Origin of birds confirmed by exceptional new dinosaur fossils

_{Mario Lopez

September 26, 2009

Darwinism, Evolution, Science}

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Press release issued 25 September 2009

From the Society of Vertebrate Paleontologists annual meeting at the University of Bristol, UK

Chinese scientists today reveal the discovery of five remarkable new feathered dinosaur fossils which are significantly older than any previously reported. The new finds are indisputably older than Archaeopteryx, the oldest known bird, at last providing hard evidence that birds evolved from dinosaurs.

Comments

Surprise, surprise...an already answered assertion being regurgitated yet again by the usual suspects. So I'll just post it again:
The vagal nerve splits off early to provide some innervations to the larynx. This is called the superior laryngeal nerve (left and right). After looping around the aorta, the recurrent laryngeal nerve comes back up and also innervates the larynx. I thought that these were going to different areas, but there is much more too it. The superior and recurrent laryngeal nerves reconnect in what is called Galen’s anastomosis. This is odd in the sense that there are nerves that split off early and provide direct innervations while there are others that are taking the circuitous route. Neuroanatomists describe the innervation of the larynx as “complicated” and they are still trying to work out exactly what the specific targets are of the nerves. Apparently there is also some overlap. I had strongly suspected that there were developmental reasons for the circuitous route. There still may be, except now I am suspicious that there are some potential benefits in an overlapping sensory and motor innervations with some of the nerves being slightly longer. I would even go out on a limb to predict that when we find out what is really going on with the laryngeal innervation, there will be a phenomenal necessity for the slightly longer route for the nerve. Here is something that is odd. With superior laryngeal nerve paralysis (this is the one that comes off and is not circuitous) people have difficulty increasing loudness and getting a high pitch. They also have vocal fatigue and an inability to sing. The vocal folds lack their normal tone and will not lengthen sufficiently. In contrast, paralysis of the recurrent nerve results in a weak voice that can sound like Mickey Mouse.
and
The answer relates to its developmental history. Check a human embryology text book for a detailed answer. It’s been argued that the looping spermatic chord (ductus deferens) is overly long as well, although descent from its point of origin in the abdomen appears to be the reason. Likewise, the recurrent nerve, part of the vagus bundle looping under the posterior sides of the aorta may have a similar cause, since the heart descends during late embrogenesis, bringing the nerve bundle with it. But there may be other reasons for its placement, i.e. auxiliary functions: (from Gray’s Anatomy, Henry Gray and Henry Carter:) “As the recurrent nerve hooks around the subclavian artery or aorta, it gives off several cardiac filaments to the deep part of the cardiac plexus. As it ascends in the neck it gives off branches, more numerous on the left than on the right side, to the mucous membrane and muscular coat of the esophagus; branches to the mucous membrane and muscular fibers of the trachea; and some pharyngeal filaments to the Constrictor pharyngis inferior.” So according Henry Gray’s description, nerve filaments emanate along its length from the cardiac plexus to the esophagus, which if accurate might well dictate its positioning. Whether due to a requisite embryogenic sequence, for optimal nerve routing, or even an evolutionary carryover, it is a workable routing in all mammals, and therefore lacks substance as an argument against design.
My thoughts on the topic. Albeit from a non-expert, and before I was aware that its gives off filaments to the heart, to the mucous membranes and to the muscles of the trachea. It provides multiple functions, not just one.
The new school has the front loading being the genetic algorithm embedded in/ on the DNA and other cellular components.
That’s why there’s all this talk of “active information” and “intelligent evolution”. Then there’s fractals and the fractogene concept. But personally I would think that a limited set of components would need to be explicitly predefined. Otherwise I would presume you’d run into the same problems of gradually traversing indirect pathways. Also, even if we presume that evolution via algorithms is not true we at least know that in modern creatures that complex morphological features are constructed algorithmically. Like plants and the repeating pattern of the leaves (the name for that escapes me at the moment). I’ve read that nerve and blood vessel growth in limbs is supposedly derived algorithmically. Darwinists will also cite the anterior and recurrent laryngeal nerves of the giraffe as an example of “poor design” since it loops ~15 feet around the neck and back from the brain to the larynx, presumably resulting in ~13 feet of “waste” (although I should note that there’s potentially other functional reasons for this design I’m not aware of). Well, sure, that does not seem to make sense if it’s body plan was statically defined like blueprints for a house. But it makes perfect sense if it’s partially defined algorithmically in order to compensate for variations in body shape [or size].
Patrick_{October 1, 2009
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PhilipW, Thanks. On the other hand, it is interesting to see that evolutionists have a tendency to claim that a designer would create living beings solely for the purpose of survival, and when extra features are found then they are claimed to be evidence for incompetent design at best. Actually, it is quite the opposite. Evolution is supposed to have that single objective, extra features are problems for them, and not for design theorists. This is obvious with the peacocks tail. If all single detail is taken into account, then the peacock is a wonderful piece of engineering. Now its tail does not seem to aid survival per se (yet the animal lives quite happily), but it is not an argument for non-design. Human designers do stuff just because it looks beautiful, don't they? Or what about "the kids love it" as a design objective? The purpose for the design of the peacock's tail could be any of these. However, ID is about detecting patterns that are typical of intelligence and atypical of unguided natural processes and not necessarily about all the reasons behind a design. In case of the peacock's tail everything, for me especially the nano-scale structure that results in diffraction patterns for the fantastic colours, are as far as possible from what random mutations and natural selection can do. As the article quoted by Adel DiBagno is a good example of this strawman argument while covering the real issues about how could evolution produce anything like this.Alex73_{September 30, 2009
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re: #26 Alex73 You are entirely correct about the manufacturing process. In addition, to expand just a bit, one should never confuse efficiency with effectiveness. It might be efficient to advertise by printing up a whole stack of fliers and leaving them on a busy street corner; but would it be effective? With a bit of thought it is not difficult to come up with innumerable examples of things, both in nature and in human activity, which are not particularly efficient but which are very effective! It's what you said... obvious to one skilled in the art.PhilipW_{September 30, 2009
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I like the idea of a flying dinosaur but did it? Too bad the poor fellow is gone because I would love to interview him to find out when he first decided it would be fun to fly. Perhaps he saw another do it and was just being a copy cat. There is nothing convincing in this fossil or in the conclusions reached by the reporter in writing of it. The general subject of flight is most interesting only if one goes back far enough, to the very first creature which flew. At that point there are very serious questions to ask. Flight is a complicated activity and it is reasonable to assume that there must have been a pressing need for it to have been developed. Our dinosaur friend may have wanted to eat flying insects but what did the insect (or whatever first flew) want to eat before there was any food flying around?PhilipW_{September 30, 2009
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I just bought a memory card, and it came in that impossible-to-open clamshell packaging. At first I thought the manufacturers were idiots. Don't they realize that whoever bought the thing probably intends to use it? But now I understand that something so poorly designed couldn't have been designed. It started off with a different purpose (a defense mechanism?) and when it evolved it retained certain properties that make for inefficient packaging. Only the weak-minded are fooled by any of the other signs of apparent design. With a little imagination we can find a more sciencey explanation.ScottAndrews_{September 29, 2009
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Where did this idea of Intelligent Design = Perfect Design come from?suckerspawn_{September 29, 2009
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On the recurrent laryngeal nerve, By JIM HOLT Published: February 20, 2005 http://www.nytimes.com/2005/02/20/magazine/20WWLN.html
What can we tell about the designer from the design? While there is much that is marvelous in nature, there is also much that is flawed, sloppy and downright bizarre. Some nonfunctional oddities, like the peacock's tail or the human male's nipples, might be attributed to a sense of whimsy on the part of the designer. Others just seem grossly inefficient. In mammals, for instance, the recurrent laryngeal nerve does not go directly from the cranium to the larynx, the way any competent engineer would have arranged it. Instead, it extends down the neck to the chest, loops around a lung ligament and then runs back up the neck to the larynx. In a giraffe, that means a 20-foot length of nerve where 1 foot would have done. If this is evidence of design, it would seem to be of the unintelligent variety.
Adel DiBagno_{September 29, 2009
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Mark Frank, Nerve impulses depend on timing. If the impulse gets to its destination too soon or too late then the organism will not have the maiximum chance to survive and reproduce. Also nerves connect, not just to one point- one destination- but to a variety of locations along its route.Joseph_{September 29, 2009
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Ho Hum, another feathered dinosaur- It appears the specimen was presented by a farmer and that people get money for bringing in this kind of stuff.Joseph_{September 29, 2009
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Mark, In think I agree with your last post. The real issue for me is the confident statement that the nerve is of poor design by people (RD et al) who otherwise claim that scientific evidence is the only thing that matters for them. It is a conjecture supported with only superficial observations, like those you mentioned, while they ignore two important things: 1. The immense complications with the construction of a giraffe 2. The animals live quite happily with this nerve. So this is just propaganda and very bad science. Just see how it stops people asking questions about possible functions etc. Your last paragraph brings up an interesting issue about how the optimal design of the flagellum affects the fitness of the E. Coli. Although it is the opposite of the giraffe issue (i.e. trying to degrade something obviously very good instead of fixing it) but could indeed expand our knowledge about the flagellum and the nano-engineering behind it. The point is that you are now asking questions which is just the thing we need.Alex73_{September 29, 2009
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#33 Could you, please, once again, provide evidence that the giraffes do not reproduce as much as they could because of the laryngeal nerve? I have written above that the only way to be certain would be to construct a population of giraffes with a shorter nerves. This is only a conjecture based on the fact there is no benefit that anyone has identified to having such a long nerve and there are some rather obvious (if small) advantages to the survival chances of the giraffe in having a shorter one. But I already wrote this - so I am not sure why you want me to write it again. Have you any hard facts that show that bacteria survive better because the proton motive force engine of the flagellum works at near 100% efficiency? Did you try constructing a bacterium with a less efficient flagellum and see if it did better or worse?Mark Frank_{September 28, 2009
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Mark, The objective is for the animal to have the maximum chance of surviving to reproduce. Could you, please, once again, provide evidence that the giraffes do not reproduce as much as they could because of the laryngeal nerve? I think they jolly well survive, and have gazillions of baby giraffes if their habitat is not exploited by humans or they are not hunted down by poachers. How many giraffes die each year because of nothing else, but damage to this nerve? Do you have the hard facts? But you have to wonder what on earth the benefit could be – especially as other animals manage perfectly well with a much shorter nerve. Exactly. I fully agree. I hope someone will research this issue. Or are you making the religious assumption that is must be optimal? Actually, I did not make this assumption, but I do expect a reason behind it. Too many things in a giraffe make me gasp if I think about them, so it is a logical extrapolation for me to expect that once we understand the whys behind the laryngeal nerve it will be just like almost anything else in this animal. BTW, you have previously concluded that there is no reason for the nerve length. Expecting a reason for an unexpected find in nature has always been a driving force of science, so I am glad to see that you see a chance for a function here. Cheers, AlexAlex73_{September 28, 2009
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Re #31 Well first, two assumptions: 1) The objective is for the animal to have the maximum chance of surviving to reproduce. 2) The way that nerves that connect the body with the brain help animals survive is by passing messages between body and brain. The first is just defining what we mean by optimal. The second is true as far as we know (unless you know something different?). Given these assumptions the shorter the nerve the better. The message gets passed more quickly, the chances of signal loss and damage are reduced. I admit there maybe unknown benefits to the giraffe of having a nerve that takes a fifteen foot detour to reach a destination a few inches away. I am not talking certainty here. But you have to wonder what on earth the benefit could be - especially as other animals manage perfectly well with a much shorter nerve. Or are you making the religious assumption that is must be optimal?Mark Frank_{September 28, 2009
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Mark Frank- How do you know how long any nerve has to be?Joseph_{September 28, 2009
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How many more times must we be tormented with the Darwinian “finality” claim of the absolute and undeniable truth of the creative power of Darwinian incrementalism? Darwin Theory Is Proved True, New York Times.tribune7_{September 28, 2009
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Lecomte du Nouy, a French evolutionist, stated that birds have "all the unsatisfactory characteristics of absolute creation" (Human Destiny, 1947, p. 72)--unsatisfactory, maybe, to the theory of evolution.Barb_{September 28, 2009
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Mark, What you write amounts to saying that we can never know if a particular aspect of a living thing is optimally designed or not. No it isn't. The decision can be made, just requires copious amount of research and asking questions of "why?" or even "can it be done any other way?" instead of jumping to conclusions. For example, some enzimes have already been proven to be optimal, because they catalize a particular reaction just at the speed diffusion can deliver the next molecule to their vicinity. Or the proton motive force engine of the flagellum that works at near 100% efficiency. The difference between these examples and the giraffe is that the set of variables defining what is optimal is small enough for us to manage them. The giraffe is stuffed with brilliant engineering, just to mention the ATP synthetise, or the ribosome. Actually, trillions of them. We now can appreciate these because of research done in the past. The same thing about the single laryngeal nerve is in the future, I think. To round it off, just one final remark: The unusual length of the laryngeal nerve is used as evidence for evolution claiming that it was poorly designed. However, RD and his pals cannot even properly demonstrate that is indeed a poor design. So this claim is just a bluff, because it is not susbtantiated with the necessary analysis and expertise in the field. Cheers, Alex PS: being optimal is not required for anything to be designed.Alex73_{September 28, 2009
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Alex73 #26 What you write amounts to saying that we can never know if a particular aspect of a living thing is optimally designed or not. Now vjtorley wrote in #15 above: The default design hypothesis would be that feathers were designed because they were an optimal solution to the problem of generating a warm-blooded creature that could fly It looks like you are saying that this is actually an untestable hypothesis.Mark Frank_{September 28, 2009
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Mark, I agree with you about reconstructing a giraffe, but reconstruction has to be done at the genetic level and see it work through the entire development of the creature. A prostetic retro-fitted short nerve would not do. Let me explain why. The manufacturing of an animal is an extremely complicated process which is very poorly understood in spite of our growing knowledge abour embryology. Any manufacturing process has trade-offs for optimality and viability of the entire product. Even in case of the simplest components, like a cast iron mounting, extra material is used because it makes it easier to produce the pattern if it has roundings. Or software engineers use memory and processor hungry high level languages instead of the optimal assembly code because it is faster to create the program that way. A longer code is more vulnerable, isn't it? (BTW: Any animal is vulnerable...) Anybody criticising these practices would be laughed off by those doing the actual stuff: they would speak of ignorance. Now a giraffe is extremely complicated and we know almost nothing about how to make one. As there could be hundred plus reasons why that nerve has to grow that way, for example, because the nerves have to be in place very early in the embryo in a particular configuration to enable the actual body plan to develop. So it is actually perfectly all right to ask more evidence for yor claims, especially you haven't ever made one giraffe from scratch. Try it! See it for yourself! Now that would be proper science. Until your first prototype it is best to remain a little bit slow to jump to conclusions. Cheers, AlexAlex73_{September 28, 2009
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On the viability of a giraffe with a shorter laryngeal nerve (vjtorley 23, alex73 22). The only way to prove beyond all doubt that a design was suboptimal would be to take the animal apart and reconstruct it with the new design. But the laryngeal nerve comes pretty close to being conclusive. It is some 15 feet longer than it needs to be. As well being a waste of resources this makes it prone to injury. Other animals work perfectly well with much shorter laryngeal nerves. What more proof could you ask for?Mark Frank_{September 27, 2009
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Khan (#17) Thank you very much for the link you provided on the molecular evolution of feathers. I've had a look at it, and it appears to be both mathematically rigorous and experimentally well-tested. I would strongly recommend that interested readers have a good look at Khan's link: http://www.pnas.org/content/102/33/11734.full What the above article demonstrates is that the changes in embryonic development required to transform an ancestral featherless theropod dinosaur into a creature with pennaceous feathers required no sudden leaps; a series of incremental changes would have sufficed to effect the change. OK. How does that affect the case for ID? Personally, the news that feathers probably evolved through an undirected process doesn't faze me. As UD readers are well aware, there are much better examples of design in nature than feathers. What the article cited by Khan ultimately shows is that the complexity of a biological structure, by itself, cannot tell us whether it was designed. What we need to look at are the instructions for making the structure. Then we need to establish that these instructions could not have originated in an incremental fashion, as a result of a blind winnowing process, before ascribing the instructions to an intelligent Designer. Feathers look wondrously complex; but the article cited by Khan (#17) makes a very good mathematical and empirical case that the molecular instructions for making feathers are simply the culmination of a series of stepwise refinements that required no intelligent oversight. In other words, feathers are not irreducibly complex. In the nineteenth century, they would have constituted a powerful prima facie example of a designed structure; now we know better. We also have much better examples of structures requiring intelligent design - such as the ribosome - that our nineteenth century forebears never dreamed of. This suffices to refute any atheistic argument that the case for design in nature relies on "God of the gaps" reasoning. As our knowledge of the cell increases, we find that the gaps are more numerous than ever before. In the meantime, thanks to the work of Dembski, Behe, Meyer and many other thinkers, the criteria for design have been sharpened and clarified. The machine metaphor has yielded powerful insights for understanding the workings of the cell at the nano scale. It has also uncovered numerous irreducibly complex structures within the cell. That's where we need to look. Forget about eyes and feathers. Computer science can also shed new light on the cell, thereby strengthening the case for design, as this new post by niwrad persuasively argues. The cell can be viewed as a Turing machine. Turing machines require intelligent design. More and more, cells are starting to look like units that required a lot of intelligent planning to create in the first place, and the complexity of eukaryotic cells only serves to compound the difficulty facing proponents of the hypothesis that blind processes can account for the origin of cells. Stephen Meyer's Signature in the Cell has ripped the standard textbook accounts of the origin of life to shreds. The irony is that Meyer's argument for intelligent design from DNA is based on the very same method of scientific reasoning that Darwin himself used. I hope that what I have written provides at least a partial answer to Mark Frank's request (#21) for "an explanation of why some things are designed and some are not." Alex73: Thanks for your entertaining story about the computer cable. You make a good point: the viability of a giraffe with a shorter laryngeal nerve has yet to be established.vjtorley_{September 27, 2009
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Mark, You write: ...you must accept the many instances of poor design in nature as evidence against design e.g the famous laryngeal nerve of the giraffe with its extraordinary trip from the brain down the neck round the aorta and back to the throat. Could you, please, substantiate your claim that the layngeal nerve of the giraffe is poor design? I needed something more than "it is apparently much longer than the shortest one possible". I have heared this argument countless times, never supported with any analysis at all. Let me give you an example that you may appreciate. We had two PCs on top of each other that had to communicate through Ethernet. So they were connected using a 10cm long Ethernet cable. Unfortunately, although the cable was perfect, they just could not talk to each other, beacause the transfer of high frequency signals required a minimum cable length (see the Ethernet specs). The solution was simply to take a 1.5m cable, coil it up and plug it in. Voila, the cards were working. The uninitiated could easily ridicule this long cable, however, that criticism comes from ignorance. Now according to your definition this solution is poor design. Well it isnt. It was optimal in terms of cost and manufacturing. The giraffe is a perfectly functional construction with plenty of marvellous technical solutions. One unusual, but functional bit does not even make it poorly designed. Also, obviously poor design in case of e.g. dodgy cars that often break down is not evidence for non-design. Anyway, when Richard Dawkins and his pals construct a giraffe breed with a short laryngeal that can survive in the wild at least as well as the present one, then they might have a case. For evolution? Nope. Poor design? Not even that. Only for showing that an alternative solution is also functional. So this giraffe argument does not take us anywhere. However, the scientific progress so far was a continuous flow of surpizes, wows and "Hey, look at that!"-s. I bet that there will be a reason for this unusual nerve. Now if you believe that it is just a mistake and there in reason to look for a purpose behind it, serves you right. Cheers, AlexAlex73_{September 27, 2009
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Re #18 I still don't see the value of your sequence of conditional probabilities. Each of them is subject to the same concern - probability of what? I’m assuming that the Designer is interested in doing a good job, that’s all. It’s always possible to suppose that the Designer is lazy or inept, of course, but that’s an ad hoc assumption. Good for what? The man who designs cars that rust and become obsolete is doing an excellent job for his organisation in increasing sales. Even if you assume some overall objective for the designer, surely it is just as much an ad hoc assumption that the designer is highly competent and efficient as that it is lazy or inept. What this strongly suggests is that some structures found in living creatures were not designed. I have no problem with that. So every time you come across something that might count as evidence against design you can side-step it by saying - ah well that wasn't designed. That's why you need some independent evidence of design over and above complex structures that serve the organism well. Ideally an account of how design works so you can offer an explanation of why some things are designed and some are not.Mark Frank_{September 27, 2009
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Andrew, that paper has numerous problems with it, including their ignorance of the fact that flightless birds like kiwis have very similar air sac structures to theropods. for a more recent, and better, article on the evolution of avian air-sacs, see here: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0003303Khan_{September 27, 2009
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Andrew Sibley writes:
vjtorley – the problem for theropod to bird evolution is much more complex than feathers – if feathers aren’t complex enough – it is worth reading this paper. John A. Ruben, Terry D. Jones,* Nicholas R. Geist, W. Jaap Hillenius Lung Structure and Ventilation in Theropod Dinosaurs and Early Birds http://www.sciencemag.org z SCIENCE z VOL. 278 z 14 NOVEMBER 1997 Lung Structure and Ventilation in Theropod Dinosaurs and Early Birds
This more recent paper might be more enlightening: O’Connor PM & LPAM Claessens (2005). Basic avian pulmonary design and flow-through ventilation in non-avian theropod dinosaurs. Nature 436: 253-256. Abstract (my emphasis):
Birds are unique among living vertebrates in possessing pneumaticity of the postcranial skeleton, with invasion of bone by the pulmonary air-sac system1–4. The avian respiratory system includes high-compliance air sacs that ventilate a dorsally fixed, non-expanding parabronchial lung2,3,5,6. Caudally positioned abdominal and thoracic air sacs are critical components of the avian aspiration pump, facilitating flow-through ventilation of the lung and near-constant airflow during both inspiration and expiration, highlighting a design optimized for efficient gas exchange2,5–8. Postcranial skeletal pneumaticity has also been reported in numerous extinct archosaurs including non-avian theropod dinosaurs and Archaeopteryx9–12. However, the relationship between osseous pneumaticity and the evolution of the avian respiratory apparatus has long remained ambiguous. Here we report, on the basis of a comparative analysis of region-specific pneumaticity with extant birds, evidence for cervical and abdominal air-sac systems in non-avian theropods, along with thoracic skeletal prerequisites of an avian-style aspiration pump. The early acquisition of this system among theropods is demonstrated by examination of an exceptional new specimen of Majungatholus atopus, documenting these features in a taxon only distantly related to birds. Taken together, these specializations imply the existence of the basic avian pulmonary Bauplan in basal neotheropods, indicating that flow-through ventilation of the lung is not restricted to birds but is probably a general theropod characteristic.
Dave Wisker_{September 27, 2009
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vjtorley - the problem for theropod to bird evolution is much more complex than feathers - if feathers aren't complex enough - it is worth reading this paper. John A. Ruben, Terry D. Jones,* Nicholas R. Geist, W. Jaap Hillenius Lung Structure and Ventilation in Theropod Dinosaurs and Early Birds www.sciencemag.org z SCIENCE z VOL. 278 z 14 NOVEMBER 1997 Lung Structure and Ventilation in Theropod Dinosaurs and Early BirdsAndrew Sibley_{September 27, 2009
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Mark Frank Thank you for your post. You write:
For any feature of living things you can define it in sufficient detail so the probability of developing that feature is arbitrarily low.
I'd like to clarify what I'm talking about here. Suppose that geneticists, after a careful examination of reptile and bird embryos, as well as feathers in living and extinct birds, propose a 100-step genetic sequence of changes that would have been required to get from reptilian scales to the feathers found in Archaeopteryx. Let's call the steps A1 to A100. I'm not asking for the probability of A100, given A1. That would be very low, and as you rightly point out, the more specific the description of the feathers in question, the lower the probability will be. What I want to know are the conditional probabilities P(A2/A1), P(A3/A2), ..... P(A100/A99). So long as it could be shown that none of these incremental steps is astronomically improbable, I'd be happy with a gradualistic explanation of the origin of feathers.
Are you assuming that the designer wants creatures that have feathers to be well insulated and fly well (of course, this makes life harder for the creatures that feed on them).
I'm assuming that the Designer is interested in doing a good job, that's all. It's always possible to suppose that the Designer is lazy or inept, of course, but that's an ad hoc assumption. Feathers are macroscopic structures that strike many laypeople as too improbable to have arisen by chance. That intuition may or may not be correct. However, if it is indeed true that feathers were designed, then one has to ask: what for? Insulation and flight are the two most obvious objectives. It is irrelevant at this point to ask how this will impact other creatures, unless there is evidence that they also possess structures that were designed.
If you are accepting "optimal design for the purpose of the helping the organism reproduce/live longer" as evidence for design then presumably you must accept the many instances of poor design in nature as evidence against design e.g the famous laryngeal nerve of the giraffe ...
Actually, I do. For all I know, the laryngeal nerve of the giraffe may have been designed, but it certainly does not look that way. What this strongly suggests is that some structures found in living creatures were not designed. I have no problem with that.vjtorley_{September 27, 2009
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vjtorely, if you want to see some nice research on the molecular evolution of feathers, look here: http://www.pnas.org/content/102/33/11734 ps the hypothesis that feathers evolved from scales was discarded a long time ago.Khan_{September 27, 2009
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vjtorley (1) Personally, I see no reason why we shouldn’t calculate probabilities for all of the above, but the most important thing is for scientists to identify a “most likely genetic pathway” from an ancestor with scales to a descendant with feathers, and to calculate probabilities for each step along the path. I don't see the point of this calculation. To see why - suppose that we get more specific information about the early feathers - perhaps the number of spines - will you now ask scientists to assess "the most likely genetic pathway" to feathers with these specific characteristics? For any feature of living things you can define it in sufficient detail so the probability of developing that feature is arbitrarily low. More generally - there is no such thing as "the" probability of an event. You have to give it a description/specification as a class of events. Even throwing a six is a class of events - there are many different ways of throwing a six. Any event can be described in a way that makes it as probable or improbable as you wish. You have to justify why you are calculating the probability of that particular specification rather than another. (2) What you are essentially suggesting here is that evolution might still be true even if the underlying mechanism driving it (”RM+NS”) is completely different from what we currently suppose it to be. If this is so, then calculating the probability of feathers arising through evolutionary processes would indeed be a waste of time – but only because the evolutionary hypothesis was unfalsifiable (and hence scientifically useless). Putting it another way: are there any assumptions about RM+NS that you would not be prepared to jettison under any circumstances? If feathers were impossible under the assumptions of RM+NS then I would reject RM+NS as an explanation of feathers. It would be not only falsifiable but falsified. It would be necessary to find an alternative explanation.One alternative might be some kind of designer but I see no reason why that alternative should not be subject to the same criteria. How probable are feathers given a designer? To make the calculation we need to know something about the designer. You feel that it would be evidence for a designer if the design were optimal. Optimal for what? Are you assuming that the designer wants creatures that have feathers to be well insulated and fly well (of course, this makes life harder for the creatures that feed on them). If you are accepting "optimal design for the purpose of the helping the organism reproduce/live longer" as evidence for design then presumably you must accept the many instances of poor design in nature as evidence against design e.g the famous laryngeal nerve of the giraffe with its extraordinary trip from the brain down the neck round the aorta and back to the throat. Usually when this or any other instance of poor design for the organism is raised the ID response is that we don't know what the designer is trying to achieve or the full context of how it is trying to achieve it. So it proves remarkably difficult to establish what counts as optimal.Mark Frank_{September 27, 2009
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Mark Frank Thank you for your post, and for the questions you raised. You ask:
In ID speak – what is the specification: feathers, flight enabling modification of some kind, any kind of fitness advantage?
That's a good question. Personally, I see no reason why we shouldn't calculate probabilities for all of the above, but the most important thing is for scientists to identify a "most likely genetic pathway" from an ancestor with scales to a descendant with feathers, and to calculate probabilities for each step along the path. You also write:
Even if you somehow decide on a specification and magically conjure up a calculation – then what? All you have achieved is to show that some of the assumptions about RM+NS are wrong. It is important but it says nothing about design.
What you are essentially suggesting here is that evolution might still be true even if the underlying mechanism driving it ("RM+NS") is completely different from what we currently suppose it to be. If this is so, then calculating the probability of feathers arising through evolutionary processes would indeed be a waste of time - but only because the evolutionary hypothesis was unfalsifiable (and hence scientifically useless). Putting it another way: are there any assumptions about RM+NS that you would not be prepared to jettison under any circumstances? I would maintain that if, based on our current knowledge of how genetic change occurs, a natural pathway from scales to feathers appears astronomically improbable, then it is reasonable to entertain the working hypothesis that feathers were designed - even if we know nothing about the identity of the Designer. Science proceeds by testing hypotheses. The default design hypothesis would be that feathers were designed because they were an optimal solution to the problem of generating a warm-blooded creature that could fly - a problem requiring considerable foresight on the Designer's part, as the evolution of birds took tens of millions of years. Evidence that feathers are in fact a suboptimal solution to the twin engineering objectives of flight and insulation (after taking into account the relevant anatomical limitations of the creatures for whom they were supposedly designed) would of course discredit this working hypothesis, but that would not establish the truth of evolution. It would simply mean that both ID proponents and evolutionists needed to do some more research. So there we have it. The fact that birds are descended from dinosaurs is now reasonably well-established; what scientists now need to investigate is how they did so.vjtorley_{September 27, 2009
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