Tiktaalik: Data vs. Assumptions

[Jimmy D]

“Tiktaalik lacks a sacral rib connecting the pelvic girdle with the vertebral column”

You accidentally missed the second half of the sentence...

"the iliac blade is relatively more massive and dorsally expanded than in fish; indeed, it rises minimally to the level of the vertebral column".

Maybe it is a new development then? Not quite like it's fishy ancestors, not quite like later land based tetrapods. You could almost say transitional between the two?

In the abstract these very scientists admit that “the pelvic fin was not capable of bearing stresses and strains as significant as those of Acanthostega and Ichthyostega, nor was the musculature as well-developed for appendage retraction.”

Are they "admitting" something or explaining why the pelvic fin represents a transitional stage? I mean, it actually says....

"Plesiomorphic features of Tiktaalik can be interpreted as highlighting a functional difference with limbed forms: the pelvic fin was not capable of bearing stresses and strains as significant as those of Acanthostega and Ichthyostega....."

So what they are not telling us is that this means it COULD NOT walk on land for any significant length of time. Since we do not assume Icthy walked on land, and these features in Tik are not even as capable as in Ichthy, then WHY should we assume Tik did so?

Burn the strawman!

And yes I know Shubin and his team did not claim that Tik was a landwalker, but so many others on discussion forums like these envision that very thing in their minds.

I see, you're arguing against what you think we might incorrectly envision in our minds. Thanks for that.

Talk about a leap of faith...wrong architecture, not connected in necessary ways, similar to other earlier non-landwalking FISH, and yet????

Similar but distinct to non-landwalking fish, similar but distinct to later tetrapods... and yet????

If it's too similar to "non-landwalking fish" to satisfy you as a transitional species how about Acanthostega, does that meet your requirements? Or is it too far away from a "non-landwalking fish" to be transitional?

 

[Ophiolite]

Great! Now go back to the subject of Tiktaalik...

In analyzing the pelvic girdle found, we do not see a new development on the way to becoming a land walking tetrapod at all. Shubin himself admits the architecture of the bones are pleisomorphic therefore similar to earlier ancestors, and despite the constant re-emphasis of the story line, he also admits that “Tiktaalik lacks a sacral rib connecting the pelvic girdle with the vertebral column” which is a necessary factor in land walking tetrapods. See Shubin, N.H., Daeschler, E.B., and Jenkins, F.A. Jr., Pelvic girdle and fin of Tiktaalik roseae, PNAS 111(3):893–899, 21 January 2014 | doi:10.1073/pnas.1322559111

In the abstract these very scientists admit that “the pelvic fin was not capable of bearing stresses and strains as significant as those of Acanthostega and Ichthyostega, nor was the musculature as well-developed for appendage retraction.”

So what they are not telling us is that this means it COULD NOT walk on land for any significant length of time. Since we do not assume Icthy walked on land, and these features in Tik are not even as capable as in Ichthy, then WHY should we assume Tik did so?

And yes I know Shubin and his team did not claim that Tik was a landwalker, but so many others on discussion forums like these envision that very thing in their minds. Talk about a leap of faith...wrong architecture, not connected in necessary ways, similar to other earlier non-landwalking FISH, and yet????

I have four issues with your post

1. Misleading use of rhetoric.
2. False statement regarding content of the abstract.
3. Misrepresentation of Shubin's position.
4. Contradictory views on the significance of specimen preservation

Misleading use of rhetoric
In post #31 you stated "A five year study on propaganda and brainwashing opened my mind to lot of these techniques."
It seems the five years was not wasted. In your short post you used emotive words to falsely characterise actions/observations/comments by the paper's authors. Namely:

• Shubin himself admits
• despite the constant re-emphasis of the story line, he also admits
• In the abstract these very scientists admit

The word "admits" implies, perhaps even requires, a guilty action recognised by the person admitting guilt. Your use of these words appears designed to cast doubt on the integrity of the paper's authors.
"Very" and "story line" are less troublesome, but still contain subtle elements suggesting shennanigans of one sort or another.

False Statement Regarding the Abstract
You state the following:
"In the abstract these very scientists admit that “the pelvic fin was not capable of bearing stresses and strains as significant as those of Acanthostega and Ichthyostega, nor was the musculature as well-developed for appendage retraction.” "

Here is the abstract:

A major challenge in understanding the origin of terrestrial vertebrates has been knowledge of the pelvis and hind appendage of their closest fish relatives. The pelvic girdle and appendage of tetrapods is dramatically larger and more robust than that of fish and contains a number of structures that provide greater musculoskeletal support for posture and locomotion. The discovery of pelvic material of the finned elpistostegalian, Tiktaalik roseae , bridges some of these differences. Multiple isolated pelves have been recovered, each of which has been prepared in three dimensions. Likewise, a complete pelvis and partial pelvic fin have been recovered in association with the type specimen. The pelves of Tiktaalik are paired and have broad iliac processes, flat and elongate pubes, and acetabulae that form a deep socket rimmed by a robust lip of bone. The pelvis is greatly enlarged relative to other finned tetrapodomorphs. Despite the enlargement and robusticity of the pelvis of Tiktaalik , it retains primitive features such as the lack of both an attachment for the sacral rib and an ischium. The pelvic fin of Tiktaalik (NUFV 108) is represented by fin rays and three endochondral elements: other elements are not preserved. The mosaic of primitive and derived features in Tiktaalik reveals that the enhancement of the pelvic appendage of tetrapods and, indeed, a trend toward hind limb-based propulsion have antecedents in the fins of their closest relatives.

Note that your quoted words do not appear. For the last couple of years, in addition to the Abstract, PNAS papers have included a summary paragraph or two on the Signficance of the paper. I considered that you may have lifted the statement from there and inadvertently identified it as being from the abstract. The words are not there either.

I am reasonably sure they can be found elsewhere in the paper, but my issue is this. If you make errors of this nature it calls into question everything you post here. That makes addressing your posts tiresome, since before one can get to the beef, one has to check whether or not there is any horse meat present. (Metaphor for the amusement of UK residents and Anglophiles.)

Misrepresentation of Shubin's Conclusions
Your post states that certain of Shubin's observations reveal a flawed and incoherent conclusion, whereas, in total, the observations lead to the conclusion stated in the last paragraph of the Abstract, quoted above.

Contradictory views on the significance of specimen preservation
You expressed strong reservations, at least once, about the condition of the specimens. Here are your words:
"Using only what is actually there (badly crushed) it is almost impossible to say anything about the body except very general information . . "

Hereis the conflict. The statement above is clear and yet in this paper the authors note that "Multiple isolated pelves have been recovered, each of which has been prepared in three dimensions".

It is from these that the authors have been able to make the detailed observations you have used to challenge the significance of Tikaalik. Yet it is "almost impossible to say anything about the body".

So, either you still maintain that position, in which case your objections here are groundless, since that observations could not have been extracted. Or, you concede that in the light of techniques to restore original form, or as a consequence of multiple specimens, your original objection no longer stands.

I don't think that is a false dichotomy, but if I missed an option do let us know. Otherwise, which explantion is the correct one. (I hope it means you have changed your mind on one point at least. It would hold out a glimmer of hope.)

 

[tas8831]

"I see your question begging here. artistic reconstructions are nice to look at, but surely you don't think those are presented as evidence, do you?"

No! But image imprinting is a common technique used to convince students and the gullible masses (one picture is worth 1000 words).

Like all those pictures of a blue-eyed, fair-skinned Jesus?

Or like when someone doctored a quote to make it appear as though Blum claimed something was "impossible" when he hadn't actually written that?

When such images in texts and presentations (sadly even on PBS documentaries) are planted over and over through the years the image sticks as if it is an established and accepted understanding. It is a form of conditioning by association that is unnecessary in the presentation of evidentially based truth.

Right, OK.

But they are not presented as evidence, you agree?

 

[tas8831]

What an utter waste of time.

Responding substantively to your biased, naive ranting?

Yes, i know, but I tried.

I also have read Shubin's papers with excitement but that does not change the facts.

No, it doesn't. But it also demonstrates that you appear to have ignore many facts that do not fit your presupposed anti-evolution conclusions.

Clearly some things CAN BE interpreted according to this belief system through the lens of the presupposed conclusions. Who knows perhaps Tik could breathe through his skin for a time (like mudskippers)..could be...

Ah so your could be and perhaps are totally cool, but you have no evidence - but when there IS evidence, you dismiss it if it does conform to your presupposed anti-evolution conclusions.

Got it.

The crushed chest area is NOT robust

What an amazing 'opinion' premised on wishful interpretation!

Look at the trunk region of an actual fish, then look at the trunk region of Tik - one has to willfully ignore the thickness of the ribs to proclaim their lack of robustness!

Writing something as if it were a foregone conclusion when it is really just your desire does not make others believe it, by the way.

and the rib bones do not equal a cavity for lungs (though they COULD HAVE been so)

So you are claiming - with zero knowledge, zero relevant expertise or experience, that there was no thoracic cavity in this creature?

You know, even fish have a body cavity. But their ribs are not robust at all, since they are not needed for breathing.

Thanks for replying pretty much how I expected.

All of your "evidence" for assumptions (as opposed to data) were just your own presuppositions.

 

[tas8831]

“Tiktaalik lacks a sacral rib connecting the pelvic girdle with the vertebral column” which is a necessary factor in land walking tetrapods.

1. evidence please
2. I don't think anyone has claimed that Tik was scampering about on land - in fact, the artistic renditions that you hate with such passions indicate Tik crawling along the water's edge, almost dragging its back half around.
3. and why base your 'argument' on these strawmen whan you have admitted that "And yes I know Shubin and his team did not claim that Tik was a landwalker"?

http://pbs.bento.storage.s3.amazona...text-pages/yif_ep 2 _04_tiktaalik_aboutov.jpg


Not galloping around like a Gorgon or something.


Creationists just love to embellish things - I had mentioned Menton (YEC anatomist) because as you imply for the pelvic region, Menton had declared that Tik lacked a bone-to-bone connection between the shoulder girdle and axial skeleton, and that this is REQUIRED for moving on land.

Menton the creationist anatomist, however, had not done his homework (or was lying to the masses, or was hoping his creationist audience wouldn't know any better or care) - for there are entire groups of terrestrial tetrapods that lack such an attachment, including, amazingly, Elephants.

Menton didn't mention that, though. Spoiled his 'assumption'-based creationist tales.

So please - let us all know where you got such assumptions.


And isn't it just an amazing coincidence that you honed in on and drew almost identical 'conclusions' as did some fellow named Nunn at creation.com:

Already certain of Tiktaalik’s place in the evolutionary story, Shubin and friends decree:

“Antecedents of canonical tetrapod pelvic characteristics are seen in Tiktaalik. Although Tiktaalik lacks a sacral rib connecting the pelvic girdle with the vertebral column, the iliac blade is relatively more massive and dorsally expanded than in fish.”10
This sounds hopeful, except that the lack of a sacral rib connecting the pelvic girdle to the vertebral column is integral for tetrapods to be able to bear their weight on land!​

Amazing how frequently your 'arguments' are just so much like so many other folks' on creationist websites...

 

[pshun2404]

Soooooo... conspiracy?

Not at all! Though WAY off topic, those politicians and ad men and public relations teams use these techniques as part of their regular business (convincing people, selling their idea or product, impressing the masses with a questionable premise, and so on). They do it intentionally and professionally (and deceit is often part of what occurs) and all popularized media employ such people (because it is all about selling their product).

Now if at any time all these people or groups had gotten together (in secret or in public) and made a decision as a group to perpetrate the fallacy (say "one on every ten dentists recommend Crest") then it is a conspiracy in that they conspired to do this to produce the desired effect. It is a known fact that in published articles and articles as presented in popular media (in science these would be like National Geographic or Smithsonian and even on occasion in Peer reviewed Journals) that scientists fail to report questionable possibility or even re-phrase to only include supportive statements and even exclude information or data regarding contrary perspectives.

The other issue however is that if an INDIVIDUAL is unwavingly CONVINCED of one only perspective (say a Ken Ham or a Richard Dawkins), or has a motive in perpetuating only that viewpoint, then that individual will interpret everything through that lens. "Conspiracy theory", which is what you are trying to imply I am saying here, is not even close.

Now what do you have to contribute to the discussion about Tiktaalik?

 

[tas8831]

A five year study on propaganda and brainwashing opened my mind to lot of these techniques.

Which 5 year study was that?

 

[tas8831]

The reconstructions sadly do not really demonstrate what the creature looked like or demonstrate Tik breathed in any other way but through gills (and more). But thanks...

Incredible.

It is as if you think that the people doing the reconstructions have no idea what they are doing.

 

[tas8831]

I object to your characterisation of my post as pseudo-hominem on two grounds:

First, the pedant in me suggests that you meant pseudo-ad hominem.

Secondly, in attacking the quality of your argument I was implicitly and unavoidably attacking your own qualities. Consequently the adjective "pseudo" is not applicable.

Plus, attacking the quality of the argument is NOT an irrelevant characteristic and is this not really an ad hominem.

I also don't think bringing up a person's past antics in forum posts is irrelevant - embellishing one's credentials, creating an appeal to one's own supposed authority, plagiarizing, doctoring quotes - these are NOT irrelevant. One's appearance, affiliations, etc. - those are irrelevant.

 

[tas8831]

...wrong architecture, not connected in necessary ways, similar to other earlier non-landwalking FISH, and yet????

Talk about strawmen!

 

[tas8831]

duplicate

 

[tas8831]

I've been reading creationist website takes on Tiktaalik (thanks, pshun!) and I have caught a professional creationist in a lie (imagine that!) -

Medical doctor Elizabeth Mitchell writes in a caption of a Tiktaalik artistic rendition (note the bolding and/or italics I added for emphasis in both quotes):

In fact, the evolutionary imagination accords this fish’s hind-parts so much power, they believe it was ready for “pelvic-propelled locomotion”1 across the terrestrial world and up the evolutionary tree.​

The 1 links to this article:

N. Shubin et al., “Pelvic girdle and fin of Tiktaalik roseae,” Proceedings of the National Academy of Sciences (13 January 2014)


wherein one finds this passage - the only passage in which one finds the word "propelled":

Tiktaalik reveals that features contributing to the trend toward pelvic-propelled locomotion in the tetrapodomorph stem began emerging in finned taxa before being enhanced in more derived digited forms. Indeed, this trend has deep roots or parallel trajectories: diverse lungfish, both fossil
and extant, have pectoral and pelvic girdles that are subequal in size (17).​

Why do professional creationists lie like this? Is it because they have brainwashed their target audiences (with the help or evangelical fundamentalists) into bowing to their perceived authority so it doesn't matter?

Or are most of them just incompetent and don't know any better?

Pshun - in the 5 year study on propaganda and brainwashing you mention, does it cover the lies told by perceived authorities?

 

[tas8831]

Are they "admitting" something or explaining why the pelvic fin represents a transitional stage? I mean, it actually says....

"Plesiomorphic features of Tiktaalik can be interpreted as highlighting a functional difference with limbed forms: the pelvic fin was not capable of bearing stresses and strains as significant as those of Acanthostega and Ichthyostega....."

Burn the strawman!

I see, you're arguing against what you think we might incorrectly envision in our minds. Thanks for that.



Similar but distinct to non-landwalking fish, similar but distinct to later tetrapods... and yet????

If it's too similar to "non-landwalking fish" to satisfy you as a transitional species how about Acanthostega, does that meet your requirements? Or is it too far away from a "non-landwalking fish" to be transitional?

Looks like pshun read that amazing 5 year study on brainwashing to get tips...

 

[pshun2404]

The crushed chest area is NOT robust

What an amazing 'opinion' premised on wishful interpretation! Look at the trunk region of an actual fish, then look at the trunk region of Tik - one has to willfully ignore the thickness of the ribs to proclaim their lack of robustness!

The creature is very large so the rib bones will also be larger but if the rib cage has been thoroughly crushed and flattened its purpose and shape is now misshaped beyond compare. The “crushed chest” is not robust.


and the rib bones do not equal a cavity for lungs (though they COULD HAVE been so)

So you are claiming - with zero knowledge, zero relevant expertise or experience, that there was no thoracic cavity in this creature?


Re-read the sentence you quote. I made no such absurd claim. Nothing in the fossil suggests lungs but all fish of course have a thoracic cavity (it’s what might have been in it that is in question here). Though I admit it could have had this purpose we simply cannot know.


You know, even fish have a body cavity. But their ribs are not robust at all, since they are not needed for breathing.

Robustness does not equal being for breathing...

I don't think anyone has claimed that Tik was scampering about on land - in fact, the artistic renditions that you hate with such passions indicate Tik crawling along the water's edge, almost dragging its back half around.

a) I made the point that these scientists were not saying that.

b) I do not hate any of the artistic contrivances I just understand their purpose.

Menton had declared that Tik lacked a bone-to-bone connection between the shoulder girdle and axial skeleton, and that this is REQUIRED for moving on land.

a) I never mentioned Menton and have never read anything written by Menton. If you asked me to name something he has written I literally would have to google it.

b) the fossil showed a separation though I never implied this was the normal condition of the actual creature when it was alive (of course I also assume when it was alive 370 mya it was connected)

c) even if and when connected, it was not a creature that could survive out of the water for any significant length of time (and no scientist that worked on the fossils makes that claim) but rather that it was “transitional” between fish and land walking tetrapods.

Also, Elephants shoulder bones are indeed connected to its skeleton (or it would fall to the ground) though they are not being discussed here, and all the references to the pelvis came from the PNAS article (who the hell is Nunn? Please do not tell me I do not care.)

 

[pshun2404]

You accidentally missed the second half of the sentence...

"the iliac blade is relatively more massive and dorsally expanded than in fish; indeed, it rises minimally to the level of the vertebral column".

Maybe it is a new development then? Not quite like it's fishy ancestors, not quite like later land based tetrapods. You could almost say transitional between the two?



Are they "admitting" something or explaining why the pelvic fin represents a transitional stage? I mean, it actually says....

"Plesiomorphic features of Tiktaalik can be interpreted as highlighting a functional difference with limbed forms: the pelvic fin was not capable of bearing stresses and strains as significant as those of Acanthostega and Ichthyostega....."

Burn the strawman!

I see, you're arguing against what you think we might incorrectly envision in our minds. Thanks for that.

Similar but distinct to non-landwalking fish, similar but distinct to later tetrapods... and yet????

If it's too similar to "non-landwalking fish" to satisfy you as a transitional species how about Acanthostega, does that meet your requirements? Or is it too far away from a "non-landwalking fish" to be transitional?

Great post Jim, thanks...real content. Refreshing except for the alleged strawman comment.

Maybe it is a new development then?

Maybe?

And yes also similar but distinct from land walking tetrapods that had already existed for millions of years!

 

[pshun2404]

Which 5 year study was that?

My own! I wanted to find out techniques and strategies used to convince people so I could learn to oppose and re-program negative attitudes, beliefs, and stereotypes. It began when our class was challenged by Dr. Walter Mott (a sociology professor) to explore what we were convinced of to determine if we were basing them on personal experience, what we were taught, the need to fit in, and so on, after revealing how so much misinformation fills history books. This inspired me to delve much much deeper (I will ever be so grateful).

 

[pshun2404]

Looks like pshun read that amazing 5 year study on brainwashing to get tips...

Consumed many works of many people and read many many studies for information...(Berneys, James, Geobbels, and many many more)

 

[pshun2404]

I've been reading creationist website takes on Tiktaalik (thanks, pshun!) and I have caught a professional creationist in a lie (imagine that!) -

Medical doctor Elizabeth Mitchell writes in a caption of a Tiktaalik artistic rendition (note the bolding and/or italics I added for emphasis in both quotes):

In fact, the evolutionary imagination accords this fish’s hind-parts so much power, they believe it was ready for “pelvic-propelled locomotion”1 across the terrestrial world and up the evolutionary tree.​

The 1 links to this article:

N. Shubin et al., “Pelvic girdle and fin of Tiktaalik roseae,” Proceedings of the National Academy of Sciences (13 January 2014)

wherein one finds this passage - the only passage in which one finds the word "propelled":

Tiktaalik reveals that features contributing to the trend toward pelvic-propelled locomotion in the tetrapodomorph stem began emerging in finned taxa before being enhanced in more derived digited forms. Indeed, this trend has deep roots or parallel trajectories: diverse lungfish, both fossil
and extant, have pectoral and pelvic girdles that are subequal in size (17).​

Why do professional creationists lie like this? Is it because they have brainwashed their target audiences (with the help or evangelical fundamentalists) into bowing to their perceived authority so it doesn't matter?

Or are most of them just incompetent and don't know any better?

Pshun - in the 5 year study on propaganda and brainwashing you mention, does it cover the lies told by perceived authorities?

Finally actually a good point thanks. YES YES YES many creationists also do the exact same thing. YES many of them try to "convince" their target audience by interpreting the evidence though their lens (the presupposed belief they want everyone to accept and believe).

 

[pshun2404]

TAS

Admits does not have to imply this guilt you are implying that I implied (which I did not). To admit means to concede, acknowledge, state, confess and so on.

Pelvic girdle and fin of Tiktaalik roseae

In the discussion section (my bad, it was not the abstract) Shubin writes

“Plesiomorphic features of Tiktaalik can be interpreted as highlighting a functional difference with limbed forms: the pelvic fin was not capable of bearing stresses and strains as significant as those of Acanthostega and Ichthyostega, nor was the musculature as well-developed for appendage retraction.”

I stand corrected as to the location in the article.

 

[tas8831]

The crushed chest area is NOT robust

What an amazing 'opinion' premised on wishful interpretation! Look at the trunk region of an actual fish, then look at the trunk region of Tik - one has to willfully ignore the thickness of the ribs to proclaim their lack of robustness!

The creature is very large

Very large?


Here is a bluefin tuna skeleton. They get to be about 800 pounds, 13 feet long.

Please look at its ribs.

And then ask yourself why you write the things you do.

and the rib bones do not equal a cavity for lungs (though they COULD HAVE been so)

So you are claiming - with zero knowledge, zero relevant expertise or experience, that there was no thoracic cavity in this creature?


Re-read the sentence you quote. I made no such absurd claim.

I saw what you wrote. " rib bones do not equal a cavity for lungs"

Nothing in the fossil suggests lungs

According to you, with your obvious top-notch background in anatomy, physiology, and paleontology.

You know, even fish have a body cavity. But their ribs are not robust at all, since they are not needed for breathing.

Robustness does not equal being for breathing...

According to you, with your obvious top-notch background in anatomy, physiology, and paleontology.

Look at the tuna skeleton again.

I don't think anyone has claimed that Tik was scampering about on land - in fact, the artistic renditions that you hate with such passions indicate Tik crawling along the water's edge, almost dragging its back half around.

a) I made the point that these scientists were not saying that.

Then why is that notion one of your main lines of "argument"?

Show us even the most naive of pro-science poster's on this or any other forum implying what you claim.

b) I do not hate any of the artistic contrivances I just understand their purpose.

Right - you think it is propaganda/brainwashing.

What do you think of the frequent requirement in venues like Vacation Bible school to memorize and be able to recite bible verses?

Menton had declared that Tik lacked a bone-to-bone connection between the shoulder girdle and axial skeleton, and that this is REQUIRED for moving on land.

a) I never mentioned Menton and have never read anything written by Menton. If you asked me to name something he has written I literally would have to google it.

Funny, I explicitly indicated that I had mentioned Menton:

"Creationists just love to embellish things - I had mentioned Menton (YEC anatomist) ..."


- but you left that out. Part of your propaganda technique, I suppose.

b) the fossil showed a separation though I never implied this was the normal condition of the actual creature when it was alive (of course I also assume when it was alive 370 mya it was connected)

Then why did you bring it up?

c) even if and when connected, it was not a creature that could survive out of the water for any significant length of time (and no scientist that worked on the fossils makes that claim)

So why bring it up?

but rather that it was “transitional” between fish and land walking tetrapods.

So, you admit that now?

Also, Elephants shoulder bones are indeed connected to its skeleton (or it would fall to the ground)

LOL!

My gosh...

You people do not know when to stop.

African Elephant Loxodonta africana - Detailed Anatomy Notes (Literature Reports)

http://www.walkdinosaur.com/pic/other/2015-11-30-02-51-586.jpg

And the artiodactyls (pigs, deer, bison, etc.) - also, no clavicles.


Please just stop.

though they are not being discussed here, and all the references to the pelvis came from the PNAS article

Well, except for the parts you coincidentally (propagandistically?) left out...