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Author Topic:   Theropods and Birds showing a change in kinds
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 3 of 150 (542015)
01-07-2010 9:36 AM
Reply to: Message 1 by New Cat's Eye
01-06-2010 12:39 PM


Interesing, I have also always thought that this:
Astonishingly looked like this:
I hope you can see my point. Similarity, either in the phenotype or the genotype, does not prove relationship unfortunately. 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.
The example you talked about with scales and feathers would be one such difference (and a topic of it's own, or we can discuss it here), because maybe I don't have enough imagination, but I don't see a feather as an elongated and modified scale.

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


Message 6 of 150 (542031)
01-07-2010 10:25 AM
Reply to: Message 4 by Huntard
01-07-2010 9:44 AM


It was to show that if the classical example of chimp and human similarities does not convince me of relationship, neither will an emu and a theropod.
CS wants to prove relationship with similarity, but it just isn't enough. It's the classical case of affirming the consequent:
Related species would have similar features
Two species have similar features
therefore they are related
Which is fallacious. Besides, any knowledgeable evolutionists should know this, considering the sizeable amount of convergent evolution examples in my biology book ...

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 Message 7 by hooah212002, posted 01-07-2010 10:41 AM slevesque has replied
 Message 8 by Larni, posted 01-07-2010 10:46 AM slevesque has replied
 Message 9 by Dr Adequate, posted 01-07-2010 10:47 AM slevesque has replied
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slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 10 of 150 (542041)
01-07-2010 10:53 AM
Reply to: Message 7 by hooah212002
01-07-2010 10:41 AM


I would suggets you reread the OP, as CS has made it clear that he judges this line of reasoning to be sufficient to affirm relationship:
Creationists and IDists have asked for examples of one kind evolving into another and this is my attempt to share with them what I've found convincing of just that.
I'm trying to be very general here and am not implying that ostriches are direct decendents of velociraptors, but I think its obvious that birds did decend from theropods. And that its a great example of one kind becomming another.
(emphasis in original)
I found it convincing. Do you?
I'm not saying there are no other evidence as you have said.
What I'm saying is that CS has given only this evidence, and declared it to be sufficient to convince him of relationship.

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


Message 11 of 150 (542043)
01-07-2010 11:03 AM
Reply to: Message 8 by Larni
01-07-2010 10:46 AM


By the same logic you could argue that a tiger is not related to a sand cat.
I'm not sure if it is me misexpressing myself or maybe a lack of logical understanding on your part, but you cannot prove none-relationship by affirming the consequent.
Affirming the consequent is fallacious because it is not sufficient to prove the conclusion. It does not mean that the given conclusion is wrong, it just means that a correct logical path needs to be taken.
This only provides strong evidence that you will never be able to use evidence to alter the way you view the natural world.
Sorry for not being convinced by a fallacious argument ...
---------------
BTW, I know I use the word fallacious repeatedly, this is not an attack on CS. He is a very bright personand has shown it repeatedly, and logical ability is not in question. He just slipped in a hard-to-recognize fallacy and I'm trying to point it out. (Although with much more resistance then anticipated)
Edited by slevesque, : No reason given.
Edited by slevesque, : No reason given.

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


Message 12 of 150 (542047)
01-07-2010 11:12 AM
Reply to: Message 9 by Dr Adequate
01-07-2010 10:47 AM


But you could say that of all scientific knowledge whatsoever.
If all of scientific knowledge is based on affirming the consequent, then we're in deep shizzles.
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.
Convergent evolution is simply an example as to why affirming similar morphology is unsufficient to confirm relationship. I could have done a similar analysis as CS with tasmanian tigers and dogs in terms of morphological similarity, and of course no one would have concluded relationship between the two as CS has with Emu and theropods.
I also want to specify that affirming the consequent is necessary for the conclusion to be possible. This can be seen with it's counterpart, denying the consequent:
Two related species will have similar features
two species do not have similar features
therefore they are not related.
Which is a valid argument. Therefore, it shows that similarity is a required characteristic to conclude relationship, but it is not a sufficient one.

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


Message 13 of 150 (542048)
01-07-2010 11:15 AM


Note also that CS (fallaciously) shows a relationship between Emu's and theropods, only to conclude a relationship with all Birds. (As per his title)
Which is also fallacious.

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


Message 36 of 150 (544873)
01-29-2010 1:09 AM


Ok, I totally forgot I had started discussing in this thread so sorry about that. I'll just answer the couple of comments made about what I had said at the time to try and clarify things a bit.
menes77 said:
First someone compared a human to a chimpanzee. Yet they are related.
My first post with the two images wasn't very clear unfortunately. I was simply answering CS question about if I found his OP convincing of relationship between an emu and therapods.
The idea was simply that if phenotypical similarities between human and chimp didn't convince me nor prove anything, it was no different between birds and therapods. I clarified this shortly afterwards, but I guess you posted before reading the whole thread.
The reason I say it proves nothing is because it is an argument of the type ''affirming the consequent'' which is a logical fallacy. Similarities are a necessary condition for relationship, but they are not a sufficient condition to support it as a conclusion. Which brings me to the comment I made that made some waves:
Bluejay wrote:
slevesque writes:
If all of scientific knowledge is based on affirming the consequent, then we're in deep shizzles.
And yet, strangely, millions of scientists have been able to apply this method to real-world applications, with great success. If you call that "shizzles," then I suppose you're right.
CS wrote:
I find it hilarious when people claim science has problems over an internet discussion board. I mean, here we are, communicating instantly over great distances because of science.
The simple answer is that scientific knowledge is not based on affirming the consequent. That is why we are not currently in ''deep shizzles'' as I called it. When logical deduction is required to extrapolate a hypothesis from the data, non-fallacious forms of argumentation are rightfully used.
Now, I'm not saying that affirming the consequent isn't used in scientific investigation. And I would say it is frequently used in archaeology,history, etc. There is no problem in doing so as long as it is presented as showing a necessary condition for the hypothesis and not as an acceptable proof of the given hypothesis. 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.
_____________________________--------------------------------------------------
On a final note, I will add some meat to the discussion while I'm here. 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.
I hope I represented it as clearly and accurately as possible. 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.
And on a final note, to really put fuel in the discussion:
xongsmith said:
Hey guys! Just in from China:
"A team of scientists from China and the UK has now revealed that the bristles of this 125 million-year-old dinosaur were in fact ginger-coloured feathers."
BBC News - Dinosaur had ginger feathers
Check it out.
This gives more weight to a very well-supported theory that modern birds evolved from theropods, the group of small carnivorous dinosaurs to which Sinosauropteryx belonged."
"The findings also help to resolve a long-standing debate about the evolution and original function of feathers.
"We now know that feathers did not originate as flight structures," said Professor Benton. "This suggests that they evolved, initially, for insulation and perhaps for display. " "
Kinda timely, I'd say.
The following will be only my personal opinion: I am very skeptical of any fossils that come out of china, and I advice myself and any other willing to listen to always wait a couple of years before being sure of a fossil that come from there. The reason for my position on the issue is this:
Interview between Alan Feduccia and Discover:
quote:
Discover: What about all the other evidence for feathered dinosaurs?
Feduccia: When we see actual feathers preserved on specimens, we need to carefully determine if we are looking at secondarily flightless birds that have retained feathers and only superficially resemble dinosaurs, or if the specimens are in fact related to dinosaurs. That’s a difficult issue to deal with right now, given the existence of fake fossils.
Discover: So far, only one feathered dinosaur, Archaeoraptor, has been publicly acknowledged as a forgery. You think there are others?
Feduccia: Archaeoraptor is just the tip of the iceberg. There are scores of fake fossils out there, and they have cast a dark shadow over the whole field. When you go to these fossil shows, it’s difficult to tell which ones are faked and which ones are not. I have heard that there is a fake-fossil factory in northeastern China, in Liaoning Province, near the deposits where many of these recent alleged feathered dinosaurs were found.
Journals like Nature don’t require specimens to be authenticated, and the specimens immediately end up back in China, so nobody can examine them. They may be miraculous discoveries, they may be missing links as they are claimed, but there is no way to authenticate any of this stuff.
Discover: Why would anyone fake a fossil?
Feduccia: Money. The Chinese fossil trade has become a big business. These fossil forgeries have been sold on the black market for years now, for huge sums of money. Anyone who can produce a good fake stands to profit.

Replies to this message:
 Message 37 by Iblis, posted 01-29-2010 1:34 AM slevesque has replied
 Message 40 by cavediver, posted 01-29-2010 4:09 AM slevesque has replied
 Message 47 by menes777, posted 01-29-2010 11:35 AM slevesque has replied
 Message 48 by New Cat's Eye, posted 01-29-2010 12:20 PM slevesque has replied

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


Message 38 of 150 (544877)
01-29-2010 2:33 AM
Reply to: Message 37 by Iblis
01-29-2010 1:34 AM


Re: appearances
I intended the phrase you quote (and the entire paragraph where it is is my previous post) as being a resume of what CS was saying. The following phrases during this thread gave me that impression of what he was saying.
Example:
OP:
At first glance it should be obvious that these animals are two different kinds, but let's look closer.
message 16:
But its not just a cursory glance at their external morphologies. From that, it seems that the theropod and bird are different kinds. But when you look at them closely, or into them, and especially those feet!, you can see that a bunch of small changes, microevolutionary changes, to the theropod could easily get us to the point of being a bird.
It was an attempt by myself to show as accurately as possible what CS was saying in the most compact way possible.
-------
I'll add even more fuel to the discussion. I'll say that I do not believe it impossible that some dinosaur species had feathers. By this I mean real, complete feathers. I'm not saying this is the case; I never really researched a whole lot on this issue and the evidence for or against it. I'm saying that this is a possibility.
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.

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


Message 39 of 150 (544878)
01-29-2010 2:43 AM
Reply to: Message 17 by Larni
01-07-2010 4:23 PM


I'll just answer this small question very quickly so Larni won,t think I skipped over him:
What would make you think that a human and a chimp are not closely related (please don't forget endogenous retroviral markers)?
I'm afraid that in this situation, the burden of proof is on you. I personnally believe that the fossil evidence is inconclusive. ''Bones of contention'' by Lubenow is a good read on this issue to know the creationist perspective on many of the finer details and it isn't filled with a lot of biblical stuff, he pretty much sticks to the fossils at hand. He also keeps the dates assigned to the fossils and shows that even keeping the evolutionnary timeline there are many things that do not click.
On the genetic level I think the 98% similarity figure is a bit outdated and it probably hovers around 95% now. Even recently their was a study published about the study of the Y chromosome of chimps and humans and the differences were much, much bigger than anticipated.
Is this all still in the subject ?

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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 ?

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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:
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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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