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Author Topic:   Theropods and Birds showing a change in kinds
caffeine
Member (Idle past 1024 days)
Posts: 1800
From: Prague, Czech Republic
Joined: 10-22-2008


Message 46 of 150 (544890)
01-29-2010 6:19 AM
Reply to: Message 38 by slevesque
01-29-2010 2:33 AM


Feathers as novel features
The issue, for my part at least, I can't speak for every creationists out there, is if there is any evidence of the transitional phases between scales and feathers. Both are very different both on the surface and at the microcospic level I believe, and this type of evidence would be much more compelling for me then a dinosaur with complete feathers.
It is true that scales and feathers are very different structures, and this is why most people who study this don't believe that feathers evolved from scales.
There is evidence, however, of the type of structure feathers are believed to have evolved from, and Sinosauropteryx is one of the dinosaurs we find it in. The ginger structures being discussed aren't true feathers - they lack the barbs, barbules and hooklets of real feathers, which are only found in birds and maniraptoran dinosaurs so far (Sinosauropteryx is a compsognathid, a different type of theropod). These are much simpler, hollow filaments, which were probably the ancestors of true feathers.

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menes777
Member (Idle past 4318 days)
Posts: 36
From: Wichita, KS, USA
Joined: 01-25-2010


Message 47 of 150 (544908)
01-29-2010 11:35 AM
Reply to: Message 36 by slevesque
01-29-2010 1:09 AM


You are right Slevesque
Sorry I probably should have included more info in my post.
I did read what you wrote and I think you make a very good point. I think that we shouldn't base any conclusion on mere physiological similarities. I think it is a good starting point to look for more evidence and then continue to research. Conclusions should only be made when sufficient evidence is collected to support your hypothesis (or beliefs).
Before I go any further, you are arguing for Creation right?

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New Cat's Eye
Inactive Member


Message 48 of 150 (544912)
01-29-2010 12:20 PM
Reply to: Message 36 by slevesque
01-29-2010 1:09 AM


When logical deduction is required to extrapolate a hypothesis from the data, non-fallacious forms of argumentation are rightfully used.
Science works by induction, not deduction. IF: Because only black ravens have been observed, the conclusion is that all ravens are black, and this conclusion is tentatively accpeted until a non-black raven is found. But just because only black ravens have been observed doesn't mean that there isn't a white one that we haven't observed. Its logically fallacious, yet it works.
I raised this issue because CS didn't make the difference between the two and affirmed that, as far as he was concerned, this was sufficient proof of relationship between emu and therapod. Which it is not unfortunately.
Last time you said that, I replied with this (from Message 16):
quote:
I'm not trying to prove it. I'm saying: "Look, here's two different kinds with which you could easily get from one to the other with some microevolutionary changes." Don't you think that's possible?
Don't you think its a good example of the potential ability of one kind to evolve into another?
There's nothing that would prevent a bunch of microevolutionary changes to a theropod from turning it into a bird, is there?
Don't the pictures show that it is at least plausible?
CS's case can be resumed in the following manner:
If you look at an Emu and a Therapod, at first glance they don't look alike at all. In fact you would easily say that they are not of the same kind. But if you pay closer attention, you will start noticing similarities. The feet, the skeleton, even up to the sound, etc. And of course, you figure that you can go from one similarity, the foot for example, to the other through small microevolutionnary changes. Step by step. It's becomes pretty obvious to me that the two are, contrary to first glance, related.
Close enough. In all honesty though, I know that birds evolved from theropods because of other evidence that is not presented in this thread.
Unfortunately, I think this is the wrong way to look at things. If you want to provide evidence for the possibility of relationship, you have to look at the biggest differences possible between the two, not the smallest. If these biggest differences can be had with step-by-step fashion, then it is much stronger evidence of relationship than if you do the same exercise but on the aspects that are similar as CS did.
I replied to something simliar in a previous message (also Message 16):
quote:
This is why it is more important to look at the differences, and see if an evolutionary mechanism can account going from one state to the other.
I guess you're right, in that it would be better to try to prove that evolution couldn't do it, and then when we fail to prove that, we've shown that it could have, but that isn't the experience I'm trying to share here.
We here from creationists and IDists that microevolution cannot lead to macroevolution, and they request examples of where it could. This is my attempt at providing that example, in addition to sharing an experience that I enjoyed and found helpful in understanding all this.
Seriously, go look an emu in the eyes and taunt it to hiss at you and then come back and tell me that it didn't seem a lot like a lizard. Oh, and don't forget to look at its dragony feet while you're there. It was an awesome experience.
I don't think we're ever going to prove anything to creationists/IDist.
They've said this thing (one kind becomming another) has never been shown to be able to happen.
I think what has been presented here does show that it could have happened.
I'm not trying to offer proof that it has, I'm showing that it could have.

This message is a reply to:
 Message 36 by slevesque, posted 01-29-2010 1:09 AM slevesque has replied

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 Message 53 by slevesque, posted 01-29-2010 4:29 PM New Cat's Eye has replied

  
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 49 of 150 (544936)
01-29-2010 3:55 PM
Reply to: Message 40 by cavediver
01-29-2010 4:09 AM


That's all well and good, Slevesque, that you are unconvinced by the hypothetical inter-relatedness. But that does leave us with the question - just how many pairs of animals were on the Ark in your estimation?
I don't know, but the emu and the therapods don't come from the same 'pair'. Of that I am pretty sure.

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slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 50 of 150 (544937)
01-29-2010 4:01 PM
Reply to: Message 44 by Huntard
01-29-2010 5:22 AM


What about the ERV's? or the fact that human chromosome two is a fusion of two chimp chromosomes?
ERV's are a very deep subject on their own. If you are very interested in talking about them a new topic would be good. It would give me the opportunity to learn more about it since it's not a subject that I have a lot of knowledge in.
Neither do I know a lot about the chromosomal fusion thing.

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slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 51 of 150 (544938)
01-29-2010 4:07 PM
Reply to: Message 46 by caffeine
01-29-2010 6:19 AM


Re: Feathers as novel features
It is true that scales and feathers are very different structures, and this is why most people who study this don't believe that feathers evolved from scales.
There is evidence, however, of the type of structure feathers are believed to have evolved from, and Sinosauropteryx is one of the dinosaurs we find it in. The ginger structures being discussed aren't true feathers - they lack the barbs, barbules and hooklets of real feathers, which are only found in birds and maniraptoran dinosaurs so far (Sinosauropteryx is a compsognathid, a different type of theropod). These are much simpler, hollow filaments, which were probably the ancestors of true feathers.
Ok, but don't these 'ginger structures' come from a previous structure in therapods ? If this wasn't scales, what was it ?

This message is a reply to:
 Message 46 by caffeine, posted 01-29-2010 6:19 AM caffeine has replied

Replies to this message:
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slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 52 of 150 (544939)
01-29-2010 4:09 PM
Reply to: Message 47 by menes777
01-29-2010 11:35 AM


Re: You are right Slevesque
Before I go any further, you are arguing for Creation right?
Yes, i'm a YEC.

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slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 53 of 150 (544940)
01-29-2010 4:29 PM
Reply to: Message 48 by New Cat's Eye
01-29-2010 12:20 PM


Science works by induction, not deduction. IF: Because only black ravens have been observed, the conclusion is that all ravens are black, and this conclusion is tentatively accpeted until a non-black raven is found. But just because only black ravens have been observed doesn't mean that there isn't a white one that we haven't observed. Its logically fallacious, yet it works.
Ok Yeah I get your point. After writing that down yesterday I was thinking about it and asking myself how such a relationship could be proven, and I could only see that in fact it probably couldn't even with an enormous amount of data. It was all then about how much data is enough data to accept it as true. Which is in fact this notion of tentatively accepting.
It's maybe because I'm in Mathematics (and physics) that I'm not comfortable when something isn't proven. I guess requiring everything to be proven is a luxury that isn't available in other domains.
Last time you said that, I replied with this (from Message 16):
I was trying to make a resume of everything I had said in the thread up to date. Not necessarily for you of course, but for newcomes who had maybe misunderstood me.
Close enough. In all honesty though, I know that birds evolved from theropods because of other evidence that is not presented in this thread.
I don't doubt that, although it wasn't apparent in the OP.
From message 16:
I guess you're right, in that it would be better to try to prove that evolution couldn't do it, and then when we fail to prove that, we've shown that it could have, but that isn't the experience I'm trying to share here.
I am not suggesting a different exercise. I'm suggesting the same exercise you did in the OP, but instead of doing it on the feet, maybe doing it on the feathers.
I don't think we're ever going to prove anything to creationists/IDist.
They've said this thing (one kind becomming another) has never been shown to be able to happen.
I think what has been presented here does show that it could have happened.
I'm not trying to offer proof that it has, I'm showing that it could have.
But as long as you take very similar structures like the feet, your case of showing that it could have will remain very weak. Because the areas where it needs to be shown that the transition can be done must be in the hard ones unfortunately.

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 Message 48 by New Cat's Eye, posted 01-29-2010 12:20 PM New Cat's Eye has replied

Replies to this message:
 Message 54 by New Cat's Eye, posted 01-29-2010 4:52 PM slevesque has replied
 Message 55 by DC85, posted 01-31-2010 5:03 PM slevesque has replied

  
New Cat's Eye
Inactive Member


Message 54 of 150 (544941)
01-29-2010 4:52 PM
Reply to: Message 53 by slevesque
01-29-2010 4:29 PM


But as long as you take very similar structures like the feet, your case of showing that it could have will remain very weak.
Think about it though....
How do you tell one kind from another if not by how they look? Things that look different are different kinds and things that look the same are the same kind.
Having the same feet is just another reason them being the same kind.
That there's so much similarity when we look close suggests that they're not the different kinds that they look like as a whole.
Because the areas where it needs to be shown that the transition can be done must be in the hard ones unfortunately.
Like the feathers?
There's pleny of websites that show the evolution of feathers:
http://www.sussexdinosaurmuseum.co.uk/feathers.htm
Feather Evolution - from Dinosaur to Bird Evolution
Feather - Wikipedia
Some theropods already had feathers before the birds.
I don't see that one as being particularly difficult.
Is there another one that you think would be better?

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 Message 53 by slevesque, posted 01-29-2010 4:29 PM slevesque has replied

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DC85
Member (Idle past 379 days)
Posts: 876
From: Richmond, Virginia USA
Joined: 05-06-2003


Message 55 of 150 (545075)
01-31-2010 5:03 PM
Reply to: Message 53 by slevesque
01-29-2010 4:29 PM


quote:
Because the areas where it needs to be shown that the transition can be done must be in the hard ones unfortunately. .
what would you consider a transition? and what needs to be observed to show the relation of two species? As far as Humans and chimps we not only have physical similarities but DNA and embryonic.
To be honest it confuses me when people say that isn't evidence. To add to that evidence we also have fossilized Hominid fossils.
What else is needed?
I will admit our theropod to bird evolution case is not nearly as strong as our human evolution case however it is a strong case based on similarities between multiple species. Yet even human evolution is not seen to be a strong case to you. Most creationists admit "microevolution" happens however when someone says generations upon generations of "microevolution" produce a new "kind" for some odd reason that isn't acceptable when it's the exact same mechanism....
Edited by DC85, : No reason given.

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slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 56 of 150 (545133)
02-01-2010 3:32 PM
Reply to: Message 54 by New Cat's Eye
01-29-2010 4:52 PM


Think about it though....
How do you tell one kind from another if not by how they look? Things that look different are different kinds and things that look the same are the same kind.
Having the same feet is just another reason them being the same kind.
That there's so much similarity when we look close suggests that they're not the different kinds that they look like as a whole.
Hey, I know it seems to you like the similarities are so numerous that it should convince just about any reasonable person of the possibility that this is the case.
Unfortunately, I'm not the only one that isn't convinced. Alan Feduccia is maybe the leading expert on the subject, and he does not think birds came from therapods. If I remember correctly, he says that there is more reason to believe they came from a arboreal-type dinosaur (tree-dwon hypothesis) and leaves the door open for birds not to have evolved from dinosaurs at all.
A recent research by an Oregon state university team also showed evidence of why they do not agree that birds descended from therapods. The press release of this research has some interesting things to say, so I'll put them here:
OSU research on avian biology and physiology was among the first in the nation to begin calling into question the dinosaur-bird link since the 1990s. Other findings have been made since then, at OSU and other institutions, which also raise doubts. But old theories die hard, Ruben said, especially when it comes to some of the most distinctive and romanticized animal species in world history.
Frankly, there’s a lot of museum politics involved in this, a lot of careers committed to a particular point of view even if new scientific evidence raises questions, Ruben said. In some museum displays, he said, the birds-descended-from-dinosaurs evolutionary theory has been portrayed as a largely accepted fact, with an asterisk pointing out in small type that some scientists disagree.
Our work at OSU used to be pretty much the only asterisk they were talking about, Ruben said. But now there are more asterisks all the time. That’s part of the process of science.
This discovery probably means that birds evolved on a parallel path alongside dinosaurs, starting that process before most dinosaur species even existed, Ruben noted.
That’s quite possible and is routinely found in evolution. It just seems pretty clear now that birds were evolving all along on their own and did not descend directly from the theropod dinosaurs, which lived many millions of years later, said Quick.
Discovery raises new doubts about dinosaur-bi | EurekAlert!
For their part, they leave open the idea that crocodilians, dinosaurs and birds had a common ancestor in the distant past.
There's pleny of websites that show the evolution of feathers:
Loading...
http://www.dinosaur-world.com/...saurs/feather-evolution.htm
Feather - Wikipedia
And this is all a lot of suppositions, the biggest one of all being that feathers evolved endothermy. Of course, Feduccia has a lot to say bout this aspect. Considering that feathers are the perfect aerodynamical structure, they’re strong, light, asymmetric, produce slotting wings, and are like Velcro in that they can return back to their original position. Plus they’re waterproof. He calls them the most complex structure ever to grow out of vertebrate skin. They seem custom made for flight, yet are claimed to have evolved from endothermy! Not only that, but feathers are energetically and embryologically costly to produce. They are very good for flying and not exceedingly good at anything else. (far from being the best endorthemical structure) Feduccia simply proposes that feathers look designed for flight because that is what they evolved for, not endothermy (or else they would appear fit optimized for endothermy)
Some theropods already had feathers before the birds.
Strange since birds are found before therapods in the fossil record. And so the evolution of feathers still remains a mystery.
Is there another one that you think would be better?
If you think your response for the feathers is good enough (which I must say seemed like a rather superficial research on your part), then I guess you could try with the avian lung system, complete with the involvement of the femur.
Edited by slevesque, : No reason given.

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slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 57 of 150 (545134)
02-01-2010 3:43 PM
Reply to: Message 55 by DC85
01-31-2010 5:03 PM


what would you consider a transition? and what needs to be observed to show the relation of two species? As far as Humans and chimps we not only have physical similarities but DNA and embryonic.
To be honest it confuses me when people say that isn't evidence. To add to that evidence we also have fossilized Hominid fossils.
What else is needed?
We briefly overlooked humanid evolution with huntard a bit earlier I believe. Since it wasn't in the subject I referred the book 'bones of contention'.
You ask what ese is needed. For similarities to be conclusive proof of common descent, you need to be able to prove that all other options aren't possible. One of those options is convergent evolution. You need to find a physical criteria that can be observed that show convergent evolution took place and not common descent. Dr. Adequate said earlier that convergent evolution causes only superficial ressemblance but no in depth similarities. I have a hard time accepting this idea as valid, so maybe if it could be explained in detail and how a criteria for convergent evolution can be clearly stated out of this.

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Replies to this message:
 Message 58 by menes777, posted 02-02-2010 11:56 AM slevesque has replied
 Message 59 by Taq, posted 02-02-2010 12:27 PM slevesque has replied
 Message 65 by Peepul, posted 02-03-2010 8:35 AM slevesque has replied

  
menes777
Member (Idle past 4318 days)
Posts: 36
From: Wichita, KS, USA
Joined: 01-25-2010


Message 58 of 150 (545224)
02-02-2010 11:56 AM
Reply to: Message 57 by slevesque
02-01-2010 3:43 PM


quote:
You ask what else is needed. For similarities to be conclusive proof of common descent, you need to be able to prove that all other options aren't possible.
I think one of the faults with creationism is that it's mainly based on the arguments attempting to disprove rather than prove. That if you can disprove evolution than you prove creationism right. Evolution is the opposite and only attempts to prove what it can support not what it can disprove. Thus the objective here isn't to disprove everything except common descent but attempt to prove it with the evidence that we have.
quote:
One of those options is convergent evolution.
This sounds more like another one of those "What if" scenarios I keep hearing about. What if humans evolved at the same time as chimpanzees and evolved with the exact same features?
quote:
You need to find a physical criteria that can be observed that show convergent evolution took place and not common descent.
Didn't you mean this sentence to have common descent and convergent evolution to be switched? Also do you have any way to explain how convergent evolution applies to human and chimp evolution?
quote:
Dr. Adequate said earlier that convergent evolution causes only superficial resemblance but no in depth similarities. I have a hard time accepting this idea as valid, so maybe if it could be explained in detail and how a criteria for convergent evolution can be clearly stated out of this.
Look at bird wings and look at bat wings. Both are wings and when viewed from afar they appear to be the same. Yet when examined closely the difference is obvious. Bird wings have feathers, bat wings do not. The bone structure of bat wings is different from bird wings. Therefore the similarities are only superficial.

This message is a reply to:
 Message 57 by slevesque, posted 02-01-2010 3:43 PM slevesque has replied

Replies to this message:
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Taq
Member
Posts: 9970
Joined: 03-06-2009
Member Rating: 5.6


Message 59 of 150 (545227)
02-02-2010 12:27 PM
Reply to: Message 57 by slevesque
02-01-2010 3:43 PM


For similarities to be conclusive proof of common descent, you need to be able to prove that all other options aren't possible.
If we applied this same criteria to all ideas then nothing could be known for sure. I can't even prove that I woke up this morning since it is possible that the universe was poofed into being just 5 minutes ago, complete with a false history and false memories.
Proof through disproof is a very poor way of seeking knowledge, IMHO. Proof itself, in the absolute sense, is unattainable. What we can do is see if a model makes testable predictions, and then test those predictions. That is what science does. It tests models.
As to common descent v. convergence the test is in the DNA. Convergence can not produce a nested hierarchy at the DNA level for a whole genome. It is possible to do so for a couple mutations here and there, but practically impossible at the genome level. There is simply no mechanism by which a mutation in mice will cause the same mutation to occur in humans, as one example.
Dr. Adequate said earlier that convergent evolution causes only superficial ressemblance but no in depth similarities. I have a hard time accepting this idea as valid, so maybe if it could be explained in detail and how a criteria for convergent evolution can be clearly stated out of this.
A good example is the bill of the platypus and the bill of the duck. These two features do resemble each other superficially, but what happens when we look at the details? It turns out that the two bills are quite different:
Duck:
1. lower jaw is made up of three bones as in other birds.
2. bill is covered by horn.
3. Nares are near the base of the bill.
4. upper jaw is made of solid bone.
Platypus:
1. lower jaw is made up of a single dentary bone as in other mammals.
2. bill is covered in skin.
3. Nares are near the end of the bill.
4. Upper jaw has a split palate.
Here is a picture of the two skeletal structures:
Duck:
Platypus:
If all you saw was the skeletal structure you would never suggest that they were anything alike, or at least I wouldn't.

This message is a reply to:
 Message 57 by slevesque, posted 02-01-2010 3:43 PM slevesque has replied

Replies to this message:
 Message 61 by slevesque, posted 02-02-2010 3:46 PM Taq has replied

  
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 60 of 150 (545245)
02-02-2010 3:33 PM
Reply to: Message 58 by menes777
02-02-2010 11:56 AM


I think one of the faults with creationism is that it's mainly based on the arguments attempting to disprove rather than prove. That if you can disprove evolution than you prove creationism right. Evolution is the opposite and only attempts to prove what it can support not what it can disprove. Thus the objective here isn't to disprove everything except common descent but attempt to prove it with the evidence that we have.
This is a bit off-topic, but I'll give a brief answer anyways. Creationist don't solely have evidence against evolution, they also have evidence for creation.
Now, in the case of evidence against evolution, sure creationists uses them a lot. And they are not necessarily proof of a 6000 year old creation of the world obviously. Rather, arguments against the evolution of species simply becomes evidence for the statistity of species (in which of course the biblical creation fits well obviously)
Now, I think you misunderstood my statement there. I wasn't saying you have to disprove all other options in order to prove common descent. I was saying that if you want similarities alone to be sufficient proof for common descent, then you have to disprove all other options. Of course, anyone with some knowledge of philosophy of science will realise that this is an impossible feat to accomplish, and therefore similarities are unsufficient by themselves to prove common descent.
Didn't you mean this sentence to have common descent and convergent evolution to be switched? Also do you have any way to explain how convergent evolution applies to human and chimp evolution?
I meant this sentence as: In a given situation, is thee a way to show that common descent took plce and not convergent evolution?
Look at bird wings and look at bat wings. Both are wings and when viewed from afar they appear to be the same. Yet when examined closely the difference is obvious. Bird wings have feathers, bat wings do not. The bone structure of bat wings is different from bird wings. Therefore the similarities are only superficial.
Not the best example of convergent evolution, I prefer Taq's example with duck and platypus bills. Although everything I will say on that issue would probably apply to your example.

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