coded instructions on the development of the progeny’s chemical analogues.

[Kyrisch]

Abiogenesis requires more than the propagation of chemical analogues in a fatty bubble; it requires also the propagation of coded instructions for the maintenance and development of whatever proto-organism has emerged. You cannot simply dismiss this part of abogenesis as perfunctory.

 

Yes, I can, because that all came about through evolution. As soon as you have an (imperfectly) self-replicating entity, evolution begins -- even without genes! You see, the chemical identity of the genetic material itself could have strengthened or weakened the lipid bubble through electromagnetic interactions. Soon, instead of more nucleic acids linking up in correspondence to the existing genetic material, an amino acid finds its way. A crude, simple, entirely random protein is formed. Whether or not this protein helps will determine whether or not that length of code is propagated more or less than any other.

 

Have you taken biology? The same way that the base pairs are attracted to each other, specific amino acids are attracted to specific base pairs, too. This is how the 'digital code' came about. It was a natural consequence of the interaction between nucleic and amino acids.

[Mr Skeptic]

I don't think anyone has demonstrated that DNA or RNA are necessary for reproduction. Certainly for current life they are. But it might be possible for proteins to assemble copies of themselves, even if imperfect copies.

[scrappy]

Have you taken biology? The same way that the base pairs are attracted to each other, specific amino acids are attracted to specific base pairs, too. This is how the 'digital code' came about. It was a natural consequence of the interaction between nucleic and amino acids.

Yes, I’ve taken biology. I have a Ph.D. in biology. Anyway, you say base pairs are “attracted to each other”? I never learned about any such "attractions" in the chemistry courses I ever took. You’re seeing protein synthesis as entirely tinkertoy chemistry; as such, in your eyes, all reactions are sterochemical. I think you’re viewing genetic transcription and ribosomal translation as if they were stereochemical all the way from codons to amino acids.

 

So, I might ask you if you have every read the crucial paper by F. H. C. Crick, “The Origin of the Genetic Code” (1968, J. Mol. Biol., pp. 367-379). If you had you would see why proponents of the stereochemical theory face “grave difficulties”:

 

The point of this sketch is to impress the reader with the great difficulty of the problem. It would certainly be easier if specific stereochemical interactions could occur between amino acids and triplets of bases, but even if these are possible the origin of the present ribosomal translation mechanism presents grave difficulties.

If you could get a copy of this paper through your public library (I don't know of an Internet source) and read it carefully, you would see why the origin of the genetic code is not so easily dismissed as perfunctory.

[Kyrisch]

Yes, I’ve taken biology. I have a Ph.D. in biology. Anyway, you say base pairs are “attracted to each other”? I never learned about any such "attractions" in the chemistry courses I ever took. You’re seeing protein synthesis as entirely tinkertoy chemistry; as such, in your eyes, all reactions are sterochemical. I think you’re viewing genetic transcription and ribosomal translation as if they were stereochemical all the way from codons to amino acids.

 

So, I might ask you if you have every read the crucial paper by F. H. C. Crick, “The Origin of the Genetic Code” (1968, J. Mol. Biol., pp. 367-379). If you had you would see why proponents of the stereochemical theory face “grave difficulties”:

 

 

If you could get a copy of this paper through your public library (I don't know of an Internet source) and read it carefully, you would see why the origin of the genetic code is not so easily dismissed as perfunctory.

 

I'm sorry if I insulted your intelligence, and I'm sorry if I'm greatly simplifying the issue. Unfortunately though, a lack of imagination is not enough to dismiss a theory. Just because we have little knowledge how one specific component might work, if the evidence is consistent with the rest of the theory, and more importantly, if we have no other working theory, one can't just dismiss it based on incredulity alone.

[lucaspa]

Could you send me one of these living protocells and a list of their nutritional requirements? I'd like to grow my own colony of them from one of yours.

 

You can make your own. It's very simple. Here's the recipe:

Call Sigma Chemical Co. at 800-325-3010 and order 1 bottle of catalog number M 7145 and one bottle of R 7131 amino acids solutions (you need both to get all the amino acids http://www.sigmaaldrich.com/sigma/formulation/M5550for.pdf ). They will cost you about $40 plus shipping for both. Empty the bottles into a fying pan, turn the heat on low and heat until all the water is evaporated. Then heat for 20 more minutes. Add water.

 

You can then add more amino acids, some ATP, and some sugars if you want. However, it turns out that some of the protocells are photosynthetic.

 

You are going to have a minor problem: bacterial contamination. Bacteria are everywhere and, if you leave the protocell solution sitting out for even a couple of minutes, bacteria from the air, your spoon, etc, is going to get into the solution and these bacteria will, in about a day, eat the protocells. So, do you have a laminar flow hood and some culture dishes?

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Yes, I’ve taken biology. I have a Ph.D. in biology. Anyway, you say base pairs are “attracted to each other”? I never learned about any such "attractions" in the chemistry courses I ever took.

 

Then you don't have a Ph.D. in biology! Any Ph.D. would immediately recognize the phrase "attractions" to mean the hydrogen bonding between complementary bases.

 

So, I might ask you if you have every read the crucial paper by F. H. C. Crick, “The Origin of the Genetic Code” (1968, J. Mol. Biol., pp. 367-379). If you had you would see why proponents of the stereochemical theory face “grave difficulties”:

 

 

If you could get a copy of this paper through your public library (I don't know of an Internet source) and read it carefully, you would see why the origin of the genetic code is not so easily dismissed as perfunctory.

 

The public library will not have a copy of the paper. But notice that the paper is 1968. Here are some more recent papers for you to read that show how the genetic code can easily have evolved:

 

1. Alberti, S The origin of the genetic code and protein synthesis. J. Mol. Evol. 45: 352-358, 1997.

1. 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.

2. P S Schimmel 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.

3. http://compbiol.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pcbi.0030139 Paper showing evolution of stable proteins.

4. Margaret E. Saks, Jeffrey R. Sampson, John Abelson Evolution of a transfer RNA gene through a point mutation in the anticodon. Science, 279, Number 5357 Issue of 13 March 1998, pp. 1665 - 1670

[Mokele]

I don't have much time for a full reply, so I'll post this briefly:

 

Yes, abiogenesis is not "easy", and there are several steps that we don't fully understand. What does this have to do with panspermia? Whether on Earth or elsewhere, Crick's difficulties still apply. DNA, tRNA, ribosomes, codons, etc. still had to develop, even on another world. How does a change in temperature, oxygen level, or ocean salinity solve this?

 

Furthermore, I don't think panspermia helps as much as you'd think. It expands the parameters, but only within a range such that the extraterrestrial life could live on early Earth. That means generally similar temperatures (nothing that needs -100C or +200C environments), similar chemical access (doesn't require things that are super-rare on Earth, isn't poisoned by common Earth chemicals), similar environment (no methane oceans or boiling lead), etc. Given that early Earth wasn't a homogenous mass, you could probably find some or many of the 'extraterrestrial' conditions here, such as under ice or near deep-sea vents.

 

So how useful is it, really? What does it offer?