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Author Topic:   Archaeopteryx and Dino-Bird Evolution
AdminNosy
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Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 16 of 200 (250579)
10-10-2005 9:18 PM
Reply to: Message 15 by jar
10-10-2005 9:13 PM


Inadequate support for an assertion
Crap
Well, obviously.
However, it is probably that it isn't obvious to Springer so you will have to support your assertion with some detail aimed at his specific statements.

This message is a reply to:
 Message 15 by jar, posted 10-10-2005 9:13 PM jar has replied

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jar
Member (Idle past 394 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 17 of 200 (250581)
10-10-2005 9:20 PM
Reply to: Message 16 by AdminNosy
10-10-2005 9:18 PM


Re: Inadequate support for an assertion
Okay
Total and unmitigated Crap!
I'm sorry but Springer claims that he is a Physician. As such I expect at least a basic understanding of science and logic.

Aslan is not a Tame Lion

This message is a reply to:
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AdminNosy
Administrator
Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 18 of 200 (250583)
10-10-2005 9:23 PM
Reply to: Message 17 by jar
10-10-2005 9:20 PM


Re: Inadequate support for an assertion
Sure. But if you don't want to bother pointing out the errors then you should just not respond. Responding requires you to put more effort into it.
I don't think he's worth responding to and don't believe he has enough understanding of any form of reasoning to get it anyway. So I don't bother to post anything.

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Nuggin
Member (Idle past 2492 days)
Posts: 2965
From: Los Angeles, CA USA
Joined: 08-09-2005


Message 19 of 200 (250621)
10-11-2005 1:40 AM
Reply to: Message 14 by Springer
10-10-2005 9:01 PM


Re: archaeopteryx is not transitional
So, let me get this straight. Your argument is that Archie had fully formed flight feathers, and therefore despite have lizard-like head, hips, tail, etc. It was a bird.
You must admit that it doesn't look much like a eagle.
Can you name me some birds with lizard heads? I can't think of any off hand.
Let's get back to transition, shall we? What would make you happy with dino-bird transition? A dino-lizard with symetrical (non-flight) feather? How about one with downy feather? How about one with flight feathers and a beak, but still lizard hips?
What is required for you to believe there is a transition? If Archie is too bird, set a mark, we'll hit it.

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Parasomnium
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Posts: 2224
Joined: 07-15-2003


Message 20 of 200 (250632)
10-11-2005 3:03 AM
Reply to: Message 14 by Springer
10-10-2005 9:01 PM


Re: archaeopteryx is not transitional
Springer writes:
The problem with evolutionists is that they minimize the need for transitional species, when the ToE demands literally millions of them in the past.
Springer, may I suggest you take a look at this thread? Your input would be welcome, provided it addresses the argument I put forward there.

We are all atheists about most of the gods that humanity has ever believed in. Some of us just go one god further. - Richard Dawkins

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arachnophilia
Member (Idle past 1343 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 21 of 200 (250639)
10-11-2005 4:04 AM
Reply to: Message 14 by Springer
10-10-2005 9:01 PM


archaeopteryx is VERY transitional
In its most important feature, namely flight feathers, archaeopteryx is no less of a bird than modern birds.
in its feathers, yes.
If it were alive today, it would be classified as a bird.
this is not true, and obvious to just about everyone, including its early creationist detractors. they argued that archaeopteryx was a forgery -- comprised of the skeleton of a compsagnathus with faked feather impressions. why? because if we take away the feathers for a second, archaeopteryx only looks remotely like a bird, but much more like a small theropod:
here's a chicken for comparison:
its skeleton has far too many features in common with small theropod dinosaurs for it to be a true bird, in the modern sense. let's look at a few of them, shall we?
archaeopteryx not only has teeth, but lacks a bill. there is no hard covering on the end of its snout. it has a skull much like that of a theropod. it also has a long tail, which has not fused into a bird's pygostyle. this indicates that it probably had a level posture like most theropod dinosaurs, not the more upright posture of modern birds -- it wouldn't balance or walk like a bird.
the complete lack of anything like a pygostyle is kind of interesting, actually. several small theropod dinosaurs, the dromeosaurids, have the tips of their tails fused by long extensions of the vertebral bones. archaeopteryx is curiously LESS avian than say velociraptor in this respect.
But there is no evidence that it wasn't as powerful a flyer as a modern bird.
considering that archaeopteryx has a tiny sternum, and lacks the predominant breastbone and keel of modern birds, it would have been flat-out incapable of powered flight -- at all. it has no bone with which to attach the enormous flight muscles required to generate lift. it could flap its arms, but so could dienonychus. neither would have gotten off the ground with it, even with feathers. this isn't dumbo, and feathers are not magic.
heck, even the chicken above would be more capable of powered flight than archaeopteryx, and we all know chickens don't fly for any substantial length of time.
By the way, three living birds today have claws on their wings and are still considered true birds.
let's make no bones about this, because this is a major difference. archaeopteryx does not have a true wing. it's claws are on a HAND, not a wing. in modern birds, the wing bones are thick, formed of fused digits 2 and 3. archaeopteryx has 3 individual slender digits. in its legs, it has a full fibula, extending all the way to ankle, and has a fifth toe. modern birds do not have a fifth toe, and their fibulas stop about halfway down the tibia. theropod dinosaurs, however, have all five toe and a full fibula.
archaeopteryx is, in almost every respect, a small theropod dinosaurs. so what makes it a BIRD, exactly? feathers, obviously. aside for that, it has very avian hips (as do the dromeosaurids), the half-crescent wrist bones (as do the dromeosaurids), a wishbone (fused clavicles), hollow bones, an opposed hallux (1st toe), and arms that are at least the length of its legs.
basically, calling a bird isn't exactly right. it's a theropod dinosaur in nearly every respect, with a few very key bird features that are really only seen upon close examination. it is quite a genuine mix, but if i were classify it as one or the other, it would definitally still be a dinosaur.
If archaeopteryx is the best evolutionists can come up with for transitional forms, their argument is weak indeed.
considering that archaeopteryx is exactly what we would expect to find to fid for a theropod-bird transition, and the fact that that transition is ALREADY strongly backed by numerous other dinosaurs, feathered or not, i would say the argument is very strong.
it would be very strong even without archaeopteryx or any other feathered dinosaurs. ornithologists have knows for 100 years or more that birds came from archosaurs, though not through dinosaurs. they were able to identify various archosaur features in birds. when the first dinosaurs skeletons were found, it was believed that birds came from the various "bird-hipped" dinosaurs, such as the ceratopsians (which, btw DO have beaks and quite bird-like hips). and when dienonychus was found, with its bird wrist bones, bird-like feet, fused tail vertebrae, long arms, and backward-turned "lizard hip" that nearly matches todays today's birds, well, the case pretty much closed.
The problem with evolutionists is that they minimize the need for transitional species, when the ToE demands literally millions of them in the past.
i should scan some of these diagrams from the book i'm currently perusing on the subject. one, for instance, shows the hip bones of the major families of dinosaurs throughout the entire mesozoic era. the progression of the saurischian pubis steadily backwards until you reach dienonychus and archaeopteryx is kind of startling. every group they mention, sauropods to ceratosaurs to allosaurs, to tyrannosaurs and ornithomimosaurs, to dromeosaurs -- they're ALL transitional. and when you stick a modern bird's hip on the end of the diagram, you have to spend a few minutes looking for the differences between it and the dromeosaurs. one wonders why they even bothered putting it on, it's barely any different.
no, we're not minimizing the need for transitionals. some of us have seen enough of these specimens to notice the transitions in just about everything, even if some are dead-ends.
My suggestion is to stop fixating on one or two questionable examples and look at what the present and the past show... that nature is fundamentally discontinuous.
we're not fixating on one or two examples. there are over a dozen feathered dinosaurs we've found, and they butt up and cross into early birds pretty well. the late cretacious theropods show lots of avian features across the board.
we talk about archaeopteryx because it's an example everyone's heard about, and generally considered the clincher to the debate. it's the particular example the creationists are asking for, but still reject upon seeing. it's clearly part bird, part dinosaur, maybe 40/60. we also talk about because it's not SUBTLE in it's transitional nature. it doesn't look like one or the other.
now, if you wanna discuss this little guy, be my guest:
sinornis has a pygostyle, and its metatarsels are partially fused. please note, PARTIALLY fused, as in not fully one or the other. it has the sternum of a bird, but not the keel. it's 2 and 3 digits in the hand are fused into a modern wing, but it has a theropodal-style head with teeth and lacks a bill. overall, it looks like a bird, not a dinosaur. it's differences are a little more subtle. if we saw one flying around today, no doubt we'd think it was a bird, not a dinosaur, until we saw its head.
but until the creationists get the bluntly obvious down about archaeopteryx, there's little point discussing the finer details of the ones a little further along the transition.
There are enormous differences between birds and reptiles, and it would have required at least tens of thousands of functional transitional forms to bridge the gap. You suppose that they existed but you have no proof and you can't even construct hypothetical intermediate forms.
wanna try this one again? as i've spelled out above, we have nearly every major feature of modern birds figured out in terms of origin. we know how each and every "hypothetical" step of feather development came about. i use quotes because we have an example of a feathered dinosaur species representing nearly every single one of them. we know how flight evolved, as an extension of the maniraptorian grasping action, and have the crescent wrist bones of velociraptor to prove it.
the supposed lack of intermediate forms exists only within the creationist's head. they refuse to see the blindly obvious -- that a theropod with a few bird features and feathers is transitional. how are we to expect them to see the more subtle commonalities between other forms?
I've noticed a conspicuous lack of illustrations in the literature of transitional species of, for example, between reptiles and birds,
you're not looking the right place. i checked out three encyclopedia-volume-sized books on this tonight. i rejected a fourth, larger one, which was totally about mesozoic birds because i was looking for illustrations of reconstructions -- not photos of the individual bones from various views.
i might note that these were pop-sci books. i didn't even bother going to the technical journals on the matter.
This is because evolutionists prefer to speak in very vague terms, glossing over critical details.
does what i wrote above sound like i'm glossing over details? i'll scan some illustrations if you'd really like. it's the creationists that can't seem fathom the vague and the obvious -- so why should we go into the technical?
They know perfectly well that any attempt to actually visualize a functional transitional forms that would preferentially survive by natural selection would be so laughable that all credibility in ToE would plummit.
yet there are two of them, right above. want some more? i'll post some more. creationists have this wonderful notion that transitionals don't exist because they can't be functional. what good is half a wing, right?
ask archaeopteryx. he has half a wing: feathers, but not wing bones. what did he use it for? was it an aid in running? did he glide from trees? these are sort of like flying, aren't they? good half-way points. maybe they were sexually selected for. what use does a peacock's tail have? certainly, it's not functional in any respect.
i think you fill find that if you go to a university library and check out a few good solid books on the matter you find volumes full of functional transitional forms, many of whom survive for a very long time.
edited image size to fix page width- The Queen
This message has been edited by arachnophilia, 10-11-2005 07:40 PM

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arachnophilia
Member (Idle past 1343 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 22 of 200 (251467)
10-13-2005 2:03 PM


metatron -- read this post
i read your pnt, but we've currently got three dino-bird threads going on. one about the respiratory system, one about archaeopteryx as an example of the transition, and one about a new raptor reported today. i think this would be a good place to discuss tails, since archaeopteryx has one.
there's one simple problem with argument: all theropods are carnivorous, and the ones birds came from are probably all predatory, too. animals like the new raptor found today are basically well oiled killing machines.
and they're designed for speed, speed, and speed. simple dinosaur biology holds that the tail is used as counterbalance to the body, so the dinosaur can walk upright easily (or hold its head up, in the case of sauropods). they probably were used to help steer at high speeds, yes. and feathers would have certainly helped. but i don't think they evolved to run AWAY from something, even if they would have helped in extenuating circumstances. but the argument for flight feathers as extension of rudder-like tail feathers is a good one.

אָרַח

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Chiroptera
Inactive Member


Message 23 of 200 (251469)
10-13-2005 2:10 PM
Reply to: Message 14 by Springer
10-10-2005 9:01 PM


Re: archaeopteryx is not transitional
quote:
If it were alive today, it would be classified as a bird.
Archaeopteryx is a bird only because scientists have decided that they will make the definition of Aves broad enough to include Archaeopteryx. The boundaries of the classifications are artificial, and in this case they are arbitrarily placed so as to include Archaeopteryx.

"Intellectually, scientifically, even artistically, fundamentalism -- biblical literalism -- is a road to nowhere, because it insists on fidelity to revealed truths that are not true." -- Katha Pollitt

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Chiroptera
Inactive Member


Message 24 of 200 (251470)
10-13-2005 2:12 PM
Reply to: Message 22 by arachnophilia
10-13-2005 2:03 PM


Re: metatron -- read this post
Oops. I just wiped out your flag to metatron.
Try putting a message in the topic promotion thread asking a moderator to put a note into metatron's post.

This message is a reply to:
 Message 22 by arachnophilia, posted 10-13-2005 2:03 PM arachnophilia has replied

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arachnophilia
Member (Idle past 1343 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 25 of 200 (251473)
10-13-2005 2:17 PM
Reply to: Message 24 by Chiroptera
10-13-2005 2:12 PM


Re: metatron -- read this post
that's a good idea, thanks

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arachnophilia
Member (Idle past 1343 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 26 of 200 (251491)
10-13-2005 3:21 PM
Reply to: Message 23 by Chiroptera
10-13-2005 2:10 PM


avialae, but not aves
Archaeopteryx is a bird only because scientists have decided that they will make the definition of Aves broad enough to include Archaeopteryx. The boundaries of the classifications are artificial, and in this case they are arbitrarily placed so as to include Archaeopteryx.
i guess you called me on one so i get to call you one. the books i have place archaeopteryx in avialae, but not aves. it has something like this:
  • maniraptora
    • dromeosauridae
    • avialae
      • archaeopteryx
      • ornithurae
        • mononykus
        • ornithothoraces
          • enantionithes
          • carinatae
            • hesperonoris
            • ichthyornis
            • aves (modern birds)
              • paleognathae
              • neognathae
This message has been edited by arachnophilia, 10-13-2005 03:29 PM

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Chiroptera
Inactive Member


Message 27 of 200 (251496)
10-13-2005 3:38 PM
Reply to: Message 26 by arachnophilia
10-13-2005 3:21 PM


Doh!
Heh. I have seen that classification scheme, too, so perhaps I shouldn't have been so quick with my fancy scientific terminology.
This does sort of support our points, though (notice me making lemonade?): if one arbitrarily only considers Aves to be birds, then Archaeopteryx is then not a bird. If, on the other hand, all the members of Avilae have the features that we naturally want to associate with birds, then Archaeopteryx can be considered a bird.
What is and is not a bird is rather arbitrary (like most definitions), and unfortunately for Springer's point, how one classifies Archaeopteryx is less important than the fact that it's classification brings up these issues, just as we would expect from a bird/theropod transitional.
(By the way, I think it is a matter of contention among those who like to be involved in contentions whether Aves should be the crown group of modern birds or the crown group of modern birds and Archie. Since I'm not a biologist or palaeontologist, I don't have a dog in that race.)

"Intellectually, scientifically, even artistically, fundamentalism -- biblical literalism -- is a road to nowhere, because it insists on fidelity to revealed truths that are not true." -- Katha Pollitt

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arachnophilia
Member (Idle past 1343 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 28 of 200 (251499)
10-13-2005 3:56 PM
Reply to: Message 27 by Chiroptera
10-13-2005 3:38 PM


Re: Doh!
Heh. I have seen that classification scheme, too, so perhaps I shouldn't have been so quick with my fancy scientific terminology
it happens. god knows i just did it too, right?
This does sort of support our points, though (notice me making lemonade?): if one arbitrarily only considers Aves to be birds, then Archaeopteryx is then not a bird. If, on the other hand, all the members of Avilae have the features that we naturally want to associate with birds, then Archaeopteryx can be considered a bird.
the bird/dinosaur line is kind of fuzzy. technically, all birds are theropod dinosaurs -- but technically we're also reptiles, right? there is a distinct set of features that makes a bird a bird, just like there's a distinct set of features that makes a mammal a mammal. but in the transition areas, we would expect those to be fuzzy. some features would be present, some would not:
What is and is not a bird is rather arbitrary (like most definitions), and unfortunately for Springer's point, how one classifies Archaeopteryx is less important than the fact that it's classification brings up these issues, just as we would expect from a bird/theropod transitional.
and this is exactly what we see in archaeopteryx. it's not a bird, in my opinion, because it fails to possess a significant portion of those specific features. i would call it a feathered, avian dinosaur. but not a bird.
(By the way, I think it is a matter of contention among those who like to be involved in contentions whether Aves should be the crown group of modern birds or the crown group of modern birds and Archie. Since I'm not a biologist or palaeontologist, I don't have a dog in that race.)
yes, i notice that cladogram is different than mine. it's puts aves much higher, which i don't really agree with. that one does place archaeopteryx into aves. it's not so much that i have a dog in the race, i just think it makes a lot more sense the other way.
ah well, it's all arbitrary anyways, right? shall we debate this minor technicality?

אָרַח

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 Message 29 by Chiroptera, posted 10-13-2005 4:13 PM arachnophilia has replied

  
Chiroptera
Inactive Member


Message 29 of 200 (251503)
10-13-2005 4:13 PM
Reply to: Message 28 by arachnophilia
10-13-2005 3:56 PM


Re: Doh!
quote:
technically, all birds are theropod dinosaurs -- but technically we're also reptiles, right?
I was writing from the stand point of traditional taxonomy, which recognizes paraphyletic groupings. Not all biologists, or even all systemists, have yet adopted an entirely phylogenic approach to classification, so I will switch from one to the other as it is convenient for me. Bad habit on my part: it does open the possibility of equivocation.
As far as whether mammals are descended from reptiles (or are reptiles or whatever) -- as I mentioned, I don't like that. I've read that the last common ancestor of modern reptiles and mammals was early enough that it still had many amphibian characteristics. I would assume, then, that as the line that led to reptiles further evolved their distinctive reptilian features, the synapsids would have evolved in a different direction (unless there was some sort of convergent evolution). Of course, on can define (and people did and probably still do) define reptile in such a way to include synapsids and therapsids. Me, I prefer to think of reptiles and mammals as closely related but independent lineages of the early tetrapod line. But, not being a biologist, there's no reason for anyone else to accept my musings.
At any rate, even if one does accept that synapsids were reptiles, then whether mammals are reptiles would depend on whether reptile has a place in a completely phylogenic classification -- I don't think it does, I think that Tetrapoda (which, like Aves, has caused some contention as to what it should include) is used instead. I have the impression that reptile is more a taxon in the older scheme that considers it a paraphyletic group. But I could be wrong here, or it could easily change as the schemes change.

"Intellectually, scientifically, even artistically, fundamentalism -- biblical literalism -- is a road to nowhere, because it insists on fidelity to revealed truths that are not true." -- Katha Pollitt

This message is a reply to:
 Message 28 by arachnophilia, posted 10-13-2005 3:56 PM arachnophilia has replied

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arachnophilia
Member (Idle past 1343 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 30 of 200 (251507)
10-13-2005 4:25 PM
Reply to: Message 29 by Chiroptera
10-13-2005 4:13 PM


Re: Doh!
I was writing from the stand point of traditional taxonomy, which recognizes paraphyletic groupings. Not all biologists, or even all systemists, have yet adopted an entirely phylogenic approach to classification, so I will switch from one to the other as it is convenient for me. Bad habit on my part: it does open the possibility of equivocation.
i'm strictly practical, never having a good formalized biology or paleontology education, just a minor interest. so i look at specific features, especially in the hard fossilized parts.
which is why i don't consider archaeopteryx a bird -- it simply doesn't have the skeleton of one. which is the position i described above.
As far as whether mammals are descended from reptiles (or are reptiles or whatever) -- as I mentioned, I don't like that. I've read that the last common ancestor of modern reptiles and mammals was early enough that it still had many amphibian characteristics.
well, yes. birds still have a few reptilian characteristics, and modern reptiles still have some amphibian characteristics. if you look at skeletons only, the all have remarkably similar components.
I would assume, then, that as the line that led to reptiles further evolved their distinctive reptilian features, the synapsids would have evolved in a different direction (unless there was some sort of convergent evolution). Of course, on can define (and people did and probably still do) define reptile in such a way to include synapsids and therapsids. Me, I prefer to think of reptiles and mammals as closely related but independent lineages of the early tetrapod line. But, not being a biologist, there's no reason for anyone else to accept my musings
no, it sounds pretty accurate. we're just quibling over what to call a reptile. it's all the same, really.

אָרַח

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