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Author | Topic: Birds and Reptiles | |||||||||||||||||||||||||||
arachnophilia Member (Idle past 1370 days) Posts: 9069 From: god's waiting room Joined: |
faith24 writes: Birds cannot move their thigh bone so they must bend their knee while walking or running. Land creatures such as the theropods can move their thigh bone. Also birds required more oxygen than cold blooded animals and so to supply this need, birds have special lungs and supporting musculature. If birds have the same muscle structure as the dinosaurs and could move their thigh, their lungs would collapsed. what a load of sensationalist birds-came-first nonsense! allow me to break this down, point by point. while it might be true that femoral movement must be restricted (note: restricted, not prevented) in some flying birds to prevent collapse of the abdominal air sacs, this wold simply be a trade-off aimed at keeping flight muscles highly oxygenated. if there is really anything particularly to this idea at all, and i'm not convinced that there is. however, i know that when a bird relies more on use of its legs to survive, this condition is simply not found.
quote: rheas move their femora while running. this paper is a comparison between the gait and tracks of the modern rhea and theropod dinosaurs. it turns out that the ratite gait is very much like the dinosaurian one. further, here is a diagram of exactly how much an ostrich's femur rotates while running, from this article on ostrich locomotion. please note that i wrote "air sac" above, and not "lung". while it is common for creationist and birds-came-first-ist literature to group these two together, this would be a fundamental misunderstanding of evolution. it does not work in an all-or-nothing fashion, spontaneous generating whole ("irreducibly complex") systems of organs or organelles. rather, these things come into place piecemeal, and often scaffold. it is quite possible to have a partially avian respiratory system, without abdominal air sacs, or any of the other peculiar skeletal formations tied to the respiratory systems of modern birds. want proof? here's another animal that swings its femora even more widely, and has a lung similar to birds.
quote: get that one? crocodiles, more or less, have the same respiratory system as birds. neither crocodiles nor ratite birds collapse a lung when they run, and crocodiles have a completely different method of locomotion and skeletal arrangement. rather, it seems that avian flight condition evolved around and already developed respiratory system, which then became more reliant on specific adaptions for flight. these have secondarily lost in some flightless birds, such as ratites. in fact, we find that many theropod dinosaurs, specifically the maniraptors, do indeed have partially pneumatized bones, and to about the same degree as modern ratites. this means velociraptor and even t. rex had thoracic and abdominal airs sacs, like flying birds -- just in a reduced capacity. simple enough. something like the crocodilian lung existed in all dinosaurs, and progressed towards the avian lung in theropods. in flying dinosaurs, the air sacs simply greatly expanded, co-evolving with greater and greater flight capability. the earliest flying dinosaurs were not capable of extended powered flight, due in large part to their small sternums. they simply lacked the musculature. as they began to gain this musculature, they made a trade-off: more focus on flight, less on the ground. this trade-off allowed greater expansion of the abdominal air sacs -- but might have limited locomotion on the ground. this is not a problem for the dinosaurian evolution of birds. not in the slightest. Edited by arachnophilia, : No reason given. Edited by arachnophilia, : additional article Edited by arachnophilia, : sorry for the repeated and massive edits, but the more i look at this, the more the whole idea of the necessity of a restricted femur in any avian due to paradoxical collapse of the posterior air sacs.. is just a giant load of bullshit, all put forward by this one particular paper, quick & rubens (2009), with no real basis in anything. please see this blogpost for a strong critique: Page not found | ScienceBlogs
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arachnophilia Member (Idle past 1370 days) Posts: 9069 From: god's waiting room Joined: |
faith24 writes: You know, people always thought that birds evolved from dinosaurs. you have misunderstood. and so have perhaps a few members of this forum. birds did not "evolve from" dinosaurs. birds are dinosaurs. in the same way that a lizard is a reptile, or a frog is an amphibian, or you are a mammal. birds are dinosaurs. they are a highly specialized sub-group, but not a separate group.
Some suggest that the Archeopteryx is just a perching bird. picture time! (source) that should settle it, right? not just a bird, much more like a dinosaur.
There are huge differences between birds and dinosaurs that it is impossible for birds to evolved from dinosaurs. no. birds are dinosaurs. birds are highly specialized, yes. most of that specialization is in the form of ossification between bones, such as the digits becoming the carpormetacarpus. but many birds, such as rarites, retain some of the dinosaurian digits, and some, like the hoatzin, are even born with perfect maniraptoran hands, that looks nearly identical to those of a velociraptor.
i'm still confused because there are a lot of misinformation out there you don;t know which one to believe. i suggest reading anything by greg paul.
What do you think about these birds foot print? Geotimes - June 2002 - Bird Fossil Feet i think they're pretty fantastic, don't you?
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arachnophilia Member (Idle past 1370 days) Posts: 9069 From: god's waiting room Joined: |
faith24 writes: This article seem to say otherwise about dino-bird evolution. Maybe it was the other way around?http://www.physorg.com/news184959295.html Taq writes: It is speaking of a single species, microraptor. This doesn't mean that the analysis of this single species applies to ALL dino-bird intermediates. it's talking specifically about pretty much all of dromaeosauridae. there's an interesting idea, and goes something like this: all evidence points to archaeopteryx as being not only the earliest bird known to science, but also the earliest dromaeosaurid. the hyperextensible 2nd digit on the foot is a dead give-away. so, some suggest, that the last common ancestor between archaeopteryx and modern birds was also likely the last common ancestor between archaeopteryx and say velociraptor -- and that something like velociraptor secondarily lost flight. this view is apparently not popular among paleontologists. however, this is not what that article is talking about. it's more "birds came first" nonsense, ala feduccia and co. they basically claim that theropods are not dinosaurs, they're birds, and they've magically converged with dinosaurs to nearly 100% homology. and that's just plain stupid.
There is strong evidence that non-avian dinosaurs had the same type of lung: "Evidence for Avian Intrathoracic Air Sacs in a New Predatory Dinosaur from Argentina" this is actually old hat. a paper like this doesn't show that dinosaurs in general had avian air sacs. we know that they did, and have known for a long, long time. rather, it shows that this particular new find has them. even t. rex had air sacs.
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New Cat's Eye Inactive Member |
There are huge differences between birds and dinosaurs that it is impossible for birds to evolved from dinosaurs. Well I think there's huge similarities! Look at their feets:
quote:you can click on the above pictures to expand them Taken from the OP in a thread I made: Theropods and Birds showing a change in kinds Have a look, I think its worth it, plus there's lots of pictures
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arachnophilia Member (Idle past 1370 days) Posts: 9069 From: god's waiting room Joined: |
Catholic Scientist writes: The emu feet still have scales on them! so, birds have two kinds of scales on their feet: reticulae (on the bottoms, the round reptilian scales) and the scutellae (flat plate-like scales on the top). it turns out that the scutes have a strong relationship to feathers, and lacking a certain protein in development, become feathers. this likely means that birds have one gene that controls feather development all over their bodies, including their feet (such as in microraptor), and another that turns them off in particular places. ie: the dinosaurian scales evolved from feather, not vice-versa.
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New Cat's Eye Inactive Member |
Catholic Scientist writes:
so, birds have two kinds of scales on their feet: reticulae (on the bottoms, the round reptilian scales) and the scutellae (flat plate-like scales on the top). The emu feet still have scales on them! it turns out that the scutes have a strong relationship to feathers, and lacking a certain protein in development, become feathers. this likely means that birds have one gene that controls feather development all over their bodies, including their feet (such as in microraptor), and another that turns them off in particular places. ie: the dinosaurian scales evolved from feather, not vice-versa. Awesome information! Thank you. Its not that hard to imagine scales and feathers as being a variation of the same "thing". I always thought that feathers were just elongated scales but I guess I'll have to change that to some scales just being shortened feathers. I'm gonna add this link to my other thread, thanks again. Where'd the reticulae come from? Fish have scales, but the amphibians don't, and then reptiles do again. Are there any semi-scaly amphibian fossils? I wonder how early the retiples split... I suppose I have some reading to do.
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arachnophilia Member (Idle past 1370 days) Posts: 9069 From: god's waiting room Joined: |
Catholic Scientist writes: Its not that hard to imagine scales and feathers as being a variation of the same "thing". I always thought that feathers were just elongated scales but I guess I'll have to change that to some scales just being shortened feathers. it's important to note that this is not more birds-came-first nonsense. it just shows that perhaps feathers are further down the dinosaurian family tree than previously thought. this has been confirmed recently, with the discovery of an ornithischian dinosaur with primitive feathers. the strong homology between tianyulong's feathers and theropod feathers indicates that feathers probably go back to before the divergence of saurischia and ornithischia. ie: the very earliest dinosaurs might have been walking around sporting similar proto-feathers, and feathers might even be a defining characteristic for dinosaurs (like hair for mammals). of course, they were probably lost secondarily in larger varieties. in any case, i personally feel that feathers probably go back just slightly further than that, perhaps to basal archosaurs, and go hand-in-hand with the evolution of endotherms. for instance, pterosaurs sometimes have "hair" covering their bodies, and iirc, these "hairs" are strongly related to feathers -- they just didn't evolve into the flight surfaces and were strictly used for warmth. also interesting is the fact that crocodiles have scutes. i'm not sure if these are related to feathers in any way, but wouldn't it be truly strange if the basal psuedosuchians were feathered, and the crocodiles lost their feathers secondarily to adapt better to an aquatic environment? i am not a paleontologist, and at least some of these ideas would be very unpopular among actual paleontologists. i'm sure this is partly because they're generally used to support the aforementioned "birds came first" idea, which states that birds evolved in a separate lineage from basal archosaurs (something very lizard-like, actually), and theropods are not actually dinosaurs. which is so stupid, i can't even describe. see the links i posted above. i am very much not supporting this idea, because it stretches convergent evolution to the point of incredulity.
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Buzsaw Inactive Member |
caffeine writes: People came up with the idea that birds evolved from dinosaurs because of the many features that birds share with dinosaurs......... I have long argued that dinos are the pre-fallen/cursed/changed longer legged modern serpent kinds, i.e. reptiles, as per the Genesis record. I point out the many features that dinos share with modern reptiles. My reference to the similarities is consistently rejected by you people. This is a good example of evidence which you consider legitimate in science but disallow as evidence for creationists. BUZSAW B 4 U 2 C Y BUZ SAW. The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future. Time Relates To What Is Temperal. What Is Eternal Is Timeless.
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Dr Adequate Member (Idle past 311 days) Posts: 16113 Joined: |
I have long argued that dinos are the pre-fallen/cursed/changed longer legged modern serpent kinds, i.e. reptiles, as per the Genesis record. I point out the many features that dinos share with modern reptiles. My reference to the similarities is consistently rejected by you people. This is a good example of evidence which you consider legitimate in science but disallow as evidence for creationists. We allow the similarities. But they are not evidence for the Book of Genesis because they are not predictions of that work.
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jar Member (Idle past 420 days) Posts: 34026 From: Texas!! Joined: |
Buz writes: I have long argued that dinos are the pre-fallen/cursed/changed longer legged modern serpent kinds, i.e. reptiles, as per the Genesis record. I point out the many features that dinos share with modern reptiles. My reference to the similarities is consistently rejected by you people. This is a good example of evidence which you consider legitimate in science but disallow as evidence for creationists. As pointed out in Message 24 many years ago, there is additional support for the GOE Fallen Serpent loosing its voice saga.
quote: Anyone so limited that they can only spell a word one way is severely handicapped!
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PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
quote: By which you mean according to your OWN version of the Eden myth, since the actual story places the curse on a single individual and its descendants and does not include a partial version of the curse being placed on anyone, let alone hundreds or thousands of species.
quote: But not the differences which convince taxonomists that snakes are NOT descended from dinosaurs at all. Nor do we ignore the fossil evidence contradicting your hypothesis - as you do.
quote: Of course you are wrong here. The evidence of a relationship IS accepted as evidence of a relationship. It is NOT however accepted as evidence sufficient to establish snakes as descendants of dinosaurs - and I have no doubt that you would be quick to agree with that assessment if it were convenient for you. And that's on top of the evidence you ignore - or the fact that you have needed to make ad hoc additions to the myth to even accommodate the fossil evidence that you have accepted. So be honest Buz and accept the fact that your evidence is hopelessly weak and the evidence against your hypothesis is very strong. And THAT is why your silly hypothesis is rejected.
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Buzsaw Inactive Member |
PaulK writes: But not the differences which convince taxonomists that snakes are NOT descended from dinosaurs at all. Nor do we ignore the fossil evidence contradicting your hypothesis - as you do. There you go, obfuscating my position. I've explained this before more than once, but I'll explain it again. Dinos are reptiles.Snakes are reptiles. Serpents are reptiles The only word in the manuscripts of the Genesis record for snakes, dinos, lizards, iguanas, alligators etc is serpent. Appearances of heads, tails etc share a common appearance. Bottom line; the similarities of modern reptiles and dino reptiles are extremely more numerous than the similarities of birds and dinos, yet (abe: the conventional science world disallows the more similar types). This is why the less likely hypotheses are funded, taught, peered and researched in the science arena. Edited by Buzsaw, : Noted in context. BUZSAW B 4 U 2 C Y BUZ SAW. The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future. Time Relates To What Is Temperal. What Is Eternal Is Timeless.
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DrJones* Member Posts: 2290 From: Edmonton, Alberta, Canada Joined: Member Rating: 6.9 |
yet the SM allows for the less similar but disallows the more similar.
Buz, what is "the SM"? It's not enough to bash in heads, you've got to bash in minds soon I discovered that this rock thing was true Jerry Lee Lewis was the devil Jesus was an architect previous to his career as a prophet All of a sudden i found myself in love with the world And so there was only one thing I could do Was ding a ding dang my dang along ling long - Jesus Built my Hotrod Ministry Live every week like it's Shark Week! - Tracey Jordan Just a monkey in a long line of kings. - Matthew Good If "elitist" just means "not the dumbest motherfucker in the room", I'll be an elitist! - Get Your War On *not an actual doctor
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Blue Jay Member (Idle past 2724 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Arachnophilia.
arachnophilia writes: the dinosaurian scales evolved from feather, not vice-versa. This seems highly unrealistic. Scutes clearly predate feathers in the fossil record. I think they even predate the diapsid-synapsid split, so it seems unlikely that feathers predated that. I'm also highly skeptical because apparently none of the cited work by Alan Brush demonstrating that scutes happen when feather development is suppressed were published or peer-reviewed. Also, I'm not sure that a developmental pathway defaulting to a certain end product is really evidence that that end product is the primitive condition. I'm no geneticist, though, so I could be wrong. I could be convinced, however, if they could cause crocodilians to develop feathers instead of scutes using the same techniques. -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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Blue Jay Member (Idle past 2724 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, DrJones.
"SM" stands for "scientific method": I'm not sure where it started, but people were using it in Does ID follow the scientific method? -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
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