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Author | Topic: Evolution vs. Thermodynamics | |||||||||||||||||||
Randy Member (Idle past 6275 days) Posts: 420 From: Cincinnati OH USA Joined: |
quote: I don’t think your understanding is quite right. Examples such as shuffled cards or marbles getting mixed up are often used to illustrate entropy and the second law especially in popular writing. However, these analogies are only analogies and it is not correct to take them completely literally. Compare mixing marbles to mixing gases for example. If I have a partioned box with equal sized partitions and with one mole of ideal gas A on one side and and one mole of ideal gas B on the other at room temperature and remove the partition mixing will occur until after a long enough time there will be A and B equally distributed throughout the box and the entropy of mixing can be calculated(deltaSmix = 2Rln2 in this case). However, if I have a partioned box full of red marbles on the one side and blue on the other and remove the partition they will not mix. If leave the box undisturbed a million years there will still be red marbles on one side and blue on the other. A similar fact is true with cards. If you leave the cards alone and don’t put in energy by shuffling them they will never get disordered You can find discussion of why human concepts of order and disorder do not really relate to entropy and the second law by Frank L. Lambert : Shuffled Cards, Messy Desks, and Disorderly Dorm Rooms - Examples of Entropy Increase? Nonsense! Just a moment... and by creationist physicist Doug Craigen: Entropy, Disorder and Evolution: Entropy, Disorder and Evolution Randy
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Randy Member (Idle past 6275 days) Posts: 420 From: Cincinnati OH USA Joined: |
quote: Not quite. 1. Increasing entropy results in a reduction of the energy available to do work. In classical thermodynamics it is the interal of dQ/T where T is temperature and Q is heat.2. Total entropy always increases in an isolated system. quote: I think the point is that no useable energy resides in the order of the cards. The order only means something because we assign meaning to particular suits and numbers that are painted on the cards. Cooling a deck of cards will lower its entropy and heating it will raise its entropy but neither will change its the card "order" and the energy released by burning a deck of cards will not depend on card order. As to shuffling cards leading to randomness I guess it depends on who shuffles them. I know a magician who can do several perfect shuffles in a row. IIRC there are even a few magicians who can do enough perfect shuffles to get the deck back in its original order. Randy
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Randy Member (Idle past 6275 days) Posts: 420 From: Cincinnati OH USA Joined: |
quote: Not exactly. It is why reactions that release sufficient heat can be spontaneous even though they may lead to products with lower entropy than the reactants. Delta H is negative when heat is released and long as delta H is greater than TdeltaS the reaction is spontaneous even if deltaS is also negative. The only "mechanism" you need is for the reaction to have negative free energy under the conditions where it occurs. I think we have been over this before in some detail.Randy
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Randy Member (Idle past 6275 days) Posts: 420 From: Cincinnati OH USA Joined: |
quote: All of this has been answered before by myself and others. I suggest you look back at post #66 by Percy or any of several I and others have made on this subject. You can question the plausibility of any of the several current scenarios put forth as possible paths to abiogenesis but to claim that you can show that abiogenesis must have violated the second law is simply wrong for reasons that have been explained several times to you now. You don't know what the required reactions may have been or what sequence they may have occurred in let alone the reaction conditions where they may have occurred. Without this knowledge you can't prove that abiogenesis violated the second law. If I were really going to explain abiogenesis I might need to come up something similar to the mechanisms you describe (though your wording is a little confusing) but they really do go beyond thermodynamics. I am not trying to prove that abiogenesis occurred or how it occurred. I am only saying that you can't prove that it didn't occur naturally by using the second law. If you want to discuss how abiogenesis might have occurred, this board has a separate forum on the origin of life.Randy
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Randy Member (Idle past 6275 days) Posts: 420 From: Cincinnati OH USA Joined: |
quote: This has all been discussed and answered at several places on this thread, including just above. Please read posts 50, 54, 66 and 91 of this thread for discussion of points 1 and 2, and of course "experimenter interference is needed since conditions present on the prebiotic earth are no longer present in nature. As to 3, "complex specified information" is not part of thermodyanmics. This has also been discussed on this thread. I don't expect it will ever be possible to prove exactly how life arose on earth or prove that it did have a natural origin. The best that will be done is to develop scenarios that are more and more plausible. However, to prove that the second law prevented life from arising naturally you must show exactly which reactions where absolutly necessary for abiogenesis and show that there were no possible conditions on the prebiotic earth where these reactions could have occured. You don't and can't know this information therefore you can't prove that the second law prevented abiogenesis. BTW your description of entropy and the reasons for chemical bond formation are not very precise. In statistical thermodynamics the entropy may be defined as Boltzmann's constant time the log of the number of quantum states of a system with equivalent energy but this relationship only holds under very specific conditions and I don't think that anyone has yet started with statistical mechanics and derived a general statement of the second law of thermodynamics that holds in all conditions. In classical thermodynamics, where the second law is defined (though not dervided mathematically), the entropy change in a process is the integral of the differential of the heat (reversible heat flow) divided by the absolute temperature when the process is carried out in a reversible fashion. It is the sum of the changes in this quantity in a system and its surroundings that can never decrease and that must increase for the universe as a whole (system + surroundings) in any irreversible (ie real) process. In equilibrium thermodynamics the direction of a reaction is determined by the free energy change which is influenced by reaction conditions. Chemical bonds form when the enthalpy of bond formation is negative (heat is released) and is greater than the product of the reduction in entropy times the absolute temperature under the conditions of the reaction. They are trying establish "minimal bond energy" whatever that means. Reactions that are not favorable can be driven if they are coupled to other reactions that are favorable. Randy
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Randy Member (Idle past 6275 days) Posts: 420 From: Cincinnati OH USA Joined: |
quote: But systems can get locked into non optimum metastable states for ever if the activation energy necessary to get back over the hump between the metastable and the equilibrium state is not supplied.
quote: Actually the broadest possible energy distribution may be a better way to state it.
quote: This is true for macroscopic systems but there are deviations in microscopic systems. We have discussed this a bit before. Here are the links that were brought up then. Page not found | American Institute of Physics
Abstract Link http://arxiv.org/ftp/cond-mat/papers/9901/9901258.pdf
quote: Energy must be supplied true. That’s why it is fortunate that we are not dealing with an isolated system.
quote: Because no one has done it to date you assume that no one will. This assumption has not been justified about other scientific studies in the past. Why are you so sure that it is now. How do you know that the conditions will be far more favorable when you don’t know what the conditions were? I do suppose that we must use more favorable conditions though since we probably don’t want to wait 100,000,000 years to see what happens.
quote: CSI? It is well known that conditions on the prebiotic earth would have been quite different. What is your point?
quote: Ah the old bogus post hoc calculation of probability. In my this really has little to do with the second law and has been answered many times before.
quote: Exactly my point.
quote: How do you know what I have to assume? What about the presence of temperature gradients? Macromolecules created at one temperature could diffuse to regions of lower temperature where they would be stable. What about catalysts and coupled reactions? There are far too many unknowns here to claim that you can show that the second law prevents abiogenesis. BTW since you are only talking about abiogenesis are you conceding that the second law does not prevent evolution. Randy
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Randy Member (Idle past 6275 days) Posts: 420 From: Cincinnati OH USA Joined: |
Richard wrote:
quote: Experimental Demonstration of Violations of the Second Law of Thermodynamics for Small Systems and Short Time ScalesG. M. Wang,1 E. M. Sevick,1 Emil Mittag,1 Debra J. Searles,2 and Denis J. Evans1 1Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia 2School of Science, Griffith University, Brisbane QLD 4111, Australia (Received 04 March 2002; published 15 July 2002) We experimentally demonstrate the fluctuation theorem, which predicts appreciable and measurable violations of the second law of thermodynamics for small systems over short time scales, by following the trajectory of a colloidal particle captured in an optical trap that is translated relative to surrounding water molecules. From each particle trajectory, we calculate the entropy production/consumption over the duration of the trajectory and determine the fraction of second law—defying trajectories. Our results show entropy consumption can occur over colloidal length and time scales. 2002 The American Physical Society In terms of statistical mechanics the second law represents a tendency. This tendency is overwhelming with large collections of particules over long time scale but significant fluctuations can occur in smaller systems at short time scales as this paper demonstrates.
quote: While the second law may hold in all macroscopic systems it is only in isolated systems that entropy must always increase as I think you know. It is also quite difficult to figure out exactly how to apply the second law in open systems that are not at least fairly close to equilibrium for the purpose of calculating entropy changes in processes. At least I think irreversible thermodynamics are a bit difficult especially at the statistical level. Maybe you don't but I do.
quote: Actually DNA and RNA are not made from amino acids at all. DNA codes for the production of amino acids through messenger RNA but DNA and RNA are of course made from nucleotides. Perhaps you should read a basic biochemistry text. I like Biochemistry by Chris Mathews and Ken van Holde but I am probably biased because I did a significant fraction of my Ph.D. research in Ken van Holde's lab many years ago.
quote: What the second law says is that transformations from one equilibrium state to another equilibrium state in thermodynamically isolated systems will lead to an entropy change that is greater than or equal to zero. There are many open systems far from equilibrium that spontaneously order. Examples are the Benard Instability in viscous solutions under temperature gradients and oscillating chemical reactions such as the Belousov-Zhabotinsky reaction.
quote: The common descent of all life on earth from previous ancestors going back to single celled organisms depends not one bit on how the first cells arose or appeared.
quote: As I said above DNA and RNA are not made from amino acids but that is beside the point. The formation of biopolymers involves chemical reactions. Chemical reactions will proceed if the free energy change is favorable. Unfavorable reactions can be driven if they are coupled to favorable ones. You don’t know what the reaction conditions were. You don’t know what sequence of reactions were absolutely required, how they may have been catalyzed or what reactions may have been coupled together. You don’t whether or not the currently proposed scenarios actually reflect what may have happened. Without this knowledge your arguments against abiogenesis do not and can not have the force of the second law of thermodynamics behind them. Many creationists, some of whom I expect know far more about thermodynamics than you do, understand that the second law does not prevent abiogenesis or evolution and I have given links to the web pages of a couple of them in previous posts but here they are again. http://members.aol.com/steamdoc/writings/thermo.html The page you were looking for doesn't exist (404) You are recycling arguments that have been discussed in detail in the posts that I asked you to read before. RandyPS I had a bit of difficulty sorting out your replies from my post. Please use some way to distinguish the two and the preview function to see if it worked in the future.
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Randy Member (Idle past 6275 days) Posts: 420 From: Cincinnati OH USA Joined: |
Richard,
You are still arguing from incredulity. Some of your arguments are worthy of discussion perhaps on the orgin of life forum. I suggest you might want to read some papers on abiogensis, perhaps in the journal Origin of Life and the Evolution of the Biosphere and maybe in some other journal. You can find them easily through medline searchs and a good college library should have them. You may find more research and hard thought in this area than you realized exists. But that is beside the point. Saying that we don't know if something happened, that we don't know how it happened if it did happen and that we may never figure out how it happened is not equivalent to saying that you can prove that it violated a fundamental law of nature if it did happen. What you have not done and cannot do is prove that evolution violates the second law of thermodynamics or prove that abiogenesis could not be a natural process because it must have violated that second law. Percy and I have both explained why you haven't done either can't hope to do either in some detail. Randy
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