[_ Old Earth _] New mammalian transitional adds information on reptile-mammal evolutionNature 472, 181–185 (14 April

[Barbarian]

Well, a couple of years ago, but one more predicted transitional found.

Nature 472, 181–185 (14 April 2011) | doi:10.1038/nature09921

Transitional mammalian middle ear from a new Cretaceous Jehol eutriconodont

Jin Meng , Yuanqing Wang & Chuankui Li

Abstract
The transference of post-dentary jaw elements to the cranium of mammals as auditory ossicles is one of the central topics in evolutionary biology of vertebrates. Homologies of these bones among jawed vertebrates have long been demonstrated by developmental studies; but fossils illuminating this critical transference are sparse and often ambiguous. Here we report the first unambiguous ectotympanic (angular), malleus (articular and prearticular) and incus (quadrate) of an Early Cretaceous eutriconodont mammal from the Jehol Biota, Liaoning, China. The ectotympanic and malleus have lost their direct contact with the dentary bone but still connect the ossified Meckel|[rsquo]|s cartilage (OMC); we hypothesize that the OMC serves as a stabilizing mechanism bridging the dentary and the detached ossicles during mammalian evolution. This transitional mammalian middle ear narrows the morphological gap between the mandibular middle ear in basal mammaliaforms and the definitive mammalian middle ear (DMME) of extant mammals; it reveals complex changes contributing to the detachment of ear ossicles during mammalian evolution.

 

[Asyncritus]

Ah, Barbarian, Barbarian, Barbarian!

You still pin your hopes on chinese fossils, do you? Most unwise, most unwise.

Anyway, here's Dr Gish's commentary on the subject in the article you quoted, despite your own stricture disallowing quotations.

The Reptilian vs. the Mammalian Ear

Furthermore, we cannot divorce the evidence related to the jaw-joint from that related to the auditory apparatus. As mentioned earlier, evolutionists believe that as the bones in the reptilian jaw, except for the dentary, gradually became relieved of their function in the jaw they were now free either to evolve out of existence or to assume some new function. Thus, the quadrate and articular bones of the jaw became free (they were, by the way, firmly attached to the dentary in Morganucodon) and somehow worked their way into the middle ear to eventually become the incus and malleus, respectively.

Now the anatomical problems associated with such a postulated process are vastly greater than merely imagining how two bones precisely shaped to perform in a powerfully effective jaw-joint could detach themselves, force their way into the middle ear, reshape themselves into the malleus and incus, which are precisely engineered to function with a remodeled stapes in a vastly different auditory apparatus, while all at the same time the creature continues to chew and to hear!

As insuperable as this problem appears to be, it pales into relative insignificance when we consider the fact that the essential organ of hearing in the mammal is the organ of Corti, an organ not possessed by a single reptile, nor is there any evidence that would provide even a hint of where this organ came from.

The organ of Corti is an extremely complicated organ. It is suggested that the reader consult one of the standard texts on anatomy for a description. One cannot help but marvel at this complex and wondrously designed organ. It has no homologue in reptiles. There is no possible structure in the reptile from which it could have been derived. It would have had to have been created de novo, since it was entirely new and novel.

According to evolution theory, all evolutionary changes occur as the result of mistakes during the reproduction of genes. These are called mutations, and each change brought about by such mutations which survived must have been superior to preceding forms. Thus, if evolution is true, we must believe that a series of thousands and thousands of mistakes in a marvelously coordinated fashion gradually created the organ of Corti to function in an ear which at the same time had to be reeingineered accordingly while dragging in two bones from the jaw which had to be redesigned.

Furthermore, each intermediate stage not only had to be fully functional but actually must have been superior to the preceding stage. And after all this was accomplished, we still have reptiles and birds today with the same old-fashioned reptilian auditory apparatus which is just as efficient as the corresponding mammalian apparatus.

Other Required Changes

Furthermore, while all of the above miraculous changes were occurring, these creatures also invented (by genetic mistakes) many other marvelous new physiological and anatomical organs and processes, including a new mode of reproduction, mammary glands, temperature regulation, hair, and a new way of breathing.

The structure of the thoracic girdle of the mammal differs fundamentally from that of the reptile. In the reptile it articulates with the breastbone by means of the coracoid bones and forms part of the thorax. This is not the case with mammals.

In reptiles the fore part of the thorax is rigid and incapable of expansion.

In mammals the thorax is expansible. In mammals the thoracic and abdominal cavities are partitioned by the diaphragm, a fibro-muscular organ.

Since reptiles have no diaphragm, their thorax is not a closed box. As a consequence of the above, reptiles cannot breathe as mammals do. They cannot alternately expand and contract the thorax as is the case with mammals. They must breathe buccally.

There is no structure in a reptile that is in any way similar or homologous to the mammalian diaphragm. There is no structure found in a reptile from which it could have been derived.

Again, a complicated structure had to be created de novo (and by mistake!) to perform a function that was already being very satisfactorily performed in a different manner in the assumed reptilian ancestor.

Summary

Whatever one chooses to call them, Morganucodon and Kuehneotherium possessed the full complement of reptilian bones in the jaw, a powerful, fully-functional reptilian jaw-joint and the standard single-bone reptilian ear.

On the other hand, all mammals, living or fossil, have a single jawbone, a fully developed mammalian jaw-joint, and a vastly different auditory apparatus involving three bones in the middle ear and a totally unique and extremely complex structure, the organ of Corti.

As described briefly above, there are many other fundamental differences between reptiles and mammals. It is argued here that these changes could not possibly have occurred gradually, and thus the notion that a reptile gradually evolved into a mammal is scientifically unacceptable.

That says it very well, I think.

Comments, please. No personalities are allowed.

 

[Barbarian]

Anyway, here's Dr Gish's commentary

The same "Dr. Gish" who had this comment?

"But, on the other hand, if you look at certain proteins, you will find that man is more closely related to a bullfrog than he is to a chimpanzee."

In spite of repeated requests, including some from his fellow creationists, Gish never produced any evidence for that wild claim. The follow-up has some relevance to this discussion:

Of course, Gish refused to defend Flood Geology (as he always does), launched into his usual description of the reptile-mammal transition requiring the jaw to unhinge and then much later hinge itself again so that the mammal-like reptiles couldn't "chew and hear at the same time" (which Kitcher countered by citing the many Jurassic mammals with "reptilian" jaws and the transitional forms with double jaw joints; this was obviously lost on Gish, but not on the audience)

In his final remarks, Kitcher demanded that Gish either produce references for the chicken and bullfrog proteins or admit that they do not exist. Gish ignored the challenge, which apparently disappointed many in the audience who had read my editorial, for Gish's final remarks were punctuated with sporadic cries of 'Bullfrog!'
http://cre-ev.dwise1.net/bullfrog.html
Let's see what he has to say, this time...

"As mentioned earlier, evolutionists believe that as the bones in the reptilian jaw, except for the dentary, gradually became relieved of their function in the jaw they were now free either to evolve out of existence or to assume some new function. "

Gish is apparently unaware that those bones connect to the middle ear, even though they are attached to the lower jaw.

,

Surprise.

Gish continues:
"Thus, the quadrate and articular bones of the jaw became free (they were, by the way, firmly attached to the dentary in Morganucodon) and somehow worked their way into the middle ear to eventually become the incus and malleus, respectively."

Those bones didn't gain "some new function." They always served as a way of conducting vibrations to the inner ear. It was their primary function.

"Now the anatomical problems associated with such a postulated process are vastly greater than merely imagining how two bones precisely shaped to perform in a powerfully effective jaw-joint could detach themselves, force their way into the middle ear, reshape themselves into the malleus and incus, which are precisely engineered to function with a remodeled stapes in a vastly different auditory apparatus, while all at the same time the creature continues to chew and to hear! "

All that happened was that the bones became gradually smaller, (as documented in the fossil record), the dentary formed a new jaw joint (before the old one disappeared), and the smaller bones eventually lost their connection to the dentary as Meckel's ossified cartilage became smaller.

In humans, the cartilaginous bar of the mandibular arch is formed by what are known as Meckel’s cartilages (right and left) also known as Meckelian cartilages; above this the incus and malleus are developed.


The dorsal end of each cartilage is connected with the ear-capsule and is ossified to form the malleus; the ventral ends meet each other in the region of the symphysis menti, and are usually regarded as undergoing ossification to form that portion of the mandible which contains the incisor teeth.


The intervening part of the cartilage disappears; the portion immediately adjacent to the malleus is replaced by fibrous membrane, which constitutes the sphenomandibular ligament, while from the connective tissue covering the remainder of the cartilage the greater part of the mandible is ossified.
http://en.wikipedia.org/wiki/File:Gray181.png

As you see above, the human embryo has the jawbones in the reptilian form. Only later do the articular and quadrate bones lose their connection to Meckel's cartilage, and become the incus and malleus of the adult mammal. So much for that.

"As insuperable as this problem appears to be, it pales into relative insignificance when we consider the fact that the essential organ of hearing in the mammal is the organ of Corti, an organ not possessed by a single reptile, nor is there any evidence that would provide even a hint of where this organ came from... It would have had to have been created de novo, since it was entirely new and novel."

Apparently, Gish is completely unaware that reptiles have a similar organ, the capsule of basilar papilla, which arises from the same tissues and functions the same way that the Organ of Corti does. Tiny "hair cells" respond to specific frequencies, to generate signals to the brain of reptiles.
http://link.springer.com/article/10.1007/BF01104034#page-1

 

[Barbarian]

Next, Gish completely forgets about natural selection:

"According to evolution theory, all evolutionary changes occur as the result of mistakes during the reproduction of genes. These are called mutations, and each change brought about by such mutations which survived must have been superior to preceding forms. Thus, if evolution is true, we must believe that a series of thousands and thousands of mistakes in a marvelously coordinated fashion..."

He might not be right, but he's fun to read, isn't he?

"Furthermore, each intermediate stage not only had to be fully functional but actually must have been superior to the preceding stage. "

As indeed, it was. Reducing the size of the quadrate and articular bones made them more sensitive to vibration, and capable of picking up higher frequencies. The single dentary was stronger than the reptilian jaw, and the loss of the old jaw joint made a larger coronoid process, and stronger muscles possible. And since the smaller bones were more sensitive, then there was an advantage in more sensitive basilar papilli. Which is, as you now realize, what happened. Gish, of course, being unaware of the structure, remains completely clueless:

"And after all this was accomplished, we still have reptiles and birds today with the same old-fashioned reptilian auditory apparatus which is just as efficient as the corresponding mammalian apparatus."

It's not remotely as good as mammalian hearing. I don't know about birds, but I suspect Gish messed that up, too. (Barbarian checks) Yep. Turns out, the organ is much more sensitive than in reptiles, and although it also is derived from the same organ in reptiles, it's more complex.

"Furthermore, while all of the above miraculous changes were occurring, these creatures also invented (by genetic mistakes) many other marvelous new physiological and anatomical organs and processes, including a new mode of reproduction,"

Actually, the first mammals laid eggs (some still do).

"mammary glands"

The first mammals almost certainly didn't have them. Monotremes have very simple glands that produce a milk-like substance, that excretes from pores in the skin. This is classic Gish, making it up as he goes along.

"temperature regulation"

In therapsids, from which mammals evolved, their bones have Haversian canals which indicate a warm-blooded animal with a high metabolic output.
http://books.google.com/books?id=pC...onepage&q=therapsids haversian canals&f=false

"The structure of the thoracic girdle of the mammal differs fundamentally from that of the reptile. In the reptile it articulates with the breastbone by means of the coracoid bones and forms part of the thorax. This is not the case with mammals. "
Hmm..

The platypus has extra bones in the shoulder girdle, including an interclavicle, which is not found in other mammals.
http://www.sheppardsoftware.com/content/animals/animals/mammals/platypus.htm

Let's go on...

"There is no structure in a reptile that is in any way similar or homologous to the mammalian diaphragm.

University of Utah biologists discovered gators maneuver silently by using their diaphragm, pelvic, abdominal and rib muscles to shift their lungs like internal floatation devices: toward the tail when they dive, toward the head when they surface and sideways when they roll.
http://www.unews.utah.edu/old/p/030608-1.html
This is getting monotonous, isn't it?

"Summary
Whatever one chooses to call them, Morganucodon and Kuehneotherium possessed the full complement of reptilian bones in the jaw, a powerful, fully-functional reptilian jaw-joint and the standard single-bone reptilian ear. "
It actually had both a reptilian and a stronger mammalian jaw joint. This story wasn't one of Gish's better efforts.

 

[Barbarian]

Turns out Gish was more than just a little wrong about the thoractic girdle of mammals and reptiles:


Evolution of interclavicle and anterior sternal structure in the cynodont–mammal transition.

From the following article:
Convergent dental adaptations in pseudo-tribosphenic and tribosphenic mammals
Zhe-Xi Luo, Qiang Ji & Chong-Xi Yuan
Nature 450, 93-97(1 November 2007)
doi:10.1038/nature06221

Ornithorhynchus is the platypus. Tachyglossus is the short-beaked echidna. Pseudotribos is a very ancient monotreme. Notice the branch leading off to modern eutherian and metatherian mammals, which lack the reptilian thoractic girdle. So now, the fossil record of monotremes goes back to the time of the dinosaurs.

 

[Asyncritus]

You were specifically asked to refrain from personalities, and much of what you say is really a personality attack and totally irrelevant to the question of the mammalian ear. For example:

· The same "Dr. Gish" who had this comment?

"But, on the other hand, if you look at certain proteins, you will find that man is more closely related to a bullfrog than he is to a chimpanzee."

Let's see what he has to say, this time...

"As mentioned earlier, evolutionists believe that as the bones in the reptilian jaw, except for the dentary, gradually became relieved of their function in the jaw they were now free either to evolve out of existence or to assume some new function. "

Gish is apparently unaware that those bones connect to the middle ear, even though they are attached to the lower jaw.

That is totally incorrect, founded on nothing more than prejudice. Here is a better diagram of comparisons, which entirely support Dr Gish’s comments.

You will note that the dentary is nowhere near the middle ear, the articular is firmly attached to the lower jaw. The quadrate forms no part of the reptilian ear.

The 2 bones are entirely separate and distinct from the reptilian ear

Yet your claim is that they somehow migrated into the ear under the power of the great god, natural selection, which has now been incapacitated by Kimura, Lynch and Kingsolver.

How do you see that happening? And just as important, WHY did it hppen? And how did the poor rept/mamm manage to hear and eat while all this was going on?

 

[Asyncritus]

Gish continues:
"Thus, the quadrate and articular bones of the jaw became free (they were, by the way, firmly attached to the dentary in Morganucodon) and somehow worked their way into the middle ear to eventually become the incus and malleus, respectively."

Those bones didn't gain "some new function." They always served as a way of conducting vibrations to the inner ear. It was their primary function.

This comment is entirely nonsensical.

Look again at the diagram. The dentary is obviously the support for the teeth, and the only vibrations it could convey anywhere were those of its prey being crunched. Nothing whatsoever to do with conducting sound.

Gish is perfectly correct. The quadrate and the articular have nothing to do with hearing either. The name ARTICULAR should have told you this. It is there to assist the ARTICULATION of the lower jaw with the upper.

Gish again:

"The two most distinguishable osteological differences between reptiles and mammals, however, have never been bridged by a transitional series. All mammals, living or fossil, have a single bone, the dentary, on each side of the lower jaw, and all mammals, living or fossil, have three auditory ossicles or ear bones, the malleus, incus and stapes. In some fossil reptiles the number and size of the lower jaw bones are reduced compared to living reptiles.




Every reptile, living or fossil, however, has at least four bones in the lower jaw and only one auditory ossicle, the stapes. . . There are no transitional fossil forms showing, for instance, three or two jawbones, or two ear bones. No one has explained yet, for that matter, how the transitional form would have managed to chew while his jaw was being unhinged and rearticulated, or how he would hear while dragging two of his jaw bones up into his ear." (Gish, 1978, p. 80)

Gish again:

"Now the anatomical problems associated with such a postulated process are vastly greater than merely imagining how two bones precisely shaped to perform in a powerfully effective jaw-joint could detach themselves, force their way into the middle ear, reshape themselves into the malleus and incus, which are precisely engineered to function with a remodeled stapes in a vastly different auditory apparatus, while all at the same time the creature continues to chew and to hear! "

Here’s more of your wishful thinking:

All that happened was that the bones became gradually smaller, (as documented in the fossil record), the dentary formed a new jaw joint (before the old one disappeared), and the smaller bones eventually lost their connection to the dentary as Meckel's ossified cartilage became smaller.

ALL that happened? More magic-wand waving, Barbarian?

Note from the diagram that in the reptile ear, there is a SINGLE bone, the stapes, connecting the eardrum to the inner ear.

In mammals, there are THREE bones, perfectly designed to do their job. Aligned in the correct order, and most importantly, in the correct ratio of sizes. There is nothing chancy here:

The arrangement of the tympanic membrane and ossicles works to efficiently couple the sound from the opening of the ear canal to the cochlea.

There are several simple mechanisms that combine to increase the sound pressure. The first is the "hydraulic principle". The surface area of the tympanic membrane is many times that of the stapes footplate. Sound energy strikes the tympanic membrane and is concentrated to the smaller footplate.

A second mechanism is the "lever principle". The dimensions of the articulating ear ossicles lead to an increase in the force applied to the stapes footplate compared with that applied to the malleus.

A third mechanism channels the sound pressure to one end of the cochlea, and protects the other end from being struck by sound waves. In humans, this is called "round window protection", and will be more fully discussed in the next section.

the ear is so specifically designed that the sound is optimally transmitted due to several effects like, resonance, Impedance Transformation and simple amplification along the ossicles and all these function depend very specifically on the shape and orientation of the various conducting elements of the system. And therefore, even a slight disfigurement might severely impair the conduction of sound.

http://biology.stackexchange.com/questions/10522/difference-in-reptile-inner-ear-and-otosclerosis

There is clearly design, and top-class sound engineering gone on here. All by some chance mutations and the now-defunct ‘natural selection’. Tut, tut, Barbarian!

The bones became smaller, you say – and somehow arranged themselves into the correct order of malleus, incus and stapes! Isn’t that cute?

By chance, these bones, which were essential parts of the jaw articulation mechanism, somehow shifted into the middle ear, and stuck themselves on to the stapes (without the animal going stone deaf, and therefore wiped out by ‘natural selection’)!

What absolute rubbish! Gish is perfectly correct, and you are totally wrong, despite the heavy type in your original quotation!

 

[Asyncritus]

In humans, the cartilaginous bar of the mandibular arch is formed by what are known as Meckel’s cartilages (right and left) also known as Meckelian cartilages; above this the incus and malleus are developed…..http://en.wikipedia.org/wiki/File:Gray181.png

Once again you make the fundamental mistake of telling us what happens now. You don’t tell us – because you can’t – HOW this arrangement and development arose, connecting the reptile and the mammal.

I’m not entirely sure what the purpose of this diagram really is.

The human embryo does not go through the stages of its alleged ancestry. I thought that you knew that Haeckel’s forgeries totally discredited that foolish idea?

Therefore, your nicely drawn diagram is totally irrelevant to this discussion.

As you see above, the human embryo has the jawbones in the reptilian form. Only later do the articular and quadrate bones lose their connection to Meckel's cartilage, and become the incus and malleus of the adult mammal. So much for that.

Utterly irrelevant.

"As insuperable as this problem appears to be, it pales into relative insignificance when we consider the fact that the essential organ of hearing in the mammal is the organ of Corti, an organ not possessed by a single reptile, nor is there any evidence that would provide even a hint of where this organ came from... It would have had to have been created de novo, since it was entirely new and novel."

Apparently, Gish is completely unaware that reptiles have a similar organ, the capsule of basilar papilla, which arises from the same tissues and functions the same way that the Organ of Corti does. Tiny "hair cells" respond to specific frequencies, to generate signals to the brain of reptiles.http://link.springer.com/article/10.1007/BF01104034#page-1

Apparently you are unaware of the fact that there are considerable differences between the reptilian inner ear structure and the mammalian organ of Corti. Here/s wiki:

In most reptiles the perilymphatic duct and lagena are relatively short, and the sensory cells are confined to a small basilar papilla lying between them. However, in birds, mammals, and crocodilians, these structures become much larger and somewhat more complicated. In birds, crocodilians, and monotremes, the ducts are simply extended, together forming an elongated, more or less straight, tube. The endolymphatic duct is wrapped in a simple loop around the lagena, with the basilar membrane lying along one side. The first half of the duct is now referred to as the scala vestibuli, while the second half, which includes the basilar membrane, is called the scala tympani. As a result of this increase in length, the basilar membrane and papilla are both extended, with the latter developing into the organ of Corti, while the lagena is now called the cochlear duct. All of these structures together constitute the cochlea.[10]

In mammals (other than monotremes), the cochlea is extended still further, becoming a coiled structure in order to accommodate its length within the head. The organ of Corti also has a more complex structure in mammals than it does in other amniotes.

How do you suppose the relatively straight reptilian inner ear became the tightly coiled cochlea, which burrows into the bone of the skull on both sides of the head?

No. don’t tell me. Mutations and natural selection! How did I ever guess?

 

[Asyncritus]

Next, Gish completely forgets about natural selection:

And so he should: in fact, so should we all! It is purely and simply inadequate to produce all these amazing effects. Lynch said so.

"According to evolution theory, all evolutionary changes occur as the result of mistakes during the reproduction of genes. These are called mutations, and each change brought about by such mutations which survived must have been superior to preceding forms. Thus, if evolution is true, we must believe that a series of thousands and thousands of mistakes in a marvelously coordinated fashion..."

He might not be right, but he's fun to read, isn't he?

Unfortunately for you and evolution, he is both fun to read and completely right. Just look at that last sentence! Thousands and thousands of mistakes all add up to such a fantastically well engineered and designed structure as the ear (and the eye, and the brain, and the kidney, and the liver ……) Doesn’t that seem a wee bit improbable Barbarian? Doesn’t your conscience whisper in your inner ear that all this is evolutionary bosh?

"Furthermore, each intermediate stage not only had to be fully functional but actually must have been superior to the preceding stage. "

As indeed, it was. Reducing the size of the quadrate and articular bones made them more sensitive to vibration, and capable of picking up higher frequencies. The single dentary was stronger than the reptilian jaw, and the loss of the old jaw joint made a larger coronoid process, and stronger muscles possible. And since the smaller bones were more sensitive, then there was an advantage in more sensitive basilar papilli. Which is, as you now realize, what happened. Gish, of course, being unaware of the structure, remains completely clueless:

You’re simply assuming the case: that all this did happen, and that it progressed from inferior reptilian ear to vastly superior mammalian ear.

That is an ancient and truly valueless debating trick, which has no scientific value whatsoever, and completely fails to even begin to account for the monumental difficulties which stand in the way of a piece or pieces of a reptilian jawbone(s) becoming the exquisitely well designed and engineered middle and inner ear of the mammal.

The concept is pure nonsense, nothing less.

"And after all this was accomplished, we still have reptiles and birds today with the same old-fashioned reptilian auditory apparatus which is just as efficient as the corresponding mammalian apparatus."

It's not remotely as good as mammalian hearing. I don't know about birds, but I suspect Gish messed that up, too. (Barbarian checks) Yep. Turns out, the organ is much more sensitive than in reptiles, and although it also is derived from the same organ in reptiles, it's more complex.

It’s derived from nothing like the reptilian ear. Gish is again perfectly correct, because, as you may have failed to notice, the reptiles are one of the most successful groups of living creatures on the planet. It therefore follows that their hearing isn’t too bad.

 

[Asyncritus]

"Furthermore, while all of the above miraculous changes were occurring, these creatures also invented (by genetic mistakes) many other marvelous new physiological and anatomical organs and processes, including a new mode of reproduction,"

Actually, the first mammals laid eggs (some still do).

Whether they did or did not, doesn’t account for the phenomena Gish mentions.

"mammary glands"

The first mammals almost certainly didn't have them. Monotremes have very simple glands that produce a milk-like substance, that excretes from pores in the skin. This is classic Gish, making it up as he goes along.

What do you mean ‘almost certainly’ didn’t have them? Did they, or didn’t they? Who’s guessing now?

"temperature regulation"
In therapsids, from which mammals evolved, their bones have Haversian canals which indicate a warm-blooded animal with a high metabolic output.http://books.google.com/books?id=pC...onepage&q=therapsids haversian canals&f=false

Mammals did not evolve from therapsids. That’s more wishful thinking, nothing more.

But it is a major physiological step from cold-blooded to warm-blooded creatures.

Why did it take place, and just as important, how did this take place? What were the necessary genetic alterations that were needed before such a change could occur? And why did those highly constructive alterations occur?

And don't forget, evolution cannot answer the question WHY. Because it is brainless, purposeless, and unreasoning.

"The structure of the thoracic girdle of the mammal differs fundamentally from that of the reptile. In the reptile it articulates with the breastbone by means of the coracoid bones and forms part of the thorax. This is not the case with mammals. "Hmm..

The platypus has extra bones in the shoulder girdle, including an interclavicle, which is not found in other mammals.

Great for the platypus – but, as usual, that is not an answer to the question. How does that answer the point being raised?

Let's go on...

 

[Asyncritus]

"There is no structure in a reptile that is in any way similar or homologous to the mammalian diaphragm.

University of Utah biologists discovered gators maneuver silently by using their diaphragm, pelvic, abdominal and rib muscles to shift their lungs like internal floatation devices: toward the tail when they dive, toward the head when they surface and sideways when they roll.http://www.unews.utah.edu/old/p/030608-1.html
This is getting monotonous, isn't it?

And wrong. “Despite lacking a diaphragm muscle, reptiles have a diaphragm-type respiratory system and the act of breathing is accomplished by the reptile moving its throat or rib cage.

http://www.critters360.com/index.php/how-reptiles-breathe-2-27332/

Further:

Structures in fish, amphibians, reptiles, and birds have been called diaphragms, but it has been argued that these structures are not homologous.

For instance, the alligator diaphragmaticus muscle does not insert on the esophagus and does not affect pressure of the lower esophageal sphincter.[5] The lungs are located in the abdominal compartment of amphibians and reptiles, so that contraction of the diaphragm expels air from the lungs rather than drawing it into them.

Do I hear the sound of another train wreck? How did the lungs move from the ABDOMEN into the THORAX of mammals? And WHY did they do so?

Go figure.

 

[Asyncritus]

"Summary
Whatever one chooses to call them, Morganucodon and Kuehneotherium possessed the full complement of reptilian bones in the jaw, a powerful, fully-functional reptilian jaw-joint and the standard single-bone reptilian ear. "

It actually had both a reptilian and a stronger mammalian jaw joint. This story wasn't one of Gish's better efforts.

The evolution of the mammals from the reptiles is another of evolution’s train wrecks, I’m afraid.

 

[Barbarian]

You were specifically asked to refrain from personalities, and much of what you say is really a personality attack and totally irrelevant to the question of the mammalian ear.

You cited Gish as an authority; and with that, you put his credibility on the table. That's how it works. If you'd rather go with evidence instead of quotes, it won't happen.

Example of Gish's competence to discuss biology:
"But, on the other hand, if you look at certain proteins, you will find that man is more closely related to a bullfrog than he is to a chimpanzee."

"As mentioned earlier, evolutionists believe that as the bones in the reptilian jaw, except for the dentary, gradually became relieved of their function in the jaw they were now free either to evolve out of existence or to assume some new function. "
Gish is apparently unaware that those bones connect to the middle ear, even though they are attached to the lower jaw.​

That is totally incorrect, founded on nothing more than prejudice.

No, that's wrong, as you learned earlier. Let's take a look...

,

As you see, the reptilian jaw is connected to the ear, via the quadrate and articular bones. This is why reptiles put their lower jaws to the ground to better pick up sounds.

“The reptilian middle ear connected to the jaw can pick up the ground vibration, whereas the middle ear fully separated from the jaw is certainly much better at receiving the air-borne sound,” said Luo, who collaborated on the study with experts at the University of Nanjing in China.
http://www.cosmosmagazine.com/news/humans-ear-bones-began-reptile-jaws/
We have discussed this before. Gish just didn't realize how it worked.

Here is a better diagram of comparisons, which entirely support Dr Gish’s comments.

(Drawing omitting the articular and quadrate from the middle ear)

You will note that the dentary is nowhere near the middle ear, the articular is firmly attached to the lower jaw. The quadrate forms no part of the reptilian ear.

Your drawing just omits the quadrate and articular when showing the middle ear. As you see in the more accurate drawing I showed you, the two bones are connected to the stapes by connective tissue, just as they are in mammals. If you take a look at the jaw and skull of a reptile, you will see that the quadrate and articular are directly at the middle ear.

Yet your claim is that they somehow migrated into the ear under the power of the great god, natural selection, which has now been incapacitated by Kimura, Lynch and Kingsolver.

See above. They were already there, and being used for hearing. That's what they do in modern reptiles. They didn't migrate as much as they merely became smaller and more sensitive. Meckel's cartilage, which holds them to the lower jaw in reptiles, no longer attaches in mammals or advanced therapsid reptiles. And of course, the "God of natural selection" is also the God of Abraham, and of all creation. He's much better at doing this than you suspect.

As you learned earlier, both Kimura and Lynch agree that natural selection is critical to evolution. On the other hand, if you have some quote (or less likely, evidence) that Lynch or Kimura denied that natural selection sharpened hearing in reptiles, now would be the time to show us.

How do you see that happening?

Pretty much the way it shows in the fossil record, or in the embyrology of mammals. The embryo first has the incus and malleus attached to the jaw and ear, as in reptiles, and only later, Meckel's cartilage retracts, leaving them attached only to the ear.

And just as important, WHY did it happen?

Smaller bones were better able to pick up sounds, and also to get higher frequencies. And the articulation of the dentary made for a stonger lower jaw, and for muscles repositioned to make a more powerful bite. Quite useful for an animal that was now chewing food to bits, rather than merely swallowing, which is more efficient utilization of food.

And how did the poor rept/mamm manage to hear and eat while all this was going on?

As you see, when the second jaw joint formed, there was for a while, both joints. Snakes still have two joints, and they can hear and eat pretty well, Sometimes using one joint, sometimes, the other. And after the incus and malleus were completely free of the jaw, and remained connected only to the middle ear, there wasn't a problem then, either. We have that arrangement.

 

[Barbarian]

Gish gets it wrong, yet again:
"There is no structure in a reptile that is in any way similar or homologous to the mammalian diaphragm.

University of Utah biologists discovered gators maneuver silently by using their diaphragm, pelvic, abdominal and rib muscles to shift their lungs like internal floatation devices: toward the tail when they dive, toward the head when they surface and sideways when they roll.http://www.unews.utah.edu/old/p/030608-1.html

This is getting monotonous, isn't it?​

Structures in fish, amphibians, reptiles, and birds have been called diaphragms, but it has been argued that these structures are not homologous.

For instance, the alligator diaphragmaticus muscle does not insert on the esophagus and does not affect pressure of the lower esophageal sphincter.[5] The lungs are located in the abdominal compartment of amphibians and reptiles, so that contraction of the diaphragm expels air from the lungs rather than drawing it into them.
And yes, Gish was wrong about that also. Similar structures exist in living and fossil organisms.
Also, the therapsid reptile, Thrinaxodon, had the body divided into thoractic and abdominal regions, with the lumbar ribs mere stubs, which would not have allowed a reptilian form of respiration. No organism with that modification has been shown to lack a diaphragm.
http://en.wikipedia.org/wiki/Thrinaxodon#cite_note-5

 

[Barbarian]

There is clearly design, and top-class sound engineering gone on here.

Comes down to evidence. And the evidence, as you learned, shows a gradual reduction in the bones, which did make them more sensitive to sound and to higher-frequency sound. No tinkering required.

All by some chance mutations and the now-defunct ‘natural selection’. Tut, tut, Barbarian!

As you learned, even the guys you cited say that natural selection is critical for evolution. Would you like me to show you that, again?

The bones became smaller, you say – and somehow arranged themselves into the correct order of malleus, incus and stapes!

Since they were already in that order (see the more accurate diagram, which includes all three bones), it's not really that remarkable. Same connections, just smaller.

Isn’t that cute?

God is a lot greater than you thought. His way works.

By chance, these bones, which were essential parts of the jaw articulation mechanism, somehow shifted into the middle ear,

As you see, they were already there.

and stuck themselves on to the stapes

As you see, they were already connected. Just as they are in reptiles, today.

(without the animal going stone deaf, and therefore wiped out by ‘natural selection’)!

That's why it happened that way. You see, reptiles had always had jaws that transmitted vibrations to the middle ear. Still do. So no functional change, there. Just a bit of tuning.

Gish is perfectly correct,

As you now see, Gish had the anatomy and the function of these structures completely wrong. If I may, I'll now remind you that this is why using quotes instead of facts is such a pitfall. Think about it.

 

[Barbarian]

Mammals did not evolve from therapsids. That’s more wishful thinking, nothing more.

It comes down to evidence. And as you see, the fossil, genetic, embryological, and anatomical data all show that to be a fact.

But it is a major physiological step from cold-blooded to warm-blooded creatures.

Nope. For example, some fish are warm-blooded. Many dinosaurs were, and of course, the Haversian canals in therapsids show that they were also warm-blooded. It's really just a slight increase in metabolic rates. Small bipedal dinosaurs were very active and had such rates. It's one of the reasons they had feathers. Feathers insulate, but that's only useful in a warm-blooded creature. Being warm-blooded allows higher rates of activity, and also allows activity during periods when the temperature is low. But such an adaptation requires more food, more often. So it's not surprising that it first turned up in active predators.

and just as important, how did this take place?

The evidence shows that primitive mammals, like monotremes, have a less developed homeothermy, and some even shut the process down if the temperature is too extreme. They have a lower metabolism, a temp of about 90 degrees F, as opposed to about 100 F for most placentals. So, a gradual change is what the evidence shows.

What were the necessary genetic alterations that were needed before such a change could occur?

Changes in the metabolic rate. So genes that govern thermal equilibrium had to change a bit.

And why did those highly constructive alterations occur?

See above. For certain ways of life, homeothermy is a relatively easy way to allow more activity, which is quite useful for predators.

And don't forget, evolution cannot answer the question WHY.

Surprise.

Gish gets it wrong:
"The structure of the thoracic girdle of the mammal differs fundamentally from that of the reptile. In the reptile it articulates with the breastbone by means of the coracoid bones and forms part of the thorax. This is not the case with mammals.

Barbarian observes:
The platypus has extra bones in the shoulder girdle, including an interclavicle, which is not found in other mammal

The shoulder girdle is the "thoractic girdle." Monotremes also have a coracoid, which is not found in other mammals.

How does that answer the point being raised?

Demonstrates that once again, Gish had no idea what he was talking about.

 

[Barbarian]

A new scenario of the evolutionary derivation of the mammalian diaphragm from shoulder muscles.
Hirasawa T, Kuratani S.

Recent developmental analyses indicate that the diaphragm and forelimb muscles are derived from a shared cell population during embryonic development. Therefore, the embryonic positions of forelimb muscle progenitors, which correspond to the position of the brachial plexus, likely played an important role in the evolution of the diaphragm. We surveyed the literature to reexamine the position of the brachial plexus among living amniotes and confirmed that the cervico-thoracic transition in ribs reflects the brachial plexus position. Using this osteological correlate, we concluded that the anterior borders of the brachial plexuses in the stem synapsids were positioned at the level of the fourth spinal nerve, suggesting that the forelimb buds were laid in close proximity of the infrahyoid muscles. The topology of the phrenic and suprascapular nerves of mammals is similar to that of subscapular and supracoracoid nerves, respectively, of the other amniotes, suggesting that the diaphragm evolved from a muscle positioned medial to the pectoral girdle (cf. subscapular muscle). We hypothesize that the diaphragm was acquired in two steps: first, forelimb muscle cells were incorporated into tissues to form a primitive diaphragm in the stem synapsid grade, and second, the diaphragm in cynodonts became entrapped in the region controlled by pulmonary development.
J Anat. 2013 May;222(5):504-17

The hypothesized connection turned out to be true, which is powerful evidence for it. The fact that respiration in many reptiles is tied to the movement of limbs to pump the lungs, makes this hypothesis even more likely. Again, instead of a new function, an old one is retained and specialized, while a second one is lost.

It's a common theme in evolution, as the case of the mammalian ear shows.

 

[Asyncritus]

You cited Gish as an authority; and with that, you put his credibility on the table. That's how it works. If you'd rather go with evidence instead of quotes, it won't happen.

And yet, you, quite hypocritically, began this thread with a huge quote from evolutionarily biased palaeontologists. Some consistency is needed here.

Example of Gish's competence to discuss biology:
"But, on the other hand, if you look at certain proteins, you will find that man is more closely related to a bullfrog than he is to a chimpanzee."

Whether Gish said so or not is a moot point. You are now quoting him - the very thing you seem to disagree with.

"As mentioned earlier, evolutionists believe that as the bones in the reptilian jaw, except for the dentary, gradually became relieved of their function in the jaw they were now free either to evolve out of existence or to assume some new function. "
Gish is apparently unaware that those bones connect to the middle ear, even though they are attached to the lower jaw.​

This is again sheer nonsense. As the following diagram shows, the connection is at best tenuous. Your diagram is very misleading. Did you get it from talkorigins?

Here are two better ones.

You don't learn anything, do you?

Just look. In the reptile there is a single bone connecting the eardrum to the inner ear. The stapes.

Notice that the quadrate and the articular are nowhere to be seen. They perform no function whatsoever in hearing by the reptile. They may receive vibrations, but it is certainly wrong to say that they play a part in hearing.

No, that's wrong, as you learned earlier. Let's take a look...

,

As you see, the reptilian jaw is connected to the ear, via the quadrate and articular bones. This is why reptiles put their lower jaws to the ground to better pick up sounds.

Your diagram is duff, and has misled you. In any case, you have failed to notice that the articular is not connected to the quadrate. It is in fact a part of the LOWER jaw.

Your diagram maker is trying his hardest to falsify the evidence and make it look as if there is a close connection between the tympanic membrane and the quadrate. This is entirely false, as you can see. If the quadrate COVERED the tympanic membrane as in that ridiculous diagram, then the animal simply couldn't hear.

Now face up to the problems.

First, the quadrate AND the articular are BOTH OUTSIDE THE MIDDLE EAR in reptiles. The articular is firmly attached to the lower jaw, and the quadrate equally firmly attached to the upper jaw.

Neither is loose, and capable of rattling round in the animal's head. Far less are they capable of "migrating" into the middle ear.

How do you account for the silly concept that they did so migrate?

Readers, just look at those diagrams again, and remark on that incredible concept that those 2 outer bones somehow 'migrated' through the eardrum, somehow got them selves stuck between the eardrum and the stapes, somehow arranged themselves into the correct shapes and sizes required, and hey, bingo, a mammalian ear was formed.

Does it seem possible given that it is only genetic mistakes, otherwise known as mutations, that are responsible for the entire reconstruction of the reptilian ear?

Gish was perfectly right to draw your attention to these facts, and you cannot gainsay them in any form or fashion:

"Thus, the quadrate and articular bones of the jaw became free (they were, by the way, firmly attached to the dentary in Morganucodon) and somehow worked their way into the middle ear to eventually become the incus and malleus, respectively."

"Now the anatomical problems associated with such a postulated process are vastly greater than merely imagining how two bones precisely shaped to perform in a powerfully effective jaw-joint could detach themselves, force their way into the middle ear, reshape themselves into the malleus and incus, which are precisely engineered to function with a remodeled stapes in a vastly different auditory apparatus, while all at the same time the creature continues to chew and to hear! "

Hear hear! Dr Gish!



Come Barbarian. Give it up. You're on to another loser here.

I'm not going on tonight with this nonsense. I'm going to wax lyrical about evolutionary optimism and general stupidity, and going to get infracted again.

But please, apply a bit of common sense, would you?

Just a passing point.

Do you notice in your diagram above, THERE IS NO TYMPANIC MEMBRANE (eardrum) in the reptile ear? Where is it? More falsification of the evidence,

We have discussed this before. Gish just didn't realize how it worked.

You obviously don't realise that reptiles have an eardrum! So who's worse? You or Gish?

 

[Asyncritus]

A new scenario of the evolutionary derivation of the mammalian diaphragm from shoulder muscles.
Hirasawa T, Kuratani S.
.

Don't these guys have any idea of where the shoulder and diaphragm are??????

And you're busy listening to this tripe!

Oh dear. I'm going to get infracted, I'm laughing so hard! Sorry Sparrow.

 

[Asyncritus]

As I'm here, let me draw you and the readers' attention to an interesting fact about the mammalian ear, which cannot be attributed to the god natural selection.

​

Look at the stapes in the human ear.

It is resting and attached to a fenestra vestibuli, which is a flexible membrane which moves in and out as the stapes vibrates. With me so far?

The cochlea (means a snail, and you can see why) is surrounded by fluid, and the chamber is a sealed chamber in which it fits.

Now fluids don't compress at all, or exceedingly little.

So if the stapes is trying to vibrate the fenestra, it simply wouldn't work, because the fluid inside the inner ear would prevent it from vibrating in and out as it's supposed to do.

So what did the All Wise do?

He placed the second fenestra, the round window, just below the stapes. That second fenestra is also flexible, and as the stapes vibrates and pushes the top window in and out, the pressure is relieved by the opposite movement of the round window.

Result? The stapes can vibrate, and the vibration can be transmitted to the cochlea and converted into electrical impulses which are sent to the brain for interpretation.

Natural selection invent such a thing? Bah.​