The Panda's Thumb Legacy Archive — pandasthumb.net

Trollart on Tiktaalik

Posted 5 April 2006 by Nick Matzke

People have been talking about the discovery of two more new gaps in the fossil record of the fish-tetrapod transition, which occurred when scientists found a predicted intermediate fossil, which they named Tiktaalik. Well, Alaskan artist Ray Troll, at his website TrollArt.com, has gone one better and illustrated the T-shirt version already: Hat-tip to Glenn Branch. Glenn also asks: who is the third hand?

51 Comments

Sir_Toejam · 5 April 2006

who is the third hand?

sympathetic wife? Man, that slogan shows that there is finally someone who understands what ichthyologists like myself have been saying for years. "Embrace your inner fish" Indeed.

C. Hoffman · 6 April 2006

That must be the hand of God.

Stoffel · 6 April 2006

Wouldn't that be one more gap, not two?

Nick Matzke · 6 April 2006

I suppose that is a way of looking at it -- one net new gap. But, if the new fossil is in the middle of the old gap, then that old gap no longer exists, instead it is replace with two new gaps, neither gap identical to the original gap, whatever that means for things that are after all defined negatively.

This message was brought to you by The Gap.

Renier · 6 April 2006

Wouldn't that be one more gap, not two?

Nee jong. Creationists will ask: 1) Where is the transitional fossil between fish and Tiktaalik? 2) Where is the transitional fossil between Tiktaalik and tetrapods? Same old story from the same old crowd. Does anyone know if Tiktaalik had a swim bladder? Swim bladders appears to have evolved from primitive lungs. It could then be that this critter started using the swim bladder as a primitive lung again.

Tiktaalik had a mobile neck and had lost the bony coverings of the gills that fish use to fan water to maximise their oxygen intake. These suggest that the fish may have been at least partly air-breathing, like modern tetrapods (Nature, vol 440, p 757 and p 764).

Moses · 6 April 2006

Comment #95080 Posted by Nick Matzke on April 6, 2006 02:34 AM (e) I suppose that is a way of looking at it --- one net new gap. But, if the new fossil is in the middle of the old gap, then that old gap no longer exists, instead it is replace with two new gaps, neither gap identical to the original gap, whatever that means for things that are after all defined negatively. This message was brought to you by The Gap.

That's an interesting way to look at it. It would be two "new" gaps, with the retirement of the "old" gap in between which would, in effect, be an net increase of one gap. Sort of a gap de-evolution as generations of gaps spawn more and more gaps of less & less creationist fitness for exploitation. Still, they won't be happy until you can provide a list of begats from the first cell.

Johnny Vector · 6 April 2006

That's an interesting way to look at it. It would be two "new" gaps, with the retirement of the "old" gap in between which would, in effect, be an net increase of one gap.

— Moses
No, no, no! No retirement of the old gap. There are two new gaps, yes, but not only are these fossils actually previously known fish species, but the new species they do represent is not transitional between fish and tetrapods anyway. So a net gain of three gaps. The Darwinists are losing ground so fast that evolution will be dead within the next decade! Perhaps not all at the same time, but I'll wager the traditional bottle of single-malt scotch that all of the above arguments appear at the usual sites within a month.

Katherine · 6 April 2006

The creationists simply need to adopt a new mathematically-inclined approach. Instead of transitional fossils, think rational numbers. Not only is there a gap between each rational, but there is an infinity of such gaps.

If any creationist wants to pick this up and run with it, may I suggest the 'irrational' arguement?

Dizzy · 6 April 2006

I'm surprised that nobody has called attention to the fact that this finding may refute what scientists consider a well-established fact:

"Contrary to what most people say, the most dangerous animal in the world is not the lion or the tiger or even the elephant. It's a shark riding on an elephant's back, just trampling and eating everything they see."
- Jack Handey

Some of these fossils were nine feet long. They might have gotten bigger. Just imagine...an elephant-shark.

Peter Henderson · 6 April 2006

As expected:

It will be interesting to see what they make of it. Just another "Kind" of fish maybe ?

Bruce Thompson GQ · 6 April 2006

Nick says: "I suppose that is a way of looking at it --- one net new gap."
Since no one has made the bad joke yet I will. Just a little bit more and it's a one newt gap. Delta Pi Gamma (Scientia et Fermentum)

Alann · 6 April 2006

See evolution is full of gaps: life begins ? Fossil(1) ? ... ? Fossil(n) ? Humans Then number of gaps = n+1, the more fossils the worse it gets. By this reasoning ID is much better: life begins (insert miracle here) Humans See only one gap, neatly filled. Just toss aside rational thought and it makes perfect sense. Of course ID sometimes gets confused:

ID does not preclude evolution per se; it challenges the notion that evolution happened by blind chance.

— Uncommon Descent
Someone hasn't been reading "Of Panda's and People", which states clearly all life was created as is.

Bumper Medallion · 6 April 2006

I want a GOLD metalic outline version of Tiktaalik for my bumper...with jaws open, and taking a step up.

djw · 6 April 2006

First moths, now fish? I thought this was about the predictive nature of evolution, not the nature of procreation of evolutionists.

The moth (nature was the first google match):

http://www.pbs.org/wnet/nature/deepjungle/lesson_plan.html

In 1862, Charles Darwin studied a bizarre orchid found on Madagascar. Darwin predicted that its survival probably depended on a gigantic moth with a 12-inch tongue. In this program, biologist Phil DeVries uses an infrared camera to finally catch this strange insect in action.

Sir_Toejam · 6 April 2006

This message was brought to you by The Gap.

ummmm, so would we call an IDiot who touts these gaps, a Gap troll? sorry, couldn't resist.

Sir_Toejam · 6 April 2006

Still, they won't be happy until you can provide a list of begats from the first cell.

i got news for ya. They'll NEVER be happy. don't even try.

Sunny Wong · 6 April 2006

Oh man now I GOTTA get one of these shirts...

Stevaroni · 6 April 2006

Still, they won't be happy until you can provide a list of begats from the first cell.
This is way off-topic, but since you mention begatting (begetting?), and since there are plenty of people on this group who are pretty steeped in the Bible as literature, I'm wondering if anyone can explain Matthew 1 to me. That's the part where they go over the genealogy of Jesus, starting at Adam, begatting down through Moses, David, etc. As a youngster, I used to sit in church listening to this thinking "Great family tree little J has there, but how does it make a fig of difference, seeing that one; he's adopted, and two; his biological father pretty well trumps his stepfather anyway, who has, um slightly less status than some of his ancestors". I was never able to get a good answer out of any priest to whom I asked this question, so I'm actually really curious.

Steve Reuland · 6 April 2006

It will be interesting to see what they make of it. Just another "Kind" of fish maybe ?

It is either 100% fish, or 100% tetrapod. Some creationists will call it a fish, and others will call it a tetrapod, but they'll all agree that it can't be something in-between. Or maybe they'll get really creative and call it 100% Tiktaalik, thereby proclaiming that it cannot, by definition, be transitional.

Henry J · 6 April 2006

But does it taste like chicken?

Sir_Toejam · 6 April 2006

well, that would be the definitive test. If it tasted more like chicken than fish, that would make it closer to tetrapods.

Damn, if only roasted fossil tasted like anything other than rock...

KP · 6 April 2006

Pretty good layman's treatment of it in the NY Times

http://www.nytimes.com/2006/04/06/science/06fossil.html

You would think the creationists would walk away with their vestigial tails between their legs, but instead you get Duane Gish's whining about no "transitional" fossil between invertebrates and vertebrates.

Stephen Wells · 6 April 2006

This is way off-topic, but since you mention begatting (begetting?), and since there are plenty of people on this group who are pretty steeped in the Bible as literature, I'm wondering if anyone can explain Matthew 1 to me. That's the part where they go over the genealogy of Jesus, starting at Adam, begatting down through Moses, David, etc. As a youngster, I used to sit in church listening to this thinking "Great family tree little J has there, but how does it make a fig of difference, seeing that one; he's adopted, and two; his biological father pretty well trumps his stepfather anyway, who has, um slightly less status than some of his ancestors".

— Stevaroni
Simply put, the whole idea of Jesus being "of the house of David" only works through his descent from Joseph. IIRC the whole "virgin birth" thing is only in one of the Gospels anyway, and is based partly on a confusion between the terms for "virgin" and "young woman:, and partly on the general tendencies to folk heroes to have divine parentage. I think it's a good idea to separate Christianity, in the sense of thinking it's a good idea to heal the sick, feed the hungry, and be merciful, from Jesusism, which is all about the divine parentage and the sacrificial death and resurrection and is indistinguishable from, say, Mithraism or the Isis cults. Now back to our regularly scheduled amphibians.

B. Spitzer · 6 April 2006

This is way off-topic, but since you mention begatting (begetting?), and since there are plenty of people on this group who are pretty steeped in the Bible as literature, I'm wondering if anyone can explain Matthew 1 to me. That's the part where they go over the genealogy of Jesus, starting at Adam, begatting down through Moses, David, etc.
The Gospel of Matthew was written for a Jewish audience. Matthew used a lot of the exact same material as Mark and Luke (Mark was presumably a source for both Luke and Matthew), but Matthew put in many references to the existing Jewish scriptures, to convince devout Jews that Jesus was the fulfillment of what we now call the Old Testament. The list of "begats" splits Jewish history up into three sections of fourteen "generations" each: the time from Adam until David, who was of course the central political figure in Jewish history; then the time until the exile in Babylon, which was a defining event for the nation of Israel; then the time from the Babylonian exile until Jesus. (What's ironic, at least for a blog devoted largely to opposing Biblical literalists, is that this list of "begats" isn't accurate. I'm afraid I don't recall the details, but Matthew had to play around with the genealogy a bit to get it to fit the neat pattern that he wanted. Which, I think, implies that even the writers of the New Testament didn't look at the Bible as something that should always be taken literally.) Carol, don't even comment on this. Thanks.

Steviepinhead · 6 April 2006

What are we saying here?

That Carol's not just as good an amphibian as the rest of us?

Gary · 6 April 2006

Is it just me or is Ken Ham a dead ringer for the old comic strip character Ally Oop? Which bestows some kind of irony on the title of his article '"Missing link"?', no?
~Gary

melvin · 7 April 2006

Ha

Bob the Fish · 7 April 2006

Which came first, this commentary or the one that PZ wrote about the same subject? I guess I could check the time stamp if there is one.

All too often the same repackaged commentary shows up on 3 or 4 websites. Is there a talking points memo somewhere?

JKC · 7 April 2006

TrollArt also has a song to go along with this story...

http://www.trollart.com/sound/devonianblues/index.html

check it out!

Peter Henderson · 7 April 2006

More from AIG:

As I suspected it's just another "Kind" of fish !

Deborah McLennan · 10 April 2006

OK, so let's finally get with the phylogenetics revolution! We are ALL Osteichthyes (bony fishes) and, within bony fishes, we are all Tetrapoda (four footed) ... in other words, the new species is a tetrapod fish ... there is no such thing as a "fish" unless you are willing to include ALL of the descendants of the bony fish's ancestor, which includes salmon, lung fish, frogs, mammals, turtles, crocs birds, lizards and snakes (among others) ... and the swim bladder evolved in the ancestor of bony fishes sooo, yes Tiktaalik has a swim bladder (and since it is a tetrapod, that bladder would be serve more as a functional lung than as a buoyancy organ). Swim bladders didn't evolve from primitive lungs - it appears that the swim bladder initially served as both a buoyancy organ and a gas exchange organ ... these two functions separated and became more buoyancy oriented in ray finned fishes and more gas exchange (lung) oriented in lobe finned fishes (coelacanths + lungfish + tetrapods) ... in conclusion, and much more important than the preceding pedantic blathering ... when will "embrace your inner fish" be T-shirt ready???

Sir_Toejam · 10 April 2006

when will "embrace your inner fish" be T-shirt ready???

thank god somebody else was thinking the same thing i was. damn important issue that!

Piltdown man · 19 April 2006

FYI, Matthew did reduce the generations leading to Jesus to three groups of 14. It was a traditional Jewish practice for helping in memorization.

Isaiah prophesied that the virgin would give birth. The Hebrew word used can indeed mean either virgin or young maiden, but when the Septuagint was written, some 200 years before Christ, the Greek word chosen for this passage specifically meant virgin, so that's what the Jewish scholars expected.

Read closely and you'll see a difference in the genealogies in Matthew and Luke. Most students of scripture believe Matthew's genealogy is Joseph's, running through Solomon, and Luke's is actually Mary's genealogy, the secondary line through David's son Nathan, even though she is not named herself. This would also keep the curse against Solomon's descendants, found in Jeremiah, from affecting Jesus.

SAMVIT · 17 May 2006

ALANN:
See evolution is full of gaps:
life begins ? Fossil(1) ? ... ? Fossil(n) ? Humans
Then number of gaps = n+1, the more fossils the worse it gets.

SAMVIT:
Not necessarily.How can you assume such an order of (?)s.Even if evolution were true, do we have any evidence that evolution leads to more complex organisms?

Why not this way?
Human(1) ? Apes(2) ?........ ? Repitiles(x) ? Fishes(x+1) ?........micro-organisms(n) ?

Evoultion is full of gaps because it is assumes a seires without any evidence.

What is the evidence that apes could not have evolved from humans?

I am not saying that apes evolved from monkeys.But i am asking-- what makes us accept that a species is intermediate between another two? They can be just distinct and similar species.If any scientific way can be found out to acertain that a particular species is intermediate between another two then there is any use of finding new fossils. Other wise wasting time in finding new fossils is just a way to evade the real question.

THE REAL QUESTION IS "which species came after which?"

Until now evolution theory has-- begun with a presumption(of an order)-- Juggled by biology-- and continued as a science fiction-- Without any evidence( even after so many fossil records along with carbon dating)

Can some one help?

Warm regards
Samvitm@yahoo.co.in

Rilke's Granddaughter · 17 May 2006

THE REAL QUESTION IS "which species came after which?" Until now evolution theory has--- begun with a presumption(of an order)--- Juggled by biology--- and continued as a science fiction--- Without any evidence( even after so many fossil records along with carbon dating) Can some one help?

I'm not sure I understand the problem. Evolutionary theory does NOT begin with a presumption of order. A chronological ordering of species is derived data, based on the appearance of preserved morphological traces in the earth (and to some extent derived genotype histories). Geological ordering was understood well before Darwin, and the place of fossils determined the 'order' of species development based on that geological ordering. Radiometric dating then permitted accurate dating of the geological sequence which in turn permitted accurate dating of the species sequence. I might also note that carbon-dating is of trivial value in ordering species development; the majority of biodiversification is pre-50,000 BCE.

Rilke's Granddaughter · 17 May 2006

THE REAL QUESTION IS "which species came after which?" Until now evolution theory has--- begun with a presumption(of an order)--- Juggled by biology--- and continued as a science fiction--- Without any evidence( even after so many fossil records along with carbon dating) Can some one help?

— SAMVIT
I'm not sure I understand the problem. Evolutionary theory does NOT begin with a presumption of order. A chronological ordering of species is derived data, based on the appearance of preserved morphological traces in the earth (and to some extent derived genotype histories). Geological ordering was understood well before Darwin, and the place of fossils determined the 'order' of species development based on that geological ordering. Radiometric dating then permitted accurate dating of the geological sequence which in turn permitted accurate dating of the species sequence. I might also note that carbon-dating is of trivial value in ordering species development; the majority of biodiversification is pre-50,000 BCE.

Rilke's Granddaughter · 17 May 2006

FYI, Matthew did reduce the generations leading to Jesus to three groups of 14. It was a traditional Jewish practice for helping in memorization.

— Piltdown Man
An thereby eliminating any claim to veracity. Since we understand that the genealogy is merely one of rhetorical convenience, it is worthless as historical information.

Isaiah prophesied that the virgin would give birth. The Hebrew word used can indeed mean either virgin or young maiden, but when the Septuagint was written, some 200 years before Christ, the Greek word chosen for this passage specifically meant virgin, so that's what the Jewish scholars expected.

No, that's NOT what Isaiah prophesied. Isiah simply claimed that a young woman would give birth. The author of the gospel tried to force Jesus into this particular prophecy by misunderstanding the entire Isaiah passages.

Read closely and you'll see a difference in the genealogies in Matthew and Luke.

Actually it's pretty darn obvious; close reading isn't required.

Most students of scripture believe Matthew's genealogy is Joseph's, running through Solomon, and Luke's is actually Mary's genealogy, the secondary line through David's son Nathan, even though she is not named herself. This would also keep the curse against Solomon's descendants, found in Jeremiah, from affecting Jesus.

Nope. This is not the scholarly consensus. This is a reading favored by a small number of Biblical literalists who can't accept the idea that the passages in question are simply fictions invented to give Jesus the appropriate gravitas of descent. And all this is off topic and belongs on the Bathroom Wall.

Anton Mates · 17 May 2006

Until now evolution theory has--- begun with a presumption(of an order)--- Juggled by biology--- and continued as a science fiction--- Without any evidence( even after so many fossil records along with carbon dating) Can some one help?

— SAMVIT
On the off chance that you'd like to know more about dating methods and how they're used to cross-check each other, you might look at the talk.origins FAQ on radiometric dating and the geological timescale. Suffice to say, there are several independent methods of dating that give mutually consistent results. Some predate Darwin, many were used by geologists who doubted evolution (back when there were many such), and modern geologists have no particular compulsion to support evolutionary theory. So it's not very plausible that the entire field of geological dating is one enormous Darwin-serving fraud.

SAMVIT · 18 May 2006


Rilke's Granddaught:
A chronological ordering of species is derived data, based on the appearance of preserved morphological traces in the earth (and to some extent derived genotype histories)...and the place of fossils determined the 'order' of species development based on that geological ordering.

SAMVIT:
Can you clarify it some more-- with reference to the following?

Even if we are sure about geological ordering, still how does it DEFINITELY tell us that species DEVELOPED in that way? Did the species realy develope in that order or did they got extinct in that order?

e.g:
Say humans gets extinct before the apes.After say a million years...both the human and ape fossils will be found below a certain depth but above this layer we should find ape fossils but not any human fossils.

Would that surely indicate that Apes evolved from humans?
If yes, then extrapolating the same logic we can use the geological ordering to determine the order of SPECIES DEVELOPEMENT. If no, then how can this method be relied upon to predict the order of SPECIES DEVELOPEMENT?

As per my understanding the method of geological ordering can be used -- only to determine the period -- atleast before which -- the species did not get extinct.

Can someone please explain me how(please consider my above argument) geological ordering can be reliably be used to determine --- The order of species DEVELOPEMENT?

Moreover,at some places the fossils are found in an order which is approximately reverse of the order in which they are mentioned in the evolution theory.In addition to that, at these places, there is no sign of one layer of earth sliding below another.How does evolution theory explain this?

Thank you.

Samvit

Rilke's Granddaughter · 18 May 2006

Rilke's Granddaught: A chronological ordering of species is derived data, based on the appearance of preserved morphological traces in the earth (and to some extent derived genotype histories)...and the place of fossils determined the 'order' of species development based on that geological ordering. SAMVIT: Can you clarify it some more--- with reference to the following? Even if we are sure about geological ordering, still how does it DEFINITELY tell us that species DEVELOPED in that way? Did the species realy develope in that order or did they got extinct in that order? e.g: Say humans gets extinct before the apes.After say a million years...both the human and ape fossils will be found below a certain depth but above this layer we should find ape fossils but not any human fossils. Would that surely indicate that Apes evolved from humans? If yes, then extrapolating the same logic we can use the geological ordering to determine the order of SPECIES DEVELOPEMENT. If no, then how can this method be relied upon to predict the order of SPECIES DEVELOPEMENT?

— SAMVIT
Again, I'm not entirely clear about the problem. The first appearance of fossils is also a factor in the determination of lineage. As an example, let's say we find the following fossils in situ situation. I will number the layers in order from TOP to BOTTOM. Layer 1: Chimpanzees Layer 2: Chimpanzees, Humans Layer 3: Chimpanzees, Humans Layer 4: Humans (Note that I did not specify 'apes' since humans are, after all, simply another species of apes). Given that sequencing, and given the obvious morphological correlations between chimpanzees and humans, we could conclude that chimps evolved from humans. It is far more likely that we would find something similar to: Layer 1: Chimpanzees Layer 2: Chimpanzees, Humans Layer 3: Chimpanzee-like fossils, Human-like fossils Layer 4: Something that looks both like chimps and humans From this we would probably conclude that both chimps and humans evolved from a common ancestor. It is important to remember that the first appearance of a fossil-species is as important as the last traces of that species.

As per my understanding the method of geological ordering can be used --- only to determine the period --- atleast before which --- the species did not get extinct.

Not true. And more importantly, the appearance of fossils does not indicate that the species is extinct; merely that a sample of the species is preserved. In other words, the presence of a fossil in a given dated strata merely permits us to state that the species was extant at that point in time - we can't really tell from the fossil record when a species went extinct.

Can someone please explain me how(please consider my above argument) geological ordering can be reliably be used to determine ---- The order of species DEVELOPEMENT?

I just did. If it's still not clear, ask more questions.

Moreover,at some places the fossils are found in an order which is approximately reverse of the order in which they are mentioned in the evolution theory.In addition to that, at these places, there is no sign of one layer of earth sliding below another.How does evolution theory explain this?

Complete columnar inversion without 'sliding' is possible. In general, however, traces of the inversion process can be found. Are you referring to any specific instance?

Anton Mates · 18 May 2006

This will overlap quite a bit with RGD's response, but:

As per my understanding the method of geological ordering can be used --- only to determine the period --- atleast before which --- the species did not get extinct.

— SAMVIT

Can someone please explain me how(please consider my above argument) geological ordering can be reliably be used to determine ---- The order of species DEVELOPEMENT?

Three important things here: 1) Geological dating gives you just as much information about when a species appeared as when it disappeared. If you find a fossil dated to, say, 35 mya, you know that that species went extinct sometime after that date, but you also know that it first appeared sometime before that date. As RGD says, you can never be sure how long the species persisted after its most recent known fossil, nor can you be sure how long it existed before its earliest fossil. But if you find many fossils you can make a reasonable estimate of its span of existence. 2) Dates of appearance are if anything more important than dates of extinction in figuring out which species gave rise to which. By analogy, suppose you've got the vital statistics on the members of some family, and you want to figure out who's the child of whom. Would you use their dates of death? Well, those aren't all that useful, because a child can have an earlier date of death than a parent, if it happens to die young. On the other hand, dates of birth are really useful because of course a parent must be born before their child. So take, say, Homo neanderthalis (assuming Neanderthals are a separate species--there's still a debate on but I think most anthropologists are leaning in that direction now) and Homo sapiens. Obviously we've outlasted Neanderthals. Does that mean they're our ancestors? Probably not, because Neanderthals also appeared 1-200,000 years after the first H. sapiens. So the Neanderthals are probably an offshoot of H. sapiens, not the other way around; they just failed to outlast us. 3) Fossilization is so rare, and the fraction of the earth's crust we've searched for fossils is so small, that we haven't found even a hundredth of the large animal/plant species that were alive at any given time. In fact, we probably never will. So we usually assume, on statistical grounds, that any two species we do have fossils of were probably not direct parent & daughter species. E.g. the ancestors of modern birds were therapsid dinosaurs related to the dromeosaurids, but we probably don't have the exact dinosaur species which was their ancestor from any given time. So when you ask about who evolved from who, just keep in mind that paleontologists will disagree with most statements like "[Known species 1] evolved from [known species 2]." (The Neanderthal/sapiens question is an exception, perhaps, because the genus Homo is so recent and so widely studied that we have a relatively huge fossil record for it.)

Moreover,at some places the fossils are found in an order which is approximately reverse of the order in which they are mentioned in the evolution theory.In addition to that, at these places, there is no sign of one layer of earth sliding below another.How does evolution theory explain this?

Echoing RGD, if you have a specific example of this we'd love to hear about it. In fact, pretty much any paleontologist in the world would love to hear about a seriously and puzzlingly out-of-place fossil layer--a paper on that sort of thing could make their career!

Glen Davidson · 18 May 2006

SAMVIT: Can you clarify it some more--- with reference to the following? Even if we are sure about geological ordering, still how does it DEFINITELY tell us that species DEVELOPED in that way? Did the species realy develope in that order or did they got extinct in that order?

We don't know DEFINEITELY that species DEVELOPED in that way. This is one of the biggest problems that we have in propagating science among the public, that nothing is ever "definitely" shown to be the case. This goes back to Hume and his comments on the impossibility of really knowing that a cause observed in one case is also the cause acting in another case. Or more exactly, we can't definitely demonstrate cause even in the cases that we observe "directly". Even within the scientific meaning of "demonstration", we do not believe that we can "demonstrate" that one species known only from fossils gave rise to another species. Tiktaalik is not considered to be the ancestor of amphibians and other vertebrates that evolved from amphibians, it is considered to be an intermediate form closely related to the ancestor of amphibians. It shows us what the ancestor of amphibians was like, without necessarily being the parent species of any later known species at all. It is possible that it did give rise to later invertebrates, but we can hardly know that. What is important about Tiktaalik and other intermediates is that they fit the overall patterns expected from evolution via natural selection+. This is often a difficult notion to get across to people, the fact that we don't need to follow exact events in the past, what we need to be able to do is to make sense of the past with our models. Tiktaalik fits perfectly into the evolutionary scheme--as do almost all (perhaps we could say "all", depending on what we do with anomalous data--which exists across the sciences) other organisms--apparently being a part of the radiation of tetrapods.

e.g: Say humans gets extinct before the apes.After say a million years...both the human and ape fossils will be found below a certain depth but above this layer we should find ape fossils but not any human fossils. Would that surely indicate that Apes evolved from humans?

No, it would not. Indeed, apes did not evolve from humans, and humans did not evolve from apes (not modern apes anyway--there does not seem to be a true consensus whether or not the last common ancestor of apes and humans should be called an "ape"). One has to utilize both morphology and dates coming from an adequate fossil record to make a good case for derivation of one species from another one. Modern apes are specialized derivatives of what was probably a more general ancestor, and so are humans. It would not be easy to derive humans from extant apes. That is to say, if we found chimp or gorilla fossils earlier than human fossils, we would not suppose that chimps or gorillas were the ancestors of (or closely related to the ancestors of) humans. Modern apes appear to be too specialized to be the ancestors of humans, or at least they'd need quite a long evolutionary development to get to the stage where they'd even appear to be the ancestors of humans. No, it is not just a matter of which fossils come first in the record, or we might suppose that crocodiles evolved into humans. One has to show that later features may be derived from earlier features. This is why Australopithecines are understood as very good candidates for ancestors of humans, for they do not appear to have features that are inconsistent with the evolution of human features (or actually, some robust types do seem unlikely to be the ancestors of humans, while the "gracile" types do have the proper morphologies to be human ancestors).

If yes, then extrapolating the same logic we can use the geological ordering to determine the order of SPECIES DEVELOPEMENT. If no, then how can this method be relied upon to predict the order of SPECIES DEVELOPEMENT?

That method is not used alone to demonstrate species developing from other species. Like I said, chimps have been shown not to be ancestral to humans, and this has been apparent for a very long time. Detailed morphological investigations have to be used to show ancestral types. As such, we can even understand the currently living lobe-finned fishes as (slightly modified in morphology) intermediates, "living links", that are reasonably closely "related to" our ancestors that existed far earlier than did any primate.

As per my understanding the method of geological ordering can be used --- only to determine the period --- atleast before which --- the species did not get extinct.

It shows the earliest known appearance of certain taxa, at least the earliest known appearance in the fossil record. It also shows the last known occurrence of many extinct taxa. As such, it gives us a range in which we can look for the ancestors and descendants of various organisms. But showing actual evolutionary developments (within the range of resolution) requires morphological comparisons, and considerations of whether one form is too specialized to give rise to another--or not.

Can someone please explain me how(please consider my above argument) geological ordering can be reliably be used to determine ---- The order of species DEVELOPEMENT?

It cannot do so by itself. We would not have "missing links" if we used geological ordering alone to determine the order of species development. What was great about Tiktaalik is that, because of the other intermediate forms known, plus our knowledge of how fast, roughly, evolution occurs, paleontologists were able to look in just the right age of rocks where fossils which showed the desired developments were likely to occur. And they found what they were looking for. But Tiktaalik was only one of many fossils that they found. They knew that Tiktaalik was representative of tetrapod development and radiation by studying the morphology of its fossilized bones.

Moreover,at some places the fossils are found in an order which is approximately reverse of the order in which they are mentioned in the evolution theory.In addition to that, at these places, there is no sign of one layer of earth sliding below another.How does evolution theory explain this?

It doesn't. Reverse ordering and "out-of-place" ordering is known only from areas where tectonic activity has occurred. Some creationists like to claim that overthrusts and overturning have not been demonstrated in every case. Actually, it probably has been adequately shown in every case that has been investigated, and like I said, these things only appear in regions that have been tectonically active. You don't find these problems in the flat, undisturbed layers in the Grand Canyon, for instance. You only find them in areas like the Rocky Mountains, Appalachians, etc. Glen D http://tinyurl.com/b8ykm

Anton Mates · 18 May 2006

No, it would not. Indeed, apes did not evolve from humans, and humans did not evolve from apes (not modern apes anyway---there does not seem to be a true consensus whether or not the last common ancestor of apes and humans should be called an "ape").

— Glen Davidson
I didn't know there was any disagreement on that nowadays. Isn't standard phylogenetic procedure to include the common ancestor of a clade in that clade? Besides, our last common ancestor with chimps ought to nest well within the ape clade as a whole.

Glen Davidson · 18 May 2006

Until now evolution theory has--- begun with a presumption(of an order)

No, it simply recognized the order that was there. What would you think if you saw only invertebrates and fishes in ealier layers, dinosaurs in some later layers ("later" as judged by superposition), and mammals and birds mostly in the latest layers? The temporal ordering already existed, and creationists tried to work out the cause of the order by supposing that various creations and catastrophes occurred.

--- Juggled by biology---

And why did creationist Linnaeus devise a taxonomic scheme that suggests relatedness? Unfortunately for your biases, some of the predictions of evolution were fulfilled first, and only later was evolution itself thought up to explain the order that we see. Only then did people look for further evidence, and found it--notably, archaeopteryx in the 19th century. Archaeopteryx connected some of the observed taxonomoic relationships in a visible and evolutionarily-predicted way.

and continued as a science fiction---

You're going to have to learn to differentiate between sci-fi and science. Until then it is unlikely that you can be helped.

Without any evidence( even after so many fossil records along with carbon dating)

Carbon dating has very little to do with the evidence for evolution, in general and in particular. You're also going to have to learn what evidence is, since Darwin's own books were filled with much evidence for evolution. Since then, we've amassed much more evidence, especially the crucial genetic evidence discovered lately. Even if we had no fossil record whatsoever we'd know that evolution occurred. The fossil record is probably best at giving us an idea of the range of times needed for evolution, and at revealing what forms existed in the "branches" and "limbs" of radiation, and not only what exist presently as the ends of the "twigs".

Can some one help?

Only if you're asking real questions, and not insisting that pseudoscience trumps science. Glen D http://tinyurl.com/b8ykm

Glen Davidson · 18 May 2006

No, it would not. Indeed, apes did not evolve from humans, and humans did not evolve from apes (not modern apes anyway---there does not seem to be a true consensus whether or not the last common ancestor of apes and humans should be called an "ape").

— Anton Mates
I didn't know there was any disagreement on that nowadays.

Maybe there isn't, at least not among taxonomists. Hence the "seem" that I used. However, while we're all within "Hominidae", which is a scientific name, I have the impression that there is no exact definition of what an "ape" is. We just call this or that an "ape". "Great ape" and "lesser ape" seem to be defined by convention, at least. I could be wrong, mind you, but it seems like a problem with using conventional terms rather than the scientific names. I was thinking that the convention of calling our nearer ancestors "ape-like", and the convention of calling them "apes", has not cleared up, while the scientific names are settled for presently-known hominims. I see australopithecines called apes sometimes, and "ape-like" by others, and have assumed that both were possible because "ape" is not well-defined.

Isn't standard phylogenetic procedure to include the common ancestor of a clade in that clade?

— Anton Mates
I believe so, though I'm hardly the one to say. But is the "last common ancestor" an ape, or "ape-like"? Scientific names can be decided, while "ape" as far as I know is too ill-defined to be, well, definitive.

Besides, our last common ancestor with chimps ought to nest well within the ape clade as a whole.

— Anton Mates
Is there an "ape clade"? If there is, then no doubt you are correct. If "ape" is only an ill-defined conventional term, then we have some freedom to consider ourselves to have "evolved from" or "evolved away from" apes and the characteristics that they share. Cladistically, your point stands, no doubt. I'm just not sure that "ape" is a term that fits cladistics with any precision. Glen D http://tinyurl.com/b8ykm

Henry J · 18 May 2006

Re "I'm just not sure that "ape" is a term that fits cladistics with any precision."

Are there any cases of a non-ape species thought to be descended from a species normally called an ape? If not then it sounds like a clade to me. :)

Henry

Glen Davidson · 18 May 2006

Re "I'm just not sure that "ape" is a term that fits cladistics with any precision."

— Henry J
Are there any cases of a non-ape species thought to be descended from a species normally called an ape?

Well, yes. I mentioned Australopithecines, and would have mentioned humans if they didn't seem so obvious. Of course we have to ask what an "ape" is. While I realize that Hominoidea species not (too) closely related to the lineage leading to man are frequently called "apes", whether extant or fossil, there seems to be a countervailing tendency to use the term primariliy for modern apes and for a bewildering array of more "ape-like" fossil creatures than those leading to, roughly, ourselves and our closer fossil relatives. It is, to say the least, confusing, but since "ape" has typically been used in contradistinction to ourselves, confusion is likely to be inevitable. Should we not be classified as "apes"? But that is contrary to historical usage of the term. And if we don't call ourselves "apes", then are we to call our ancestors "apes"? Maybe, maybe not. Arguably, we might just call certain specialized primates of the Hominoidea superfamily "apes", while the more generalized species leading to ourselves and our closer relatives are to be called "ape-like" in order to distinguish them from the specialization that has set off apes from ourselves in many minds heretofore. This seems to be the rationale for using the term "ape-like" rather than the more rationalized "ape" term for Hominoidea, and especially for Hominidae. The point being that we may use the terms as we choose, since we in fact are responsible for our terms. Historical, not to mention anthropocentric, reasons tend to make many shy away from calling ourselves and our ancestors "apes". This is what we come up against in language, practically. The language matters, and not the designation "apes", is important to me, since the IDists are fond of using terms like "machines" and "factories" in order to score points among the naive. Taxonomic language is rationalized, and so are terms like "machines" and "factories", within scientific discussion--while "ape", as far as I know, is not. Nor are "machines" and "factories" meant to suggest any sort of analogous origins with the machines and factories we make, they are just functional categories adopted into biology for the sake of convenience.

If not then it sounds like a clade to me. :)

— Henry J
Hominidae, Hominoidea, Homo, and Pan, may be thought of as clades. "Ape", as far as I know, is used ambiguously to refer to Hominoidea species, though often irrationally excluding humans, and also as a distinct name for primates sharing a number of characteristics with each other, some of which are lacking in the Homo genus. It appears that you wish to use "ape" as if it were a clear and defined term, when my point is that it is not that at all. Or if it is, I don't know it. Glen D http://tinyurl.com/b8ykm

Anton Mates · 19 May 2006

Are there any cases of a non-ape species thought to be descended from a species normally called an ape?

— Glen Davidson
Well, yes. I mentioned Australopithecines, and would have mentioned humans if they didn't seem so obvious.

It is, to say the least, confusing, but since "ape" has typically been used in contradistinction to ourselves, confusion is likely to be inevitable. Should we not be classified as "apes"? But that is contrary to historical usage of the term. And if we don't call ourselves "apes", then are we to call our ancestors "apes"? Maybe, maybe not.

Thing is, as far as I'm aware, humans are pretty much always classified as "apes" in modern biology. The last biologist I know offhand who disputed that terminology was Ernst Mayr, and look what happened to him! It's certainly true that "ape" can also be used in contrast to "human" in a more colloquial sense, and plenty of biologists will use it that way. But I don't think that really equates to an assertion that humans aren't apes. By analogy, "human" and "animal" are commonly contrasted ("Is there any animal which uses tools the way humans do?"), and so are "bird" and "reptile." Yet it's not really controversial that humans are animals and that birds are reptiles in a biological sense. (Unless you're Zombie Ernst Mayr, maybe.) And, to go back to the original question, I think it would be accepted that humans are descended from "apes" even in a colloquial sense. Regardless of whether one would prefer our last common ancestors with, say, chimps to be called "ape-like" or "human-like," their last common ancestors with our more distant relatives--orangs, say, or gibbons--would be apes by any definition of the term, wouldn't they? SAMVIT, are you still out there? You may not find this verbal nitpickery all that interesting, but if you do have an example of an inexplicably out-of-place fossil stratum, please do post it. We're just killing time while we wait.

Samvit · 22 May 2006

Hi friends,

Please refer to the 6 th question in the link below and comment.

http://www.parentcompany.com/handy_dandy/hder9.htm

Andrew McClure · 22 May 2006

http://www.parentcompany.com/handy_dandy/hder9.htm

Well, if this is a link-slinging game... #6 at the link you give makes grandiose claims, but only gives two real-world examples of what it is talking about. First, it claims that the fossil and sediment at the Lewis Overthrust are deposited in "reverse order" from what mainstream science would "predict". Second, it claims that pollen has been found inside rocks which date to the precambrian era, which was long before plants which use pollen evolved. Let's see what happens when we look into these claims. When I type "Lewis Overthrust" into Google, I get the link: http://www.talkorigins.org/indexcc/CC/CC341.html And when I probe deeper, I get: http://www.talkorigins.org/faqs/lewis/ These links claim that the layer order in the Lewis Overthrust has been altered by a straightforward geological deformation called a thrust fault, and so in no way conflicts with standard geological or evolutionary theory. These links provide very specific evidence for their arguments, and as far as I can tell they directly address all of the specific claims your links makes as to why we shouldn't consider the Lewis Overthrust to be a thrust fault (if you can't find the bit about the "mixed rock" claim, search in the second link for "rubble or breccia"). Meanwhile, when I type "Precambrian rocks pollen" into Google, I get the link: http://www.talkorigins.org/indexcc/CC/CC341.html This link actually specifically mentions Clifford Burdick-- whom your source uses as its citation on the pollen claim-- and explains why the rocks he analyzed are much better explained as examples of modern pollen contaminating an older rock, rather than an older rock which contained pollen to begin with. #6 at your link also references a magazine article from 1985 which it claims contains examples of "hundreds of such reversals". Considering it only took a few seconds to find detailed responses to the two claims your link incorporates directly, I don't have high hopes for the contents of this article, whereever it is. (Bonus trivia: Mr. Lammerts who wrote this article gets a brief mention in one of the links I pulled off Google above.)

Anton Mates · 26 May 2006

These links claim that the layer order in the Lewis Overthrust has been altered by a straightforward geological deformation called a thrust fault, and so in no way conflicts with standard geological or evolutionary theory. These links provide very specific evidence for their arguments, and as far as I can tell they directly address all of the specific claims your links makes as to why we shouldn't consider the Lewis Overthrust to be a thrust fault (if you can't find the bit about the "mixed rock" claim, search in the second link for "rubble or breccia").

— Andrew McClure
Rather a nice bit of irony there, in that the very "shale" SAMVIT's source finds so impressive is likely to be the erosional "mixed rock" he complains is absent.