Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 157 (8161 total)
Current session began: 
Page Loaded: 11-23-2014 4:41 AM
45 online now:
Mr Jack, PaulK, Tangle (3 members, 42 visitors)
Chatting now:  Chat room empty
Newest Member: NAME OF THE ROSE
Post Volume:
Total: 741,706 Year: 27,547/28,606 Month: 2,604/2,244 Week: 8/710 Day: 8/129 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
1
23456Next
Author Topic:   Abiogenesis - Or Better Living Through Chemistry
Quetzal
Member (Idle past 2368 days)
Posts: 3228
Joined: 01-09-2002


(1)
Message 1 of 85 (5654)
02-27-2002 4:57 AM


Apologies in advance for the length of this post. Enjoy!

Even though abiogenesis – the origin of life from non-life – is not related to the validity or falsehood of evolutionary theory, it is an interesting subject in its own right. Although evolutionary theory does not rest on the truth of abiogenesis, creationists in particular seem to demand that a non-supernatural origin of life be “proven” before evolution can be accepted. It is in that sense that I will undertake to provide a brief synopsis of the various hypotheses, and discuss in general terms both the positive aspects and the potential problems with each. Consider this the “Reader’s Digest Condensed Version” of abiogenesis.

The discussion of the origin of life is one of the most complex and contentious issues in science today. Because the issue is so complex, there are many, including even some scientists (almost all from outside the biological sciences), who claim that it was, in fact, impossible for life to have arisen through solely natural processes. They believe there was required some Divine Spark, or Supreme Designer, standing outside all known universal laws to initiate the process. Finally, they believe that life contains some level of organization below which recourse to merely physical laws cannot explain how it came into being – a First Event from which all else flows.

Although our knowledge in some areas may be weak or we may be missing some details today, natural abiogenesis studies begin with the premise that there is nothing unknowable in nature. Life, in the final analysis, makes perfect sense using known physical laws. The actions of a Supreme Being are not required to explain it. Reason, analogies drawn from modern organisms, and the results of scientific research from disciplines as diverse as astronomy, astrophysics, microbiology, parasitology, chemistry, biology, genetics and geology, as well as dozens of others, provide sufficient explanation. There was no First Event.

There are currently three main scientific hypotheses for how life arose on Earth. All three have their adherents, and all three are actively being researched by some of the finest scientific minds on the planet. All three have both empirical and inferential support (for elements of the theory), but all three contain certain assumptions that must be true for the theory to be valid. All three contain elements that have been shown either in the lab or in nature to lend credence to their hypothesis.

There is one unifying thread that ties all three hypotheses together which must be understood at the outset: all three hypotheses rest on a foundation of organic chemistry. Don’t get confused. “Organic” here does not mean “living” or “coming from life”. Organic chemistry is nothing more than the chemistry of carbon. It happens to be enormously richer than the chemistry of other elements - and thus able to support life - because of the unique associative properties of the carbon atom. In all likelihood the first building blocks of life arose as do all natural chemical compounds - spontaneously, according to the rules of thermodynamics. In one way of looking at it: we ARE carbon.

1. The Biotic Soup Hypothesis

This is arguably the most well-known (and least understood!) hypothesis. In essence, the hypothesis argues that chemicals available on the Hadean Earth from either terrestrial or extraterrestrial sources combined via standard chemical reactions to form biologically significant macromolecules. The biotic soup hypothesis uses an ammonia-methane atmosphere as a starting point, and naturally occurring electrical storms and radioactivity as the energy source.

Spectroscopic analysis by astronomers has revealed that space is permeated by an extremely tenuous cloud of microscopic particles, called interstellar dust, containing a variety of combinations of carbon, hydrogen, oxygen, nitrogen and, sometimes, sulfur or silicon. These are mostly highly reactive free atoms and small molecules that would hardly remain intact under conditions on earth, but in space could interact to form more stable, typical organic compounds, many of them similar to substances found in living organisms. That such processes indeed take place is demonstrated by the presence of amino acids and other biologically significant compounds on celestial bodies – for example, the meteorite that fell in 1969 in Murchison, Australia, Comet Halley (which was analyzed by the Giotto spacecraft during its 1985 passage), and Saturn's satellite Titan, the seas of which are believed to be made of hydrocarbons (based on the Voyager fly-bys) and which contains an atmosphere with significant organic compounds.

The modern chemical composition of the Earth is mostly Fe, Mg, Si, and O, with the other elements contributing 5% of the total. Life originated as a result of chemical reactions occurring (largely) in the atmosphere followed by reactions in the primeval oceans and lakes. The atmosphere at the end of the Hadean Period (~4-4.2 gya) is primarily composed of variable amounts of CO2, N2, SO2, H2S, S, HCl, B2O3, and smaller quantities of H2, CH4, SO3, NH3 and HF (but no O2), due partly to outgassing from volcanoes, and partly to the reaction of condensing water vapor (formed as the Earth cooled) with minerals such as nitrides (hence NH3), carbides (hence CH4, CO, etc.) and sulfides (hence H2S). There was no free oxygen (any free O2 would have reacted with P, Si and metals such as molten iron to give minerals e.g. iron oxides, silicates, phosphates, etc.). This atmosphere readily lends itself to the formation of small organic molecules, which in turn readily combine to form more complex macromolecules.

In the lab, tantalizing experiments attempting to re-produce the atmospheric conditions of the early Earth have produced astonishing results. As early as the 1950’s Harold Urey used simple electrical stimulation of a hydrogen-methane-ammonia atmosphere and – in just a few days – saw over 15% of the methane/carbon converted to amino acids: one of the key building blocks of proteins and hence life. Although his postulated atmosphere was probably inaccurate, the same amino acids in nearly the same proportions have been discovered in the Murchison asteroid. Since Urey, besides amino acids and other organic acids, experiments have yielded complex sugars as well as purine and pyrimidine bases, and even adenine: some of the components of the nucleic acids DNA and RNA, the genetic repositories of the codes of all life. Stanley Miller is STILL working on the problem at UC San Diego.

There are a few problems with this hypothesis. In the first place, it is impossible at this remove to determine the exact chemical composition of the early atmosphere – hence whereas the chemical reactions are quite straightforward, the relative yield is open to interpretation. In addition, many of the small organic molecule precursors such as HCN and HCHO are volatile and would break down readily in the atmosphere. It is postulated that these precursors were absorbed into the primeval ocean where they would be shielded from the damaging UV (<300 nm), creating the “organic soup” of the Urey-Miller experiments.

2. Cairns-Smith Crystal Matrix Hypothesis

One of the problems with the biotic soup hypothesis, even assuming the chemical reactions were as stated, is how these macromolecules – randomly distributed as they were – were able spontaneously to form the key biological macromolecules such as peptides and nucleic acids. The probability of the formation of these crucial biological molecules from a random mixture of organic chemicals is vanishingly small. In addition, these molecules had to be self-replicating. The chemist Alexander Cairns-Smith proposed that inorganic materials, rather than organic, represented the first replicators.

The fundamental problem he was trying to address is the requirement that the first "life" (using the term very loosely) had to have been self-replicating. Cairns-Smith speculated that the earliest replicators were not organic at all, but rather were self-replicating crystals that were later superseded by the rise of the far-more-efficient organic replicators. In this view, the first replicators were crystals of the type that exist in clay or mud along riverbanks; they transmitted their "genetic" information through the natural tendency of these types of molecules to fit together into a geometric pattern.

The fundamental characteristic of crystals as replicators must be hereditary variation, or inheritance. Fortunately, crystals in nature display this pattern: they may be perfectly aligned until a specific point is reached, in which a flaw has accumulated (these are quite common in natural crystals). This flaw has a tendency to percolate down the subsequent layers of crystal, setting up a rudimentary system of heredity. Furthermore, atoms of the crystal's substance may be more attracted to certain geometric patterns than they are to others. This sets up a kind of "differential reproduction" which then leads logically to a form of natural selection.

The hypothetical crystals described above may very well begin a basic process of cumulative selection. Certain crystals may have the property of altering streams or other water sources for their own "benefit", such as by increasing the likelihood of more of the same material being deposited in the same location. Crystals may also encourage the formation of "spores" by breaking easily into subsequent "generations" Those crystals that broke into generations most easily would be selected for; these generations would invariably contain mutations on occasion and would intensify the competition between rival variants.

In time, the crystals could evolve a sort of "phenotype" by altering other materials in their environment. These materials could be used to further the crystal's replication by inhibiting rival crystals from forming or promoting the parent crystal's reproduction. Cairns-Smith's hypothesis is that the materials used by the crystals for self-replication later turned out to be even more efficient replicators in their own right – the earliest peptide-RNA – which ultimately replaced their inorganic substrates. This process of replacement might repeat for several cycles, or the first products used by the crystals may have been the ancestors of modern replicators - i.e., RNA and eventually DNA.

The principal difficulty with Cairns-Smith’s hypothesis is the fact that clay doesn't necessarily form a lattice/matrix that is perfectly designed for the arrangement of biologically significant molecules. Since there are a rather large number of potential arrangements, getting the precise arrangement necessary to act as a catalyst for a specific molecule is pretty problematic. Finally, the type of clays best suited for this type of “inorganic evolution” are usually found in riparian zones – the smaller biological molecules are fairly unstable when subjected to unshielded UV. It remains to be seen whether such processes could occur in such a way that these molecules could persist long enough to form stable compounds.

However, as with Miller, Cairns-Smith’s organic replicator overthrow of the inorganics only needed to occur once…

3.a. Submarine Hot Springs Hypothesis – Electrochemical Variant

In this hypothesis, life is believed to have begun at the sites of warm submarine springs where chemical energy was focused and the mixing of spring water with seawater could lead to the precipitation of chemicals. The precipitation of chemicals on mixing of solutions can form a barrier preventing further mixing and precipitation. This barrier can also provide a template for the assembly of chains of organic molecules, and act as a catalyst for electrochemical reactions. This hypothetical precipitate, again operating in a naturally occurring biotic soup, consisted mainly of small groups of iron and sulfur atoms. Iron-sulfur groups still play an essential electrochemical catalytic role in all living cells.

As a boundary, the precipitate concentrated organic molecules such as amino acids. These formed at depth below the spring where water and its dissolved chemicals reacted with rocks containing Fe and iron-rich minerals. The boundary also concentrated other chemicals that could participate in chemical reactions.

As a catalyst the groups of FeSiO4 and Fe3O4 could activate molecular hydrogen (and probably methane which consists of carbon and hydrogen) which also formed at depth in the spring. The hydrogen is essential for the synthesis of organic molecules. Electrons produced as a by-product (and representing the dissipation of energy) are transferred to a type of iron, known as ferric iron, dissolved in seawater. (The ferric iron is produced from dissolved ferrous iron (richer in electrons) at the ocean's surface by sunlight. The same processes cause the reddening of the surface of Mars as iron-bearing minerals have “rusted”.

As a template, the iron sulfide precipitate (consisting of small crystals of only a hundred atoms or so), could bond chemically to, and assemble a sequence of, the molecular components of RNA. Acid springs of high temperature, coupled to emergent magma plumes, emit ferrous iron and other transition metals to the ocean. Solar energy oxidizes some iron to the ferric state, generating a dispersed positive terminal. Cooler alkaline waters emanate from the deep ocean floor, bearing hydrogen, methane, ammonia, formaldehyde, cyanide and hydrosulfide - molecules reduced from water and carbon oxides by reaction with ferrous silicate, residual nickeliferous iron and ferrous sulfide. Where these waters seep into the ocean, mounds, comprising layers of ferrous sulfide and green rust flocculants and films, arise. These mounds are where the reduced molecules are filtered and adsorbed. Concentrated, they react to form glyceraldehyde, amino acids, and the components of nucleosides.

The fluids are prevented from mixing thoroughly with the surrounding ocean by the spontaneous precipitation of a barrier of colloidal iron compounds. Nucleotides can then assemble in green rust. The thermal potential begins to be dissipated but the chemical potential is dammed. Though the hydrothermal solution is constrained, electrons escape from adsorbed hydrogen through the conducting layers of iron monosulfide, drawn to reduce the photolytic ferric iron.

There is invasion of the iron sulfide/hydroxide barrier by protons, pyrophosphate and carbonic acid, through iron sulfide-walled micro-channels. The newly formed nucleotides poison the iron sulfide but combine with peptides, producing pRNA. The side chains of particular amino acids register to fitting nucleotide triplet clefts. Keyed in, the amino acids are polymerized, through acid-base catalysis, to alpha chains by invading protons. The resulting short protopeptides sequester ready-made iron sulfide clusters to form ferredoxins, ubiquitous proteins with the longest evolutionary pedigree. These take over the role of catalyst and electron transfer agent from the iron sulfides, promote further chemosynthesis and so support the electrochemical reactor from which they sprang.

The principal problem with this hypothesis is the reliability of the invasion and precipitation scenario. To wit, how effective is the sulfide barrier and the green rust substrate at providing a template for biological macromolecules? In addition, to be more plausible, the hypothesis must assume a fairly high concentration of chemical precursors. Especially since, unlike the evaporation-concentration element of Miller’s biotic soup hypothesis, there is no specific mechanism for concentrating these molecules into sufficiently close proximity for the electrochemical bonding to take place.

3.b. Submarine Hotsprings Hypothesis – Flow Reactor Variant

Similar to the above, however instead of a postulated electrochemical mound as one of the poles, this theory using the high-temperature (300-400 C) energy found in the cracking front of submarine steam vents (“black smokers”) to provide the necessary energy.

In a hot spring, the flow of heat is constrained by the structure and constitutive properties of magma, rock and water; the gravity field, etc. The model proposes that in addition to the coherent flow of fluid, these constraints produce phase space trajectories which lead to the creation of high-energy molecular and macromolecular structures in which the particles are locked, or frozen, into coherence. The cooling particles fall and are trapped into the potential energy wells, i.e. attractors, provided by the constraining forces that bind matter together. In other words, life is an emergent property of the high-temperature chemistry and physical constraints present in the flow reactor of a submarine magma pipe.

The products of rapid heating and quenching at the cracking front follow a highly constrained trajectory, rapidly mixing with cool sea water flowing upward through a matrix of fractured rocks of enormous surface area, lined with a highly catalytic surface of clay minerals (note the use of Cairns-Smith’s clay matrix). They began their ascent as hot (~350° - 600°C), acid (pH~3.6), highly reducing fluids, and approach a low temperature end member which is cold (~2° - 20°C), slightly alkaline (pH 7.9), and oxidizing. A fraction of the thermal energy traveling from mantle to ocean is trapped into the high energy bonds of organic molecules, which remain as static equilibrium structures. The process is thermodynamically analogous to the emergence of matter from energy during the expansion and cooling of the early Universe.

As with the other hypotheses, this one also relies on the presence of organic molecules in the primeval ocean. However, unlike the biotic soup idea, these precursor molecules would be concentrated by the geophysical properties of the mantle at the site of the hotsprings.

Conclusion

Regardless of which of the above hypotheses ultimately leads to the creation of self-sustaining biomolecules, all show that life is merely an inherent property of chemical reactions. Any time conditions are appropriate, life (as we know it) should arise. And once we get self-replicating molecules, evolution (heritable variation, random mutation, and natural selection) + time are sufficient to explain the amazing diversity of modern life.

Science has yet to provide evidence for any of these hypotheses beyond reasonable doubt. But since all are “brand new” ideas, the only thing lacking is time… Stay tuned!


Replies to this message:
 Message 2 by joz, posted 02-27-2002 10:55 AM Quetzal has responded
 Message 3 by John Paul, posted 02-27-2002 5:25 PM Quetzal has responded
 Message 37 by Brad McFall, posted 04-01-2002 1:45 PM Quetzal has not yet responded
 Message 38 by Andor, posted 06-03-2002 10:15 AM Quetzal has responded
 Message 43 by Bart007, posted 09-07-2002 8:31 PM Quetzal has responded

  
joz
Inactive Member


Message 2 of 85 (5692)
02-27-2002 10:55 AM
Reply to: Message 1 by Quetzal
02-27-2002 4:57 AM


Great post Quetzal, thanx.....

Q)I was under the impression that one of the problems with The Biotic Soup Hypothesis of abogenesis was the low abundance of sugars produced and the lack of long chain fatty acids (in the Urey/Miller experiments). Has anything new cropped up that makes this less of a problem?


This message is a reply to:
 Message 1 by Quetzal, posted 02-27-2002 4:57 AM Quetzal has responded

Replies to this message:
 Message 26 by Quetzal, posted 03-01-2002 3:00 AM joz has responded

  
John Paul
Inactive Member


Message 3 of 85 (5727)
02-27-2002 5:25 PM
Reply to: Message 1 by Quetzal
02-27-2002 4:57 AM


quote:
Quetzal:
Conclusion

Regardless of which of the above hypotheses ultimately leads to the creation of self-sustaining biomolecules, all show that life is merely an inherent property of chemical reactions. Any time conditions are appropriate, life (as we know it) should arise. And once we get self-replicating molecules, evolution (heritable variation, random mutation, and natural selection) + time are sufficient to explain the amazing diversity of modern life.

Science has yet to provide evidence for any of these hypotheses beyond reasonable doubt. But since all are “brand new” ideas, the only thing lacking is time… Stay tuned!


John Paul:

quote:

It was concluded in the 1960s that the earth's primitive atmosphere was derived from volcanic outgassing, and consisted of water vapor, carbon dioxide, nitrogen and trace amounts of hydrogen. With most of the hydrogen being lost to space, there would be nothing to reduce the carbon dioxide and nitrogen, so methane and ammonia could not have been major constituents of the early atmosphere.

The only reason people cling to the reducing atmosphere hypothesis is because it offers the best hope. The rocks don't substantiate that claim though.

We also have no evidence that DNA can form anywhere outside of a living cell, and the cell itself represents IC (irreducible complexity):

Unraveling the DNA Myth

It looks like only life can beget life.

The thing is, these days we can take and mix amino acids at will and in differing environments. Guess what? Nothing resembling the start of life, just a bunch of stirred up amino acids in a flask.

Life isn't just about chemical reactions. How long is it going to take before you realize that?

Approaching Biology from a Different Angle

I do find this all interesting and I hope the research continues, privately funded of course. Proving all these purely natural scenarios (for the origins of life) may be the only way to get people focused on how we really got here.

------------------
John Paul


This message is a reply to:
 Message 1 by Quetzal, posted 02-27-2002 4:57 AM Quetzal has responded

Replies to this message:
 Message 4 by TrueCreation, posted 02-27-2002 6:30 PM John Paul has responded
 Message 6 by mark24, posted 02-27-2002 7:41 PM John Paul has responded
 Message 27 by Quetzal, posted 03-01-2002 3:33 AM John Paul has not yet responded
 Message 28 by Quetzal, posted 03-01-2002 3:49 AM John Paul has not yet responded

  
TrueCreation
Inactive Member


Message 4 of 85 (5733)
02-27-2002 6:30 PM
Reply to: Message 3 by John Paul
02-27-2002 5:25 PM


--Thought I would reply to this bit that caught my eye, by the way, did you write all of that, or is it an outside article?

"It was concluded in the 1960s that the earth's primitive atmosphere was derived from volcanic outgassing, and consisted of water vapor, carbon dioxide, nitrogen and trace amounts of hydrogen. With most of the hydrogen being lost to space, there would be nothing to reduce the carbon dioxide and nitrogen, so methane and ammonia could not have been major constituents of the early atmosphere."
--I found it as a bit of a 'possible', inconsistancy with the process of geologic and volcanic cycles within marine geology. Knowing this cycle, gases being volatiles are I believe produced as a consequence of subduction, a basic plate-tectonic phenomenon. Being of such an origin, I would wonder what came first, the atmosphere, or the oceans? Seeing that this process is what it seems is required for an atmosphere to be created, thereby requireing an ocean. Or am I wrong on gases in the earths asthenospheric mantle. Also, if this is the process that is required for gases to be an origination from volcano's, the genesis of the earth itself in the Solar system's evolution may be flawed. That is, the theory that the Earth was once a molten mass. If the earth ever was a liquid molten mass, gasses would easilly escape out of the earth, viscosity being of a much higher magnitude. Anyways, this is just a thought.

-------------------


This message is a reply to:
 Message 3 by John Paul, posted 02-27-2002 5:25 PM John Paul has responded

Replies to this message:
 Message 5 by John Paul, posted 02-27-2002 7:02 PM TrueCreation has responded
 Message 24 by joz, posted 02-28-2002 11:45 AM TrueCreation has not yet responded

  
John Paul
Inactive Member


Message 5 of 85 (5734)
02-27-2002 7:02 PM
Reply to: Message 4 by TrueCreation
02-27-2002 6:30 PM


quote:
Originally posted by TrueCreation:
--Thought I would reply to this bit that caught my eye, by the way, did you write all of that, or is it an outside article?

"It was concluded in the 1960s that the earth's primitive atmosphere was derived from volcanic outgassing, and consisted of water vapor, carbon dioxide, nitrogen and trace amounts of hydrogen. With most of the hydrogen being lost to space, there would be nothing to reduce the carbon dioxide and nitrogen, so methane and ammonia could not have been major constituents of the early atmosphere."

--I found it as a bit of a 'possible', inconsistancy with the process of geologic and volcanic cycles within marine geology. Knowing this cycle, gases being volatiles are I believe produced as a consequence of subduction, a basic plate-tectonic phenomenon. Being of such an origin, I would wonder what came first, the atmosphere, or the oceans? Seeing that this process is what it seems is required for an atmosphere to be created, thereby requireing an ocean. Or am I wrong on gases in the earths asthenospheric mantle. Also, if this is the process that is required for gases to be an origination from volcano's, the genesis of the earth itself in the Solar system's evolution may be flawed. That is, the theory that the Earth was once a molten mass. If the earth ever was a liquid molten mass, gasses would easilly escape out of the earth, viscosity being of a much higher magnitude. Anyways, this is just a thought.


John Paul:
Ahh shoot! I remembered to put in in the 'quote' box but I forgot to cite it. Thanks True Creation and my apologies to the board. I took that out of Icons of Evolution pages 19-20 and it was NOT of my origin.

But anyway- volcanic outgassing is a very popular model for the Earth's primative atmosphere. That is in the Nebula hypothesis model of Earth's origins.

Do I agree with it- outgassing forming our alleged primative atmosphere or the nebula hypothesis- No.

You do bring up a valid point. Hopefully it will be discussed.

Again my apologies for not citing the quote.

------------------
John Paul


This message is a reply to:
 Message 4 by TrueCreation, posted 02-27-2002 6:30 PM TrueCreation has responded

Replies to this message:
 Message 11 by TrueCreation, posted 02-27-2002 9:28 PM John Paul has not yet responded

  
mark24
Member (Idle past 1691 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 6 of 85 (5736)
02-27-2002 7:41 PM
Reply to: Message 3 by John Paul
02-27-2002 5:25 PM


quote:
Originally posted by John Paul:

Life isn't just about chemical reactions. How long is it going to take before you realize that?

Can you show it's anything more than that? It'll probably take as long as it takes you to show it, JP, before I "realise" it.

Also, no one's saying DNA was the original self replicating molecule.

Mark

------------------
Occam's razor is not for shaving with.


This message is a reply to:
 Message 3 by John Paul, posted 02-27-2002 5:25 PM John Paul has responded

Replies to this message:
 Message 7 by John Paul, posted 02-27-2002 8:07 PM mark24 has responded

    
John Paul
Inactive Member


Message 7 of 85 (5738)
02-27-2002 8:07 PM
Reply to: Message 6 by mark24
02-27-2002 7:41 PM


quote:
Originally posted by mark24:

Can you show it's anything more than that? It'll probably take as long as it takes you to show it, JP, before I "realise" it.

Also, no one's saying DNA was the original self replicating molecule.

Mark


John Paul:
Life begets life. That is all but proven. The more we look at life the more we realize how IC it is. The black box has been opened, no longer can we ignore the contents or what they tell us.

Also it is obvious that DNA wasn't the first self-replicating molecule. It is also obvious it wasn't RNA. So what do you suggest?

------------------
John Paul


This message is a reply to:
 Message 6 by mark24, posted 02-27-2002 7:41 PM mark24 has responded

Replies to this message:
 Message 8 by Mister Pamboli, posted 02-27-2002 8:26 PM John Paul has not yet responded
 Message 9 by mark24, posted 02-27-2002 8:35 PM John Paul has not yet responded
 Message 10 by joz, posted 02-27-2002 9:02 PM John Paul has not yet responded

  
Mister Pamboli
Member (Idle past 4073 days)
Posts: 634
From: Washington, USA
Joined: 12-10-2001


Message 8 of 85 (5739)
02-27-2002 8:26 PM
Reply to: Message 7 by John Paul
02-27-2002 8:07 PM


[QUOTE][b]Life begets life. That is all but proven.[/QUOTE]

[/b]
That rules out God, then, doesn't it?
[QUOTE][b]The black box has been opened, no longer can we ignore the contents or what they tell us.[/QUOTE]

[/b]Enough with the Black Box already! You sound like the Bellman - "I have said it thrice: What I tell you three times is true."
Behe cites the 40 years of research which opened the black box of the cell. No one has ever ignored its implications - I cannot think of any subject in science which currently attracts more research dollars like mutant fruit flies to jam. And you know what, JP - the people who did the research were overwhelmingly evolutionists, the people who do the research are overwhelmingly evolutionists, and before after and during their research they remain, overwhelmingly, evolutionists.
Some change their mind, sure enough, but the majority find no challenge to the principle of evolution in their work.
Darwin's Black Box? More like the last squeak of creationism, struggling in its own mousetrap.

[This message has been edited by Mister Pamboli, 02-27-2002]


This message is a reply to:
 Message 7 by John Paul, posted 02-27-2002 8:07 PM John Paul has not yet responded

  
mark24
Member (Idle past 1691 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 9 of 85 (5740)
02-27-2002 8:35 PM
Reply to: Message 7 by John Paul
02-27-2002 8:07 PM


Peptide Nucleic Acid? (PNA)

------------------
Occam's razor is not for shaving with.


This message is a reply to:
 Message 7 by John Paul, posted 02-27-2002 8:07 PM John Paul has not yet responded

    
joz
Inactive Member


Message 10 of 85 (5742)
02-27-2002 9:02 PM
Reply to: Message 7 by John Paul
02-27-2002 8:07 PM


quote:
Originally posted by John Paul:
Also it is obvious that DNA wasn't the first self-replicating molecule. It is also obvious it wasn't RNA. So what do you suggest?

An autocatalytic cycle......


This message is a reply to:
 Message 7 by John Paul, posted 02-27-2002 8:07 PM John Paul has not yet responded

Replies to this message:
 Message 12 by TrueCreation, posted 02-27-2002 9:33 PM joz has responded

  
TrueCreation
Inactive Member


Message 11 of 85 (5745)
02-27-2002 9:28 PM
Reply to: Message 5 by John Paul
02-27-2002 7:02 PM


Hey no problem, but in all truth, I guess I was refering to your quote along with Quetzal's entire article, its very extensive for a single post I would think so my suspition was arroused. I think I bring up a valid point for discussion, though who am I to know as if it is entirely valid myself, being the producer of its question. Its just one of those many many questions I think of when I read textbooks on the subject that seem to have niches in them along the way with theoretical implications of a various explination in terms of the old earth. Also in the same order, it is analogous to say that when reading something in that nature I find that new information entirely supportive of the YEC view.

------------------


This message is a reply to:
 Message 5 by John Paul, posted 02-27-2002 7:02 PM John Paul has not yet responded

Replies to this message:
 Message 29 by Quetzal, posted 03-01-2002 4:11 AM TrueCreation has not yet responded

  
TrueCreation
Inactive Member


Message 12 of 85 (5746)
02-27-2002 9:33 PM
Reply to: Message 10 by joz
02-27-2002 9:02 PM


"An autocatalytic cycle......"
--Well ofcourse it had to have been an autocatalytic reactive. Meiosis and mitosis are simply chemical reactions replicating the cell, though with a pre-designed direct influence. Its quite easy to say the basic mechenism, its another thing to explain how this mechenism contributes to a probable event. Abiogenesis isn't as simple as photosynthesis for instance being a cyclic continuum (even though photosynthesis is in still vastly complex).

------------------

[This message has been edited by TrueCreation, 02-27-2002]


This message is a reply to:
 Message 10 by joz, posted 02-27-2002 9:02 PM joz has responded

Replies to this message:
 Message 13 by joz, posted 02-27-2002 9:45 PM TrueCreation has responded

  
joz
Inactive Member


Message 13 of 85 (5748)
02-27-2002 9:45 PM
Reply to: Message 12 by TrueCreation
02-27-2002 9:33 PM


Try this in 1861 Butlerov described the formose reaction in which a solution of sugars and formaldehyde formed more sugars....

Given that one of the problems with the primordial soup theory is the low ammounts of ribose sugar formed in the Urey-Miller experiments and given that formaldehyde was produced in large quantities in those experiments this would allow an autocatalytic cycle that would bring the concentration up to the required levels.....


This message is a reply to:
 Message 12 by TrueCreation, posted 02-27-2002 9:33 PM TrueCreation has responded

Replies to this message:
 Message 14 by TrueCreation, posted 02-27-2002 10:17 PM joz has responded

  
TrueCreation
Inactive Member


Message 14 of 85 (5750)
02-27-2002 10:17 PM
Reply to: Message 13 by joz
02-27-2002 9:45 PM


"Try this in 1861 Butlerov described the formose reaction in which a solution of sugars and formaldehyde formed more sugars...."
--formaldehyde is the most primative aldehyde, also, I think that it takes a bit more than sugars to get life started off, you must end up with enough cyclic reations to take place in an alotted time before your moledules tend to dissipate. You must have a phase in which there is replication, thus an evolutionary process.

"Given that one of the problems with the primordial soup theory is the low ammounts of ribose sugar formed in the Urey-Miller experiments and given that formaldehyde was produced in large quantities in those experiments this would allow an autocatalytic cycle that would bring the concentration up to the required levels....."
--Required levels for what, whats the next reaction? Also we should take into account the defectives in Millers experiment.

------------------


This message is a reply to:
 Message 13 by joz, posted 02-27-2002 9:45 PM joz has responded

Replies to this message:
 Message 15 by LudvanB, posted 02-27-2002 10:24 PM TrueCreation has responded
 Message 19 by joz, posted 02-28-2002 12:02 AM TrueCreation has not yet responded

  
LudvanB
Inactive Member


Message 15 of 85 (5751)
02-27-2002 10:24 PM
Reply to: Message 14 by TrueCreation
02-27-2002 10:17 PM


quote:
Originally posted by TrueCreation:
"Try this in 1861 Butlerov described the formose reaction in which a solution of sugars and formaldehyde formed more sugars...."
--formaldehyde is the most primative aldehyde, also, I think that it takes a bit more than sugars to get life started off, you must end up with enough cyclic reations to take place in an alotted time before your moledules tend to dissipate. You must have a phase in which there is replication, thus an evolutionary process.


LUD:Isen't it kinda like saying that a few cancer cells prove that people use to live 900 years and one lion eating vegetation means that the whole cat kind used to live on this diet? The formose reaction is an indication of the POSSIBILITY of Abiogenesis...Since when do you have a problem with POSSIBLE theories...or are they only good when they serve YOUR side of the equation?


This message is a reply to:
 Message 14 by TrueCreation, posted 02-27-2002 10:17 PM TrueCreation has responded

Replies to this message:
 Message 16 by TrueCreation, posted 02-27-2002 11:45 PM LudvanB has responded

  
1
23456Next
Newer Topic | Older Topic
Jump to:


Copyright 2001-2014 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2014