Uncommon Descent Serving The Intelligent Design Community

Once upon a time, before DNA or RNA, there was TNA … if it ever existed in life forms

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From “Simpler Times: Did an Earlier Genetic Molecule Predate DNA and RNA?” (ScienceDaily, Jan. 9, 2012), we learn,

According to Chaput, one interesting contender for the role of early genetic carrier is a molecule known as TNA, whose arrival on the primordial scene may have predated its more familiar kin. A nucleic acid similar in form to both DNA and RNA, TNA differs in the sugar component of its structure, using threose rather than deoxyribose (as in DNA) or ribose (as in RNA) to compose its backbone.

In an article released online January 9 in the journal Nature Chemistry, Chaput and his group describe the Darwinian evolution of functional TNA molecules from a large pool of random sequences. This is the first case where such methods have been applied to molecules other than DNA and RNA, or very close structural analogues thereof. Chaput says “the most important finding to come from this work is that TNA can fold into complex shapes that can bind to a desired target with high affinity and specificity.” This feature suggests that in the future it may be possible to evolve TNA enzymes with functions required to sustain early life forms.

… research has now shown that a single strand of TNA can indeed bind with both DNA and RNA by Watson-Crick base pairing — a fact of critical importance if TNA truly existed as a transitional molecule capable of sharing information with more familiar nucleic acids that would eventually come to dominate life.

In “Before DNA, before RNA: Life in the hodge-podge world”(New Scientist, 08 January 2012), Michael Marshall notes

That doesn’t mean TNA was the original genetic material, though. Chaput thinks it probably wasn’t, if only because the chemistry of early Earth was so messy that TNA would not have arisen on its own. Rather, many different kinds of genetic material probably formed in a genetic hodge-podge. “The most likely scenario is that nature sampled lots of different things,” says Chaput.

Hmmm. What is “nature” that it should be doing any sampling?

Also,

… there are problems with the hodge-podge world hypothesis. For one thing, there is no trace of TNA or its cousins in modern organisms. For another, although TNA looks simpler than RNA, we can’t be sure it was easier to make some 4 billion years ago because no one has actually made it in the conditions that existed on Earth before life began, says John Sutherland of the MRC Laboratory of Molecular Biology in Cambridge, UK.

TNA has also not been found in life forms today, which is why the media release reads “ if TNA truly existed as a transitional molecule capable of sharing information with more familiar nucleic acids that would eventually come to dominate life.” You be the judge.

Comments
This is easing you gently through the features one might expect to find in a real tree of descent.
I would expect the offspring to have the same features as their parents. And that is what we see 99.9999999% of the time. The time when there is a difference is a loss of a part. So that doesn't help you.
You didn’t spot the conditional in that sentence. IF there was such an ancestor, that makes a prediction about the relationships we would expect to recover from modern genes.
It's heresay because you assume that the pattern observed can only be explained if they had a common ancestor.
If you have a sister and a kid who also had the gene, the nested hierarchy would be {dad’s copy{your copy{kid’s copy},sister’s copy}}
1- my kid may not have a copy from my dad 2- my kid could have a copy that better resembles my dad's copy than my copy does 3- My kid's copy could match my sister's copy. One more time- how are you constructing your gene tree? If you had no idea what the actual relationships were, how could you do it?Joe
January 24, 2012
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Chas: The set of any common ancestor and its descendants consists of and contains that ancestor and all its descendants. Joe: But you don’t have any idea what those are.
Totally not the point! This is easing you gently through the features one might expect to find in a real tree of descent. Then one uses these concepts to try and establish whether a dataset containing hypothetically commonly descended organisms actually fits that pattern. Of course you don't know what the organisms are! You want to see how their descendants relate, if at all, and you do so by trying to reconstruct a tree from the buds back.
Chas: Ergo, if there was a common ancestor to chimps and humans, we would expect to be able to recover such a hierarchy from examination of modern DNA, Joe: Heresay.
Heresy? Hearsay? You didn't spot the conditional in that sentence. IF there was such an ancestor, that makes a prediction about the relationships we would expect to recover from modern genes.
Look one can construct a nested hierarchy out of just about anything. Trees are nested hierarchies and my dad’s genes do not consist of nor contain my genes.
The set of your those genes you got from your dad and their homologues in him can be formed into a nested or a non-nested hierarchy according to whim. The simple hierarchy is: A gene in your dad and a descendant of that gene in you. Your dad's copy is hierarchically above you. The nested hierarchic set constructed from the ancestor and all its descendants is: {dad's copy{your copy}} The outer set is everything, the inner the lower levels. If you have a sister and a kid who also had the gene, the nested hierarchy would be {dad's copy{your copy{kid's copy},sister's copy}} The non-nested hierarchy is dad's copy your copy,sister's copy kid's copy Same data, different drawing.
So in what way are gene trees a nested hierarchy?
In the above way. In the sense that "an ancestor and all its descendants" can apply to a species, or a haplotype gene, or an asexual lineage, and each descendant node is itself "an ancestor and all its descendants", nested in the higher tree. Gets a little more complex with sex:
I take it you have never heard of recombination…
Recombination does indeed mess up trees. But it is not guaranteed to operate, and does so quite gently - average one crossover per chromosome, so a gene can stay intact for many generations. It may also function as a long-term haplotype due to inversions. And recombination makes no difference at homologous sites. They are homologous due to common descent, incidentally. Ultimately, the braided threads of sexual networks resolve into vegetative species branches, and at that level, recombination doesn't make a difference.Chas D
January 24, 2012
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The set of an ancestral species and all its descendants consists of and contains that species and all its descendants.
Right, that is the nested hierarchy based on "all life".
It sits at the top of a descendant hierarchy, the full set of which forms the outer set of all descendants.
Just as the general sits at the top of a military command, ie a non-nested hierarchy.
The set of any common ancestor and its descendants consists of and contains that ancestor and all its descendants.
But you don't have any idea what those are.
Ergo, if there was a common ancestor to chimps and humans, we would expect to be able to recover such a hierarchy from examination of modern DNA,
Heresay. Look one can construct a nested hierarchy out of just about anything. Trees are nested hierarchies and my dad's genes do not consist of nor contain my genes. So in what way are gene trees a nested hierarchy? I take it you have never heard of recombination...Joe
January 24, 2012
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nested hierarchies involve levels which consist of, and contain, lower levels.
The set of an ancestral species and all its descendants consists of and contains that species and all its descendants. The set of one of its descendant species and all its descendants sits right within the first set, since the first set includes the rest by definition. And so on. These successive hierarchies are nested. An ancestor is not a nested hierarchy. It sits at the top of a descendant hierarchy, the full set of which forms the outer set of all descendants. Sets-of-all-descendants at successively lower levels sit inside (are nested within) the superior set. If A gives rise to B and C, then B and C are nested hierarchically within {A,B,C}, thus {A,{B,C}}, not within A alone. You are simply confusing two kinds of hierarchy that can be used to represent the same branching pattern of descent.
The alleged common ancestor of chimps and humans does not consist of nor conatain chimps and humans.
The set of any common ancestor and its descendants consists of and contains that ancestor and all its descendants. Ergo, if there was a common ancestor to chimps and humans, we would expect to be able to recover such a hierarchy from examination of modern DNA, and reconstruct the non-nested hierarchy from a nested arrangement of descendants. If there wasn't, we would not. Nobody is suggesting that the common ancestor of chimps and humans would be a nested hierarchy. You need the descendants as well. Humans and chimps nest separately within the outer set of ancestor-and-humans-and-chimps.
As for molecular markers- there are only 4 possibilities for any one site and you have no idea how many times sites have changed and then changed back or converged.
As I have pointed out a few times now - I'm beginning to wonder if you're just messing with me! - molecular phylogeny is not solely dependent on point features. If there is a clear common sequence, then your bases having been through many intermediate mutations is not that relevant. It causes under-counting of changes, but does not fatally undermine the whole tree. Often, we can simply looking at a binary signal, Present and Absent. We cannot use degraded sites, but if we find a site we can identify, it must either be little-degraded or convergent. And widespread convergence at the nonfunctional molecular level is highly unlikely. The idea that the sequences could have both wibbled around phase space and ended up identical is the usual extravagant swerve from you, Joe. You would have to assert convergence of every sequence that supports common descent, and there is no support for such an improbable hypothesis. Why not just common descent? Simple, obvious, and involves no desperate mental gymnastics. All other options are ludicrous fantasy, on the data. Your designer is trying to trick us.
Trees are not necessarily a nested hierarchy. A family tree isn’t a nested hierarchy.
Gene trees are though, even in families. You get a gene from mum OR dad, not both. Any surviving set of genes forms a nested hierarchy back up to the sequence from which they all descend, whichever path they took. But anyway, I am not talking of family trees, but trees at species level and above. Despite sex operating within the species, descent resolves to a 'vegetative', branching structure above it.Chas D
January 24, 2012
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Fomr 3.1.1
There seems to be a general view on this forum that if we can’t actually go back and look, a hypothesis is untestable.
Elizabeth, the notion that something is 'testable' is the notion that you can slap it on a lab-table and doit or fail to do so. That is the common understanding of such things. As you have it, it is testable if we can navel-gaze over intuitions as a means of empirically testing a theory. And it must be empirical or it is not science. Remember well that Science is the intersection of Philosophy and Engineering. Absent the engineering, the empirical testing, it is just Philosophy. With all the good and bad that this entails.
Support for a hypothesis derived from a theory does not tell you that your theory is correct, but it does provide support for it.
If the hypothesis is not a necessary consequence of the theory then the hypothesis is based on mere intuition and is independent of the theory. Affirming consistency with the hypothesis cannot support the thoery it is independent from, and refuting a hypothesis on such a basis cannot refute the theory in any manner. This is fine if, again with Philosophy, the notion is that a Scientific theory is a Wetlanschauung; a philosophy; and non-empirical.
Lack of support for a hypothesis derived from a theory tells you that you need to adjust your theory. It doesn’t mean you need to throw out the whole thing, though.
Confirmation Holism, and an ugly thing. This is true whether or not the hypothesis was derived by necessity, or intuition about a weltanschauung.
“Darwinists” are often at fault for not making this clear. We do not, have, and will never have, a complete theory of how life as we observe it came to be.
Then you must agree, by the same argument, that one cannot state that Darwinsm is a fact. If it is not now, nor can ever be, complete and describe all possible inputs then it may reasonably state that it is necessary, but you have exlicitly stated that it is not, nor ever can be, shown as sufficient. At such a point if you make the leap from 'justified' to 'fact' then you have gone straight into the religious Faith side of things.
... and that is really where “Darwinists” depart from IDists. Not in rejecting ID, but in rejecting ID as the only reasonable default.
In general ID only states that mutations that have an external cause are necessary. Of course if you put internal, Darwin, and external mutations together then quite obviously the two together are sufficient. And thus via deductive hypothesis testing and confirmation holism: ID is Darwinism. And thus, in contradiction, Darwinism is sufficient and a fact that may be taught by government mandate without fear of theocracy so long as we include external mutations. If you wish to divorce ID and Darwinism you need to divorce Science and Philosophy; where Philosophy is, and should be, known as 'respectable' religioon when we assert a philosophy as a fact.Maus
January 23, 2012
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Chas- In order to have a nested hierarchy you need to have the "consist of and contained by" criteria: http://www.isss.org/hierarchy.htm
Nested and non-nested hierarchies: nested hierarchies involve levels which consist of, and contain, lower levels. Non-nested hierarchies are more general in that the requirement of containment of lower levels is relaxed. For example, an army consists of a collection of soldiers and is made up of them. Thus an army is a nested hierarchy. On the other hand, the general at the top of a military command does not consist of his soldiers and so the military command is a non-nested hierarchy with regard to the soldiers in the army. Pecking orders and a food chains are also non-nested hierarchies.
Animal kingdom consists of and contains animals. The alleged common ancestor of chimps and humans does not consist of nor conatain chimps and humans. As for molecular markers- there are only 4 possibilities for any one site and you have no idea how many times sites have changed and then changed back or converged. Trees are not necessarily a nested hierarchy. A family tree isn't a nested hierarchy.Joe
January 23, 2012
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And yes it all different representations of the same thing- the point is HOW they are all constructed- what is the basis for each drawing. And if the basis is descent with mod then the parent-child non-nested hierarchy is the drawing to use.
Well, you have seen HOW they are constructed. Look at a real tree. A real tree is also a tree of descent - lineages of cells. On a flat sheet, draw the buds, then follow the branches back. When you get to a node, draw the single branch around its two descendant buds. Follow other branches back, and again when you get to a node draw around it, encircling everything that depends on that branch, and so on. Bingo-you have a nested hierarchy. So, we know what a tree of descent gives - a nested hierarchy. We can reconstruct the branching pattern of the tree from the nested hierarchy alone - it is a 2D representation of the order of branching. And since we still have the tree, we can check that this is indeed the right branching pattern. Next, we look at some data where we ONLY have the buds (eg modern organisms). We try to draw a nested hierarchy. If we can't, we have NOT supported a tree. If we can, we HAVE. Simple. In practice, it's not always fully congruent, but the fundamental principle is that IF there was a real tree of descent, THEN the buds will group as a nested hierarchy. If it wasn't, they won't.
OTOH if you want to use some arbitrary method of construction then it is clear it is not based on descent with modification and that ruins your whole claim.
Arbitrary? What's arbitrary about grouping molecular markers held in common in a dataset? Could not be less arbitrary. The test is whether this non-arbitrary grouping produces a tree - it's based on descent, with or without modification. If a tree is recovered, common descent is strongly supported. If common descent wasn't routinely supported, this would be a worthless method of phylogenetic analysis.Chas D
January 23, 2012
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Sorry Chas...Joe
January 23, 2012
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Elizabeth:
It’s just the way he draws ‘em.
ALL are man-made constructs- ALL of them. And the way descent with modification works it is not a nested hierarchy. And yes it all different representations of the same thing- the point is HOW they are all constructed- what is the basis for each drawing. And if the basis is descent with mod then the parent-child non-nested hierarchy is the drawing to use. OTOH if you want to use some arbitrary method of construction then it is clear it is not based on descent with modification and that ruins your whole claim.Joe
January 23, 2012
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And guess what? Tiktaalik was not found between the two eras. Elizabeth:
Yes, it was.
No, it was not. It was found after tatrapods already existed. he was looking for something that existed before tetrapods existed.
8 is between 6 and 9, right?
By that analogy, Shubin found 11. We do not have any evidence Tiktaalik lived before tetrapods. Shubin was looking for something that existed before tetrapods. So simple my 9 year old gets it.Joe
January 23, 2012
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Eric B Knox, “The use of hierarchies as organizational models in systematics”, Biological Journal of the Linnean Society (1998), 63: 1–49 Descent with modification would lead to a hierarchy based on “first life”, which as you can see is not a nested hierarchy- that is if you bother to read the paper.
It's just the way he draws 'em. Drawing a species family tree - the cone with 'first life' on the left and 'modern life' on the right - is not a nested hierarchy, it is true, any more than a line of babushka dolls on a shelf is nested. But stack them, and they are. See fig 4-6 on page 12. Take a cone of descent (Fig 4), turn it end-on (Fig 5g), and group the latest descendant inside its recent ancestors, then draw those ancestors' ancestors around them and so on, and the hierarchy is revealed, nested at the base of the cone. Fig 4 is the non-nested hierarchy of parent-child couplings. Fig 5 is the succession of nested hierarchies that pattern of descent would yield. Fig 6 is the 'coupled model', where he attempts to draw the descent hierarchy in a way that yields the nested hierarchy in cross-section. It's just different ways of representing the same tree of descent. The point for cladistics is that you do not have the tree (fig 4), you only have the cross-section of current organisms (fig 5a-g, the nested hierarchy you would recover at successive points in time). But (if you are lucky) you have enough information in fig 5 (nested) to reconstruct figs 4 (non-nested) and 6 (coupled).Chas D
January 23, 2012
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and after there were fish
There are still fish.Elizabeth Liddle
January 23, 2012
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then you have to look between the two eras, just as Shubin said. And guess what? Tiktaalik was not found between the two eras.
Yes, it was. 8 is between 6 and 9, right? It is also between 4 and 9. Turns out we now have evidence for tetrapods at 5 as well. Cool, but that doesn't invalidate Shubin's prediction or his find.Elizabeth Liddle
January 23, 2012
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Yeah, I admit that you do know quite a bit about silly arguments, but in this case your example does not fit. If we were to find Tiktaalik-like things in strata before there were tetrapods and after there were fish, then yes, Tiktaalik was just a very long-lived transitional. But according to Shubin he wanted to find something that existed between the time of fish and the time of tetrapods:
Let’s return to our problem of how to find relatives of the first fish to walk on land. In our grouping scheme, these creatures are somewhere between the “Everythings” and the “Everythings with limbs”. Map this to what we know of the rocks, and there is strong geological evidence that the period from 380 million to 365 million years ago is the critical time. The younger rocks in that range, those about 360 million years old, include diverse kinds of fossilized animals that we would recognize as amphibians or reptiles. My colleague Jenny Clark at Cambridge University and others have uncovered amphibians from rocks in Greenland that are about 365 million years old. With their necks, their ears, and their four legs, they do not look like fish. But in rocks that are about 385 million years old, we find whole fish that look like, well, fish. They have fins. conical heads, and scales; and they have no necks. Given this, it is probably no great surprise that we should focus on rocks about 375 million years old to find evidence of the transition between fish and land-living animals.- Neil Subin pages 9-10
Those are his words, from his book. Even my 9 year old understands what it means...Joe
January 23, 2012
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Joe: does God not exist because some YEC believers have said the earth is 6000 years old and some have said 10,000? Your argument is every bit as silly.Petrushka
January 23, 2012
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Elizabeth:
He was specifically looking for animals with characteristics intermediate between known early tetrapods and late Silurian fish.
then you have to look between the two eras, just as Shubin said. And guess what? Tiktaalik was not found between the two eras.
That was the “gap” he wanted to fill, and he identified the time window in which he was likely to find those animals; the kind of deposit (litoral) in which they would be found; and where that kind of deposit happens to be close to the surface today.
His time window was the wrong window.
The answer was a particular spot in Greenland.
Wrong answer. Had he known that tetrapods exiosted at that time he would not have looked there. That is according to his logic and reasoning.
But what Shubin was looking for were animals that lived earlier than the earliest known tetrapods, not their likely descendents.
Exactly. Unfortunately that isn't what he found. And that is what I have been saying. What Shubin found lived many millions of years AFTER/ LATER than tetrapods.
He found the animals with the predicted characteristics in his predicted window.
So the theory predicts fish-> tetrapods-> fishapods? Or is it that you don't know what you are talking about. Shubin was looking for the water to land transition. For all he knows, because of the time-line of the find, he found a land-to-water transition. One more time- Shubin had his "window" based on two things he thought he knew- 1) the era in which there were fish and no tetrapods and 2) the era in which there were tetrapods. Those are HIS words, Elizabeth. However we now know that Shubin's "window" was the wrong window because his data points were wrong. And there is NOTHING in the theory of evolution that says transitional forms will exist millions of years AFTER the transition. If they existed millions of years after the transition there isn't anything preventing them from still existing. Data for the window was wrong- strange that you cannot grasp that simple fact.Joe
January 23, 2012
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1- He had no idea what characteristics he would find
Well, no. He was specifically looking for animals with characteristics intermediate between known early tetrapods and late Silurian fish. That was the "gap" he wanted to fill, and he identified the time window in which he was likely to find those animals; the kind of deposit (litoral) in which they would be found; and where that kind of deposit happens to be close to the surface today. The answer was a particular spot in Greenland. And there he found fossils of animals with exactly those intermediate characteristics.
2- There are transitional forms around today- ie fish that are air breathers and fish that can travel on land.
Yes, indeed, and they are probably descended from an ancestor that diverged from the those same early fish. But what Shubin was looking for were animals that lived earlier than the earliest known tetrapods, not their likely descendents.
Actually the “window” was totally shattered, which means his erasoning for looking where he did was also shattered.
Not sure what you mean by this. He found the animals with the predicted characteristics in his predicted window. That he might have found similar animals had he looked in slightly earlier strata is irrelevant. That someone has done so (or at least their tracks) is very exciting, and sheds new light on the timescale. It doesn't "shatter" anything, it merely fills in some more of the jigsaw puzzle in an unanticipated way. If the jigsaw is a picture of a tree, he found a particular piece of a branch. We know know that there is another branch that hadn't been known about earlier. In all likelihood there are probably a great many, but whether we will find fossils of all of them is unknown - not likely, though.
As he knew the only time period in which it is guaranteed to find a transitional form is BETWEEN two periods. What he found was after that and therefor could just be a hybrid.
Possibly. In some ways it probably was - speciation isn't a rapid process in geological terms, and some hybridisation will go on even after two populations have diverged. But if you are suggesting that Tiktaaliks are the hybrid offspring of some later tetrapod and a fish - well that seems unlikely to me. Does it really seem likely to you? But you are still not using the word "transitional" in the way generally used by palaeontologists, which maybe why you are (IMO) misinterpreting Shubin. And you are never, of course "guaranteed" to find a transitional form (on either the regular meaning of the word, or yours).
As I said either you think Shubin is a liar or just a story-teller… 3- There isn’t any reason why a species such as Tiktaalik today as opposed to just a mere twenty or more million years after the transition.
You seem to have missed out a word or so here. But if you mean "there isn't any reason why there aren't Tiktaaliks today", sure there isn't. There are fish today, after all.
That said “transitional form” is nothing more than “it looks like a transitional to me” and that is because of OUR classification system.
Well, no, it isn't. The concept is certainly closely bound up with the classification system, but fitting a new kind of organism into the classification system isn't just a question of saying "it looks like a transitional to me". It's usually done by quite sophisticated classification algorithms with statistical tests for the likelihood of any output tree.
BTW I am not using anologs- I am using what Shubin said aling with logic- the same logic Shubin used-> you do not go looking for evidence of the transition millions of years after-the-fact. And you cannot place some aribitrary time limit on the existence of the transitionals.
Well, your examples of wars and caterpillars were analogies, surely? And I'm precisely NOT "plac[ing] and arbitrary time limit on the existence of the transitionals". I'm saying that if you want to find a transitional form i.e. one that has characteristics of two existing taxa, then the first place to look (if you haven't found one) is in strata that lie, temporally, between the time you think the ancestral population lived, and the time you think the other population lived, because whether they subsequently surved for eons afterwards or went rapidly extinct, you know that they must have been extant during that intervening period. In other words, the window tells you where to look; it's the characteristics that tell you whether it's a transitional. If, instead of Tiktaaliks, Shubin and al had just found, say pandericthyses, or acanthostegas, they'd have found tetrapods from time between known populations of those two animals, but they wouldn't have found transitional fossils. However, in fact, they found Tiktaaliks, which were.
As I said either you think Shubin is a liar or just a story-teller…
I think he's neither. But I do think you have misunderstood him. Anyway, I appreciate the more civil tone. Thanks. Cheers LizzieElizabeth Liddle
January 23, 2012
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Eliabeth:
Because clearly in this case there was reason to expect a time limit (there are no living animals that have the intermediate characteristics proposed).
1- He had no idea what characteristics he would find 2- There are transitional forms around today- ie fish that are air breathers and fish that can travel on land. 3- There isn't any reason why a species such as Tiktaalik today as opposed to just a mere twenty or more million years after the transition.
It turns out he made that window slightly narrower than it need have been. Didn’t matter – he still found them.
Actually the "window" was totally shattered, which means his erasoning for looking where he did was also shattered. As he knew the only time period in which it is guaranteed to find a transitional form is BETWEEN two periods. What he found was after that and therefor could just be a hybrid. That said "transitional form" is nothing more than "it looks like a transitional to me" and that is because of OUR classification system. BTW I am not using anologs- I am using what Shubin said aling with logic- the same logic Shubin used-> you do not go looking for evidence of the transition millions of years after-the-fact. And you cannot place some aribitrary time limit on the existence of the transitionals. As I said either you think Shubin is a liar or just a story-teller...Joe
January 23, 2012
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then why didn’t he just go to a local stream and find one? Heck if there isn’t any time limit then they should be still be here.
Because clearly in this case there was reason to expect a time limit (there are no living animals that have the intermediate characteristics proposed). Hence his later boundary. He needed to look between the earliest likely date and the latest likely date. It turns out he made that window slightly narrower than it need have been. Didn't matter - he still found them.
And again Shubin did NOT say that he was looking for a transitionl fossil, you are pathetically mistaken. He said he was looking for evidence of THE TRANSITION.
Well, finding a transitional fossil is evidence that the transition occurred, and, moreoever, informative about the nature of the transition. Your analogies are not analogous. We are talking about a branching tree here, not a single timeline. And I'm sorry, but I simply do not accept that you have "refuted" anything. I am not ignoring your posts (though I said I would), as you can see, but I'm not going to address every one.Elizabeth Liddle
January 23, 2012
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elizabeth "Well, I gave you an example – a gene that was common to chimps and chickens but not found in any other primate" an erv called herv-k was found in gorila and chimpanzee but not in humans. they have also 100 copies ofervs called pterv1 and not a single one in humans! we found a slug with genes for photosynthese and more. the evolution is wrong? "Take, for instance, the adoption of an innovation such as ABS, or air conditioning in many lines simultaneously, not just the lineage in which it was first introduced" its called "convergent evolution" and living organisem have this also. the eye was evolved somthing like 40 times without a commondesent. "If data that cannot be explained by the current version of the theory are found, then the theory has to give" but like i sayed, anything can fit to the theory. there is no spot that you will say: "the theory is now false"mk
January 23, 2012
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Well Elizabeth I have provided support for my claim. OTOH you have provided nothing. Here it is- AGAIN: Eric B Knox, "The use of hierarchies as organizational models in systematics", Biological Journal of the Linnean Society (1998), 63: 1–49 Descent with modification would lead to a hierarchy based on "first life", which as you can see is not a nested hierarchy- that is if you bother to read the paper.Joe
January 23, 2012
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Feel free, Joe. But I remain of view that it is one of a list of things you do not understand. I guess we will have to agree to differ.Elizabeth Liddle
January 23, 2012
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No Elizabeth, you have not responded to what I have posted.
Firstly, if you accept that “transitional” populations can survive, relatively unchanged, long after the “transition” then your only real criticism of Shubin seems to be that he set the earliest boundary of his critical window rather late. In other words, he set the window rather narrower than he need have done, and at the later (safer) end of it. That makes no difference to the success of his prediction.
then why didn't he just go to a local stream and find one? Heck if there isn't any time limit then they should be still be here. And again Shubin did NOT say that he was looking for a transitionl fossil, you are pathetically mistaken. He said he was looking for evidence of THE TRANSITION. The War of 1812-> if I wanted to find evidence for the transition between peace and the war of 1812 do I look in documention for the year 1850 or do I look in documentation that pre-dates the war? If I wanted to study the transition between two US Presidents do I focus my study on the period two years after the election? If I wanted to study the transiton between caterpillars and butterflies, what am I doing wrong by studying what butterflies eat? ??? And nice of you to ignore all of other posts refuting your nonsense of this...Joe
January 23, 2012
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I have responded to it, Joe, in 7.1.1.1.4. I will rephrase here: Firstly, if you accept that "transitional" populations can survive, relatively unchanged, long after the "transition" then your only real criticism of Shubin seems to be that he set the earliest boundary of his critical window rather late. In other words, he set the window rather narrower than he need have done, and at the later (safer) end of it. That makes no difference to the success of his prediction. Secondly, in response to your repeated claim that:
And yes a transitional HAS to be found- IN TIME- between the alleged parent and alleged child species. And yes parent, transitional and child species can overlap- all transitionals can overlap. However any given transitional absolutely HAS to exist (or had to have existed) between the alleged parent and alleged child.
I am simply disagreeing that this is how palaeontologists use the term "transitional". It normally does not refer to a fossil that is directly inline between "parent" and "child" population anyway, and need not even be from a population that lived between those two populations in terms of time. For example, to take the definition given in Wiki:
A transitional fossil is any fossilized remains of a lifeform that exhibits characteristics of two distinct taxonomic groups. A transitional fossil is the fossil of an organism near the branching point where major individual lineages (clades) diverge. It will have characteristics typical of organisms on both sides of the split, but because of the incompleteness of the fossil record, there is usually no way to know exactly how close it is to the actual point of divergence.
"Near the split" does not necessarily mean near it in time but near in characteristics.Elizabeth Liddle
January 23, 2012
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Again, I know all of that and it does not change anything I have posted.Joe
January 23, 2012
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Elizabeth:
You certainly don’t go looking for a transition before you think it had occurred.
You need to know when it occurred. ya see according to Shubin he thought he was looking in strata that pre-dated tertrapods. He was wrong.
You can look after it, for as long as you like, though (hence “living fossils”).
That is false as there isn't anything that says transitional forms should remain in existence millions of years after the transition occurred. Obvioulsy you are just making stuff up again.
That’s because a “transitional fossil” is not an actual populatoin that is directly between some known ancestor and some known modern (or later) population, but which represents a population that branched off between the two and has intermediate characteristics.
Again he did NOT say he was looking for a transitional fossil. He said he was looking for evidence of THE TRANSITION and he said he was looking for evidence of the transition is strata in which he thought it occurred. However we now know the transition occurred much earlier which means he was looking in the wrong place.
So where would you expect to find tetrapods with the fishiest characteristics?
Only in strata between the transition of fish and tetrapods, which is where Shubin thought he was looking. Yet he was wrong.
In litoral deposits dating from not too long (but it doesn’t matter exactly how long) after the conjectured divergence.
1- It was at least many millions of years after and 2- No one even knows when it occurred. So you lose, again.Joe
January 23, 2012
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Again, the estimate of the transition period was made on the basis of fossils found prior to Tik. More data has obviously widened the window.Petrushka
January 23, 2012
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Elizabeth, I read what you posted and it is irrelevant to the point I am making and does not even address what Shubin said. Now in his book either he was lying or making up a story but according to what he said he would not have been looking where he did if he knew that tertrapods already existed in strata much earlier. IOW Liz you aren't responding to me now, so if you run away there won't be any difference. So I will keep repeating what I say until you actually respond to it and stop with the irrelevant distractions.Joe
January 23, 2012
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Well, perhaps you could take the time to read what I actually posted, rather than just repost what you already posted. Because there really isn't any point in responding to you unless you do.Elizabeth Liddle
January 23, 2012
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It would help to distinguish what I said from what I did not say. I did not say that the inability to observe the pre-biotic conditions of earth disproves unguided abiogenesis. What I said was that Darwinists hold, as an incontrovertible fact, that the advent of life on earth was an unguided process, that this belief affects their argumentation a related topic, and that that in the face of our inability to observe anything at all about conditions that held when this process took place, their certainty is unjustified. And yes, I do hold that any claim that "X happened at a certain point in the past" must necessarily be tentative when neither X nor anything like X has been observed, and the conditions in the past are not knowable beyond the vaguest guesswork. I most certainly did not say that unguided abiogenesis was conclusively disproven, merely that it is not conclusively proven. But if we are going to go for testable hypotheses, fine: What will we observe if life on Earth began as a result of unguided processes, with no involvement of any kind by any intelligent agency? What will we observe if life on Earth began as a result of processes of which one or more were guided by intelligent agents? Either side can answer these ones.EvilSnack
January 23, 2012
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