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Author Topic:   Theropods and Birds showing a change in kinds
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 9 of 150 (542040)
01-07-2010 10:47 AM
Reply to: Message 6 by slevesque
01-07-2010 10:25 AM


It's the classical case of affirming the consequent:
But you could say that of all scientific knowledge whatsoever.
Besides, any knowledgeable evolutionists should know this, considering the sizeable amount of convergent evolution examples in my biology book ...
But convergent evolution is superficial, it can't be expected to produce similar underlying morphology from lineages that started off different. No amount of convergent evolution will give the hummingbird moth the skeletoon of a hummingbird.
Besides which, I'm not sure that my lifestyle is sufficiently like that of a monkey to produce convergence ... still less the lifestyles of Archaeopteryx and T. rex. The notion that differences in lifestyle have produced divergence seems more plausible.
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 78 of 150 (545547)
02-04-2010 7:44 AM
Reply to: Message 67 by slevesque
02-03-2010 3:10 PM


Re: Feathers as novel features
A lot of the criticism I read yesterday by Alan Feduccia were very interesting and I think a little research on what he has to say would be helpful. I'll try to find some bits to put here.
Here's one to start you off:
Creationists are going to distort whatever arguments come up, and they've put me in company with luminaries like Stephen Jay Gould, so it doesn't bother me a bit. Archaeopteryx is half reptile and half bird any way you cut the deck, and so it is a Rosetta stone for evolution, whether it is related to dinosaurs or not. These creationists are confusing an argument about minor details of evolution with the indisputable fact of evolution.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 79 of 150 (545553)
02-04-2010 8:15 AM
Reply to: Message 72 by slevesque
02-03-2010 5:16 PM


There exists no half dinosaur/half bird fossils.
What, in your opinion, is Archaeopteryx, then? Chopped liver?
And I have already mentioned that birds appear before their supposed ancestors in the fossil record ...
If you think about that statement for a moment, you will see that it can't possibly be true. Biologists, you see, know quite a lot about biology, and this means that none of them supposes that birds lived before their ancestors.
Add to that the fact that there are a lot of fake dinosaur-bird fossils out there coming from china ...
Which paleontologists can spot, which is the only reason you know that in the first place.

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Replies to this message:
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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 81 of 150 (545557)
02-04-2010 9:11 AM
Reply to: Message 80 by Huntard
02-04-2010 8:56 AM


To be fair to Slevesque, he did say supposed ancestors.
And to be fair to biologists, they suppose no such thing.
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 100 of 150 (545699)
02-04-2010 9:09 PM
Reply to: Message 91 by slevesque
02-04-2010 3:51 PM


Re: Feathers as novel features
Yeah I have read some counter-quotes by Feduccia when searching a bit yesterday. I think it is fairly obvious thatwhat happened to him is the same that happened to Gould. He thought of a great alternative to the commonly accepted theory and started out in fanfare trying to promote it, with big claims etc. Of course, when some of those claims were picked up by creationists it hurt his reputation quite a bit, and to claim it back he stepped down a notch on his claims and even contradicted himself on some occasions, such as here. (which was an email answer to a question by a layman, I believe right ?)
In any case, he contradicts himself. It's normal with humans
I think what hurt his reputation was being wrong. How much attention do you think the average biologist pays to creationists?
In what way do you think he contradicts himself?

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 101 of 150 (545701)
02-04-2010 9:18 PM
Reply to: Message 92 by slevesque
02-04-2010 3:56 PM


Did you read the interview with Feduccia I posted earlier ? He says that there are loads of fake fossils out there. Obviously, if they were easy to spot they wouldn't be 'out there'.
I didn't say it was easy, I said that paleontologists can do it. Tourists visiting China and looking for souvenirs mostly can't.
Or do you think only archaeoraptor was fake and all the others were legit ?
Can you name any other fake primitive bird from China that managed to temporarily fool a couple of paleontologists?
So far as I know, no primitive bird fossil that has got into the scientific literature has subsequently been exposed as a "Piltdown bird". If you know better, let me know.
And if this had happened, you would know about it, would you? Because creationists, who would have played absolutely no role in uncovering the hoax, and not one of whom could tell a real fossil from a fake fossil from a hole in the bleedin' ground, would never shut up about how this proves that all biologists are stupid and EVIL-UTION IS A LIE OMG!!!

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 102 of 150 (545705)
02-04-2010 9:43 PM
Reply to: Message 94 by slevesque
02-04-2010 4:03 PM


But in the case of fossils, you have either dinosaurs with feathers, but aside from that are completely dinosaurs.
Oh, come, on paleontologists find dinosaurs with feathers and you just brush it off?
Suppose that they had not yet found any such thing? Wouldn't you be making a big deal out of it?
And birds with all the characteristics of birds ...
Archaeopteryx does not in fact have all the characteristics of modern birds.
---
The problem with this, as with every similar creationist attempt at shoehorning, is that the extremal members of the two groups thus artificially constructed are closer anatomically then they are to other members of "their own" groups.
A coelurosaur such as Compsognathus is much closer anatomically to Archaeopteryx than it is to another theropod dinosaur --- T. rex, for example. And Archaeopteryx is much closer anatomically to Compsognathus than it is to, for example, a sparrow (or any other living bird, for that matter).
Or to put it another way, if Archeopteryx is a bird, and Compsognathus is a dinosaur, then Archaeopteryx is a bird with almost completely dinosaurian features (since it's almost exactly the same as Compsognathus), and Compsognathus is a dinosaur with almost exclusively avian features (since it's almost exactly the same as Archaeopteryx).
Placing the division where you do therefore has nothing to do with anatomy and everything to do with the creationist need to draw a line somewhere. Anywhere.
No really 50/50 in between type. No in between lung structure, no in between femur structure, no in between balance structure, etc.
Perhaps you could elaborate on this.
* Lungs: the evidence shows that dinosaurs had the same sort of lungs as birds. Why should there be something "in between" two structures which are identical?
* Femurs: well, since you've decided that Archaeopteryx is a bird, and that coelurosaurs are not, could you explain to us what the anatomical difference is between the femurs of the two? If there isn't any, then my remarks about lungs apply.
* Balance structure: I don't know what you mean, please explain. And, again, will you please let us know if Archaeopteryx, which you deem a bird, really has a different "balance structure" from a coelurosaur.
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.

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Replies to this message:
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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 103 of 150 (545717)
02-04-2010 11:47 PM
Reply to: Message 90 by slevesque
02-04-2010 3:40 PM


Re: Feathers as novel features
Ever seen baby ostriches covered with downy feathers ? Quite cute right, but now imagine it getting all wet. It will die of hypothermia within minutes if it's mother doesn't heat it up. For a species to be covered by such a structure for endothermy would be extremely maladaptive, to the point of being harmful.
So, the omniscient creator really screwed up by giving baby birds down, eh? Either that or he's just trying to kill as many cute little dicky-birds as possible.
Or, just possibly, you don't know much about birds.
You do not explain why the same dreadful fate does not befall the adult ostrich when she gets wet. Is there something in particular which makes wet down a poorer insulator than wet feathers? Or why either should be inferior to naked skin?
And of course, no dinosaurs are found with downy feathers. They are either found with 'dinofuzz' or with true feathers which have a central rachis, etc.
But see here.
In fact, the dinofuzz is found not only on therapods, but also on icthyosaurs, pterosaurs and ornithischian dinosaurs. In none of these cases are they related to feathers, and there is nothing to suggest then that this should be the case with therapods.
And, for some reason which you can't quite explain, the mere existence of therapods with feathers doesn't support a link between therapods and birds.
Convergent evolution can do marvels. Exactly the same sonar structure up down to the genome level in dolphins and bats, for example.
The value of your example is vitiated by being totally made up.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 105 of 150 (545730)
02-05-2010 12:56 AM
Reply to: Message 104 by pandion
02-05-2010 12:37 AM


Three Ring Czerkas
My bet is that he can't name any fake, primitive bird from anywhere that fooled paleontologists. Archaeoraptor did fool a few amateurs, but the first qualified paleontologists who examined the fossil recognized it as a fake at first glance. They proved it with CT scans and concluded that the fossil was composed of 3 to 5 separate fossils.
One sad thing, the forward part was of a previously unknown primitive bird, while the hind part was from a previously unknown maniraptorian, theropod dinosaur.
In short, Archaeoraptor didn't fool any qualified paleontologist.
You're quite right, my bad. The Czerkases weren't professional paleontologists, nor had they ever received any formal training in the subject. They were dinosaur artists.
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 109 of 150 (545797)
02-05-2010 12:21 PM
Reply to: Message 107 by caffeine
02-05-2010 9:56 AM


Re: Phylogenetic nitpick
Tyrannosaurs are coelurosaurs, just slightly more distantly related to birds than compsognathids.
True ... and yet doesn't that make my point even pointier? Which really looks like the odd one out --- Tyrannosaurus, Compsognathus, Archaeopteryx? I have to go with Tyrannosaurus.
So I guess what I should have said is: "A maniraptor such as Compsognathus is much closer anatomically to Archaeopteryx than it is to another coelurosaur --- T. rex, for example."

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Replies to this message:
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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 110 of 150 (545799)
02-05-2010 12:58 PM
Reply to: Message 106 by caffeine
02-05-2010 9:49 AM


Anchiornis
Many dinosaurs have been found with downy feathers — all oviraptoriformes seem to have possessed at least some, and there’s a new taxon reported in Nature last year which not only seems to have possessed downy feathers, but also appears to be a maniraptoran theropod from before Archaeopteryx.
Your link isn't working for me --- are we thinking of the same article? "A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus"?
Yes, Anchiornis is a pre-Archaeopteryx maniraptor. So either the creationists will have to abandon an argument merely because it's been proved totally wrong --- or, and this is what I'm guessing, they'll decide to classify a non-avialan dinosaur as being a bird with nothing dinosaurian about it at all. Or perhaps they'll impute that it's a fake without offering a scrap of evidence for this. Or they'll attack the dating methods in which they seemingly put implicit trust before the temporal paradox was resolved by the application of those exact same methods to the new fossils. Or ...

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 127 of 150 (545861)
02-05-2010 7:29 PM
Reply to: Message 122 by slevesque
02-05-2010 4:54 PM


We got lucky with archaeoraptor since Xu Xing happened to see a part of it's original species in a private collection.
The only solution is that the publishers require CT scans on every fossil coming from china before publishing it.
In the first place, that isn't the only reason. Another reason is that Tim Rowe did in fact do a CT scan and find problems with the fossil.
And the scientific journals did in fact refuse to publish the papers they were sent.
What we have here is an example of how science works, how the peer-review system works, how amateurs should defer to the professionals, and how paleontologists know what they're doing.
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 128 of 150 (545863)
02-05-2010 7:38 PM
Reply to: Message 113 by slevesque
02-05-2010 4:00 PM


Re: Feathers as novel features
Because he argues elsewhere that archaeoptryx was a perching bird. (which is the correct anatomical conclusion) which is in a contradiction of his half bird/half dinosaur quote you posted earlier.
I think you're splitting hairs. It was a perching bird, by definition of the clade of birds (and perching because I believe the consensus view is now that it had a reversed hallux). It is also an intermediate between dinosaurs and modern birds.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 131 of 150 (545877)
02-05-2010 8:56 PM
Reply to: Message 116 by slevesque
02-05-2010 4:22 PM


Maybe because Compsognathus, as archaeopteryx, was a perching bird ?
So you're now going to draw the line between birds and dinosaurs so that this is included with the birds?
But don't you see, this leaves you with exactly the same problem. Compsognathus is more like some animals on the dinosaur side of the line than it is to other members of the bird group you'd like to lump it in with. Heck, it's even more similar to some non-dinosaur archosaurs than it is to a modern bird.
Here's Lagosuchus. This saurian isn't even classed as a dinosaur.
And this, slevesque, is a chicken.
Everyone join in the song ...
If Compsognathus and other maniraptors are birds, but the other coelurosaurs are not, then the maniraptors are birds with almost completely coelurosaur features, and the other coelurosaurs are dinosaurs with almost entirely avian features.. You want to throw in the coelusrosaurs as birds, but say that the other therapods are not? Very well then, the coelurosaurs are birds with almost entirely therapod features, whereas the therapods are dinosaurs with almost completely avian features ... and this is going to happen wherever you draw the line. Are you going to keep going until you've decided that all therapods are birds? That all dinosaurs are birds? And then I'm going to make you start throwing non-dinosaur archosaurs in as well. Are you going to drag the crocodiles into this too? Where would you like to stop?
I don't know where you get this. Alleged feathered dinosaurs such as Sinosauropteryx have bellowslike lungs which are very different from avian lungs.
Hold on, hold on. Stop right there. Wait just one darned cotton-picking minute. According to your link to Ruben et al, which you kindly provide in a subsequent post, Archaeopteryx and other primitive birds had just the same sort of lungs as dinosaurs. And Archaeopteryx, you say, is a bird. So we don't need to find a transition between the lungs of dinosaurs and birds, because the most primitive birds had the same sort of lungs as dinosaurs.
I may have more to say about lungs later, I'll have to look some stuff up.
I don't know the lung structure of Coelurosaurs. I know that birds have fixed femurs inside there body because if they didn't there lungs would collapse. I also know that therapods did not.
I know the paper you're basing this on. I also know what else, according to that same paper, didn't have fixed femurs. Can you guess what?
That's right. Archaeopteryx.
Let me quote from the paper (Quick and Ruben, 2009):
Many of these skeletal specializations are not apparent in the earliest birds, including Archaeopteryx, confuciusornithine or enantiornithine birds (Hillenius and Ruben, 2004a). Their presence is also questionable in even Early Cretaceous ornithurines but well developed in the Late Cretaceous hesperornithiform birds (Hillenius and Ruben, 2004a). The femur most likely did not attain its subhorizontal position until the Late Cretaceous in ornithurines as indicated by the presence of the antitrochanter...
And what's Archaeopteryx? It's a bird. You said.
So we don't need to find a transition between dinosaur femurs and bird femurs because the most primitive birds have the same sort of femurs as dinosaurs.
I mean that shortened forelimbs and heavy, balancing tails isn't quite the good anatomy for flight. Birds centre of mass has to be well balanced in order for flying to be possible. This applies to archaeopteryx.
And let's do this one more time. Archaeopteryx has a long bony tail. Like a dinosaur. And what did you say Archaeopteryx was, remind me? Oh yes, it's a bird.
So we don't need to find a transition between the tails of dinosaurs and the tails of birds, because the most primitive birds have just the same sorts of tails as dinosaurs.
You might, perhaps, ask for transitions in the tail between primitive and modern birds, and unless my memory has gone completely haywire, there are plenty.
Are you sure you wouldn't now like to classify Archaeopteryx as a dinosaur?
Well, that's why they call them intermediate forms.
I find little information on the net concerning Coelurosaurs, so you'll have to tell me.
I'll come back to that in a subsequent post ... this one, I feel, is quite long enough.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 133 of 150 (545883)
02-05-2010 9:56 PM
Reply to: Message 116 by slevesque
02-05-2010 4:22 PM


I find little information on the net concerning Coelurosaurs, so you'll have to tell me.
Specifically, let us consider the compsognathidae, Archaeopteryx, and modern birds.
Now, in the following series, which I prepared for an article I wrote, I have not always been able to use the same compsignathid and the same modern bird, because I had to go with what I could find. On my word of honor, however, I have not in any way cherry-picked the compsognathids and the modern birds to make my point.
In all these pictures, the order, either from top to bottom or from left to right, is: compsognathid, Archaeopteryx, modern bird.
Let's start with the skulls, shall we?
Now some pelves:
You should also note that in modern birds the pelvis is fused to the adjacent vertebrae, a fact which is not shown on this diagram.
Now the manus. Note that these have been rescaled to be the same length. I didn't do that, it's how I got 'em. You'll be able to see the true proportions in the next picture on.
And now let's take an overview of the entire skeletal anatomy:
Some point of interest:
* The tail. In the modern bird, this has been reduced to a pygostyle.
* The large keeled breastbone of the modern bird.
* The synsacrum --- that's the plate of bone on the back and to the rear of the modern bird, formed by fusion of ribs.
* The gastralia or so-called "abdominal ribs" --- the fine structures along the belly of the dinosaur (Compsognathus) and Archaeopteryx.
* The femurs. In the modern bird, as mentioned in my previous post, these are fixed in a near-horizontal position.
Now, we could go on to discuss the finer details, or we could just sing along with the Cookie Monster:
So, do you want to declare Compsognathus a bird, or do you want to declare Archaeopteryx a dinosaur, or ... I don't suppose you'd like to bow to reality and admit that you're wrong, would you?
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.

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