tag:blogger.com,1999:blog-3049195237412585561.post6761608346852496076..comments2023-11-07T12:07:59.585-08:00Comments on Pterosaurs to Birds: Something to NoteUnknownnoreply@blogger.comBlogger332125tag:blogger.com,1999:blog-3049195237412585561.post-80075515002068763292011-10-19T16:44:30.183-07:002011-10-19T16:44:30.183-07:00I have been patient with Harry Seeley but enough i...I have been patient with Harry Seeley but enough is enough. <br /><br />My mistake was even getting into a discussion about cladistics. As I have said those arguments go nowhere. <br /><br />If anyone wants to discuss the pterosaur to bird or dino to bird ideas, please do so in <i>basic evolution terms </i>such as ancestor, descendant, speciation (allopatric, sympatric etc).Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-38301077546288181432011-10-19T16:24:51.327-07:002011-10-19T16:24:51.327-07:00Harry Seeley your run-around is tiresome. You have...Harry Seeley your run-around is tiresome. You have jumbled a lot of words together and still not explained what happened at the node. <br /><b>If anything, you are speculating about what happens on the lines between nodes. </b><br /><br />I am familiar with the following kind of spin: <br />"Surely you do not propose that birds became flightless in a SINGLE speciation event? Did Hesperornis 'develop' from flying ancestors in a single speciation event? Did Utahraptor 'develop' from a small, flying dromeosaurid in a single speciation event."<br /><br />This is the last of your comments that I will post. I am tired of wasting my time on your spin and run-around.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-69335795658403640842011-10-19T15:07:47.430-07:002011-10-19T15:07:47.430-07:00How do you know the "flying group" did n...How do you know the "flying group" did not change? In fact, what PREVENTS it from changing?<br /><br />I made very specific points. You ignored them as usual. Here they are again:<br /><br />Flightlessness does not suddenly occur: Like I said, the path for such a significant phenotypic change is lined with many different speciation events over a considerable amount of time. Surely you do not propose that birds became flightless in a SINGLE speciation event? Did Hesperornis 'develop' from flying ancestors in a single speciation event? Did Utahraptor 'develop' from a small, flying dromeosaurid in a single speciation event?<br /><br />Now, if you want to have a node between a flying and a flightless group, the transition happens AT THE NODE. Not AFTER that.<br /><br />Are you saying that's a single speciation event?<br /><br />And during that event (or series of events, as I said) what STOPS one of the two groups from changing? <br /><br />The answer is, NOTHING. BOTH groups change with every speciation. Continuous changes accumulate and further separate the two groups. In the flying bird example that you want us to "stick with", one group gradually turns to flightlessness, while the other maintains flight, but that does not mean the other group is frozen in time it just changes in a different way.<br /><br />It's apretty simple concept. Read the text of the link you posted.Harry Seeleyhttp://en.wikipedia.org/wiki/Harry_Seeleynoreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-16316122213848640942011-10-19T14:55:06.165-07:002011-10-19T14:55:06.165-07:00"What makes you think that one did not change..."What makes you think that one did not change? And how can you tell which one (if any) didn't change, in my horse example? There are no flying and flightless taxons there. In fact, how can you tell which 'didn't change' in the FLYING BIRD example? Not all "flying birds" are identical, nor are they a single taxon. What's to say the flying group did not ALSO have a substantial amount of change?"<br /><br /><br />Let's stick with the flying and flightless example. <br />And let's not talk about what may or may not happen to the flying birds after the node. <br />What happened at the node? <br />All that happened was that the subgroup split and settled on the land and became a different taxa. <br /><br />This is getting tiresome Harry Seeley. <br /><br />Can anyone answer the question I asked without all the run-around.<br />What happened at the node?Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-82802669201975676282011-10-19T14:35:51.072-07:002011-10-19T14:35:51.072-07:00What makes you think that one did not change? And ...What makes you think that one did not change? And how can you tell which one (if any) didn't change, in my horse example? There are no flying and flightless taxons there. In fact, how can you tell which 'didn't change' in the FLYING BIRD example? Not all "flying birds" are identical, nor are they a single taxon. What's to say the flying group did not ALSO have a substantial amount of change?<br />And flightlessness does not suddenly occur: Like I said, the path for such a significant phenotypic change is lined with many different speciation events over a considerable amount of time. Surely you do not propose that birds became flightless in a SINGLE speciation event? Did Hesperornis 'develop' from flying ancestors in a single speciation event? Did Utahraptor 'develop' from a small, flying dromeosaurid in a single speciation event?<br /><br />In my basic example, as I said, I simplified the process as much as possible to show you that BOTH new groups, according to cladistics, change with every speciation event. Different, small genetic variations accumulate in both (variations that may or may not have a phenotypic effect), eventually making interbreeding impossible. No group stays 'frozen in time', so to speak.<br /><br />But here's some expanding on my example. Suppose that, when we see the two populations again, one has grown significantly larger in size, while the other remains the same size as the ancestral one, more or less. Now, according to you (and others, especially in the past) we might consider the 'unchanged' species as the "original" one, and the larger one as the "changed" one.<br /><br />But suppose we have kept some DNA from the "original" population from many years ago, we compare it to the two species, and we find that it's the 'similar' one that's more genetically different! Sounds implausible? Actually, it's more likely than you think. Look at the diversity in size and shape in dogs today; it doesn't stop them from being the same species. On the other hand, animals like the Okapi, as well as several kinds of cattle, have undergone cases of chromosomal fusion, which reduces their ability to interbreed, although it has hardly any phenotypic effect.<br /><br />In other words, "change" is very shaky and subjective criteria for claiming one species is the "original" one, and one is not. BOTH groups accumulate different genetic changes as they become reproductively isolated, and THAT is what the link you posted says (it would be wise to read the text and not just look at the colors of the charts). And besides, significant phenotypic change like loss of flight does not happen in a single speciation event.<br /><br />"Are you trying to waste my time again Harry Seeley?<br /><br />Can anyone actually tell us what happens at a node"?<br /><br /><br />I just did, in detail and with examples. It's up to you to refute my points, or simply (and quite obviously) admit you cannot by blocking my comments again. Your call.Harry Seeleyhttp://en.wikipedia.org/wiki/Harry_Seeleynoreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-18804722746927560402011-10-19T13:42:34.751-07:002011-10-19T13:42:34.751-07:00The original one is the one that did not change.
...The original one is the one that did not change. <br />At that point there is the original and the one that changed. <br />Take a look at the speciation diagrams and the different forms of speciation. <br />http://en.wikipedia.org/wiki/Speciation<br /><br />For example let us start with a group of flying birds. A subgroup splits off and settles on the land and loses its flying characteristics becoming flightless - becoming a new taxa. At that point we have the original flying taxa unchanged and the new flightless taxa. <br /><br />Are you trying to waste my time again Harry Seeley? <br /><br />Can anyone actually tell us what happens at a node?Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-40753339058796234082011-10-19T12:51:28.796-07:002011-10-19T12:51:28.796-07:00Actually, it was probably a series of different sp...Actually, it was probably a series of different speciation events, in a non-insignificant amount of time. But hypothetically, let's simplify the process. Let's say that a hypothetical Horse taxon consists of a single population of a single species. And that Horse taxon undergoes a single speciation event. <br /><br />The horse population lives on either side of a valley. Animals freely move across the valley, and the population remains unified. Then the valley begins to deepen, or a river floods, and the population is separated into two different groups. We leave the hories be in their isolation of X amount of time, and, when we find them again, we see they cannot interbreed.<br /><br />Clearly the one 'taxon' has now become two.<br /><br />But which is the "original" taxon?<br /><br />The answer, of course, is 'neither'.Harry Seeleyhttp://en.wikipedia.org/wiki/Harry_Seeleynoreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-88150886045083524202011-10-19T12:28:19.263-07:002011-10-19T12:28:19.263-07:00"The original taxon has been REPLACED by the ..."The original taxon has been REPLACED by the two new ones;" <br /><br />What was the process? Was it one of:<br />Allopatric speciation? Parapatric speciation? Perapatric speciation? Sympatric speciation?<br /><br />Or some other process?Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-50364013508159428992011-10-19T11:55:07.948-07:002011-10-19T11:55:07.948-07:00"If nothing dies off, then the original taxon..."If nothing dies off, then the original taxon continues". <br /><br />No. The 'original' taxon CHANGES into two different taxa. It doesn't "die off"; The descendants of the initial population form two distinct populations. <br /><br />"Is that original taxon one of the two taxa that exists after the node? If so, why do you say there are "two different taxa"? <br /><br />Neither of the two new taxa are "original" in cladistics. The original taxon has been REPLACED by the two new ones; but it hasn't "died off". Dying off for a taxon means leaving no descendants, when the very descendants of the original taxon are the two new taxa.<br /><br />You can imagine it a bit like an amoeba splitting in two; the original organism ceases to exist, and is replaced by two new ones, but it doesn't "die off".<br /><br />It's only a very crude analogy, but it might help you understand the basic concept. I can elaborate with other more accurate examples, if you still don't get it.Harry Seeleyhttp://en.wikipedia.org/wiki/Harry_Seeleynoreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-55293393838158324192011-10-19T10:41:47.164-07:002011-10-19T10:41:47.164-07:00If anyone else would like to join in on this discu...If anyone else would like to join in on this discussion about what happens at the node please do.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-21174276390410153302011-10-19T10:19:43.468-07:002011-10-19T10:19:43.468-07:00If nothing dies off, then the original taxon conti...If nothing dies off, then the original taxon continues. <br />Is that original taxon one of the two taxa that exists after the node? If so, why do you say there are "two <i>different </i>taxa"? <br /><br />For example, let us say we begin with Taxon A. And then there is a node. <br />What exists after the node?Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-8269797128455652462011-10-19T09:38:37.392-07:002011-10-19T09:38:37.392-07:00Nothing "dies off".
An original taxon ...Nothing "dies off". <br /><br />An original taxon becomes two different taxa. It's a CHANGE.<br /><br />Stop trying to sneak terms into the concept. It's not that hard to grasp.Harry Seeleyhttp://en.wikipedia.org/wiki/Harry_Seeleynoreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-45561867643701768712011-10-19T07:28:39.368-07:002011-10-19T07:28:39.368-07:00Harry Seeley posted:
"AT THE NODE, A SPLITTI...Harry Seeley posted:<br /><br />"AT THE NODE, A SPLITTING EVENT OCCURS. AN ANCESTRAL TAXON BECOMES TWO DIFFERENT TAXONS."<br /><br />So at the node the ancestor dies off and is replaced by "two different taxons". <br />Both taxons [taxa] different from the ancestor and different from each other.<br /><br /><b>Does anyone agree with this?</b><br /><br /><br />This is consistent with the passage from<br />http://www.ucmp.berkeley.edu/clad/clad3.html<br />"The node therefore represents the end of the ancestral taxon, and the stems, the species that split from the ancestor."Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-888568997642782462011-10-19T06:47:34.240-07:002011-10-19T06:47:34.240-07:00People here need not feel bad that they cannot tel...People here need not feel bad that they cannot tell us what happens at a node. <br />Nobody can. <br />The whole cladistic concept is misguided. <br /><br />But there is really no point in arguing this since nobody can even tell us what happens at a node. <br /><br />So if people wish to contribute to the idea of this blog just use basic evolution ideas such as ancestor, descendant, speciation (eg. allopatric speciation, parapatric speciation etc).Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-24890137961433438142011-10-19T04:45:22.867-07:002011-10-19T04:45:22.867-07:00A Nonny Mouse cannot tell us what happens at a nod...A Nonny Mouse cannot tell us what happens at a node. <br />Anyone else?Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-47227957473048648872011-10-19T03:53:18.220-07:002011-10-19T03:53:18.220-07:00Actually it looks like no-one can be bothered answ...Actually it looks like no-one can be bothered answering you in words of one syllable. Nodes are cladogenic events. Perhaps you should contact the authors of the article that you are having difficulty with and ask them to explain what they mean in "simple ancestor-descendant terms"?<br /><br />There is a "Standard Theory", you've linked to the cladograms that describe it often enough. And you've been referred to the evidence that supports neornithines as a monophyletic group. You seem to be ignoring it? Read the papers you have been referred to.A Nonny Mousenoreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-43361089557214034812011-10-18T18:10:51.507-07:002011-10-18T18:10:51.507-07:00It looks like nobody can answer that basic questio...It looks like nobody can answer that basic question.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-22390005945268883072011-10-18T10:17:01.102-07:002011-10-18T10:17:01.102-07:00"At each node a splitting event occurs. The n..."At each node a splitting event occurs. <b>The node therefore represents the end of the ancestral taxon,</b> and the stems, the species that split from the ancestor." <br /><br /><br />What are the possibilities of what occurs at a node? <br />Is it something other than one of the speciation possibilities of allopatric speciation, peripatric speciation, parapatric speciation, or sympatric speciation?<br /><br />In each of these forms of speciation, <b>the original group continues to exist </b>and a new (second) species originates. <br /><br />What happens at a node? <br />There seems to be two quite different stories about what happens at a node.<br /><br /><b>Can anyone answer this?</b>Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-18476771126899089362011-10-18T10:15:54.551-07:002011-10-18T10:15:54.551-07:00Harry Seeley - I have said I am not wasting time o...Harry Seeley - I have said I am not wasting time on your misconceptions. <br />Also I ave said that people can argue any point till the cows come home.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-20686293751605127532011-10-18T10:01:19.823-07:002011-10-18T10:01:19.823-07:00Dr. Pterosaur, here is what is happening.
You post...Dr. Pterosaur, here is what is happening.<br />You post some misconception you have and then I have to spend a lot of time trying to get you to understand where you are going wrong. And that just leads to you ignoring my response, or blocking my comment.<br />This is indeed time consuming.<br />Indeed I do not have the time to educate you.<br /><br />I will however give it another shot, in case it sinks in:<br /><br />In your previous posts (your words are there for all to see), you claimed that the cladograms show that Neornithes are NOT "close" to Dromeosaurids.<br /><br />As I explained, that is obviously false. The cladograms show there is NO animal other than dromeosaurids and troodontids closer to modern birds, that isn't ALSO a bird.<br /><br />Now, It is POSSIBLE that Dromeosaurids will turn out to be paraphyletic to birds. And, in that case, Aves will be included WITHIN a monophyletic Dromeosaurid clade.<br /><br />Or it may not, turn out that way- that is what "COULD BE" means after all.<br /><br />And nothing in that contradicts or invalidates the 'Dino-to-Bird' theory.<br /><br />As for the "two possibilities": The SECOND one is reflecting the "Birds Came First" hypothesis, a hypothesis that is neither mainstream nor adequately supported, simply pushed by a group of people with an agenda. And the article you link to is one such example.<br /><br />And these are the FACTS. Just so we have a firm grasp what the term 'fact' means.Harry Seeleyhttp://en.wikipedia.org/wiki/Harry_Seeleynoreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-36272635324390177992011-10-18T09:09:35.772-07:002011-10-18T09:09:35.772-07:00I know that nobody can tell us what happens at a n...I know that nobody can tell us what happens at a node. It is the Achilles Heel of cladistics. <br />Nobody knows what happens there. <br /><br />If someone thinks they know, please tell us.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-17134357977794687292011-10-18T08:20:08.082-07:002011-10-18T08:20:08.082-07:00"At each node a splitting event occurs. The n..."At each node a splitting event occurs. <b>The node therefore represents the end of the ancestral taxon, and the stems, the species that split from the ancestor." </b><br /><br /><br />What are the possibilities of what occurs at a node? <br />Is it something other than one of the speciation possibilities of allopatric speciation, peripatric speciation, parapatric speciation, or sympatric speciation?<br /><br />In each of these forms of speciation, the original group continues to exist and a new (second) species originates. <br /><br /><b>What happens at a node? </b><br />There seems to be two quite different stories about what happens at a node.<br /><br />Can anyone answer this?Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-16209162200266475672011-10-18T08:17:59.465-07:002011-10-18T08:17:59.465-07:00What I am pointing out is that there is no "s...What I am pointing out is that there is no "standard theory". <br />I have presented a consistent, credible lineage leading to modern birds. <br />There is no alternative that anyone has proposed. <br />There is no point in arguing this point. It is simply a fact. <br />If someone would like to present what the dino to bird lineage is, please do so, <br />Otherwise there is no point in arguing this.Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-66043030272769888532011-10-18T08:01:30.303-07:002011-10-18T08:01:30.303-07:00Harry Seeley, here is what is happening.
You post...Harry Seeley, here is what is happening. <br />You post some misconception you have and then I have to spend a lot of time trying to get you to understand where you are going wrong. And that just leads to an endless argument. <br />This is time consuming.<br />I do not have the time to educate you. <br /><br />The bottom line is that the commonly accepted cladogram - for example the one listed in the wiki entry for coelurosauria - does NOT show birds evolving from Dromaeosaurids. <br /><b>And yet that is what people are leaning toward presently. </b><br /><br />The two cladograms from the reference I gave show the two conflicting hypotheses. <br /><br />The real bottom line is that Dromaeosaurids are ANCESTRAL* (paraphyletic) to modern birds. <br />That of course is a fundamental idea of what I am presenting. <br /><br /><br />* http://en.wikipedia.org/wiki/Dromaeosauridae#Flying_and_gliding<br />"As late as 2001, Mark Norell and colleagues analyzed a large survey of coelurosaur [maniraptor] fossils and produced the tentative result that dromaeosaurids were most closely related to birds, with troodontids as a more distant outgroup. <b>They even suggested that Dromaeosauridae could be paraphyletic [ancestral] relative to Avialae."</b>Dr. Pterosaurhttps://www.blogger.com/profile/13137867768653523183noreply@blogger.comtag:blogger.com,1999:blog-3049195237412585561.post-61460941373658639022011-10-18T07:33:55.337-07:002011-10-18T07:33:55.337-07:00"No, the second cladogram is not a Birds Came..."No, the second cladogram is not a Birds Came First hypothesis.<br />It is a cladogram based on the idea that Dromaeosaurids are part of Aves".<br /><br />...Which is a crucial part of the BCF hypothesis. The hypothesis that birds evolved from early archosaurs, and maniraptor dinosaurs were simply more derived forms of birds. Exactly what the whole paper presents as "equally probable".<br /><br />Did you bother to read the paper you linked to?<br /><br />Also, from your silence on the other point about the closeness of dromeosaurids and neornithes, I take it that you realized your mistake (It's OK, I don't expect you to admit it).Harry Seeleyhttp://en.wikipedia.org/wiki/Harry_Seeleynoreply@blogger.com