falconjudge wrote:I'm pretty sure it is. We must respect his views until he posts them and we are able to properly evaluate their contents.

Well, his views are pretty clearly bullshit, no problem there. That's not a personal insult.

On the subject of flow through lungs ... we have the following papers:

Basic Avian Pulmonary Design And Flow-Through Ventilation In Non-Avian Theropod Dinosaurs by Patrick M. O'Connor & Leon P. A. M. Claessens, Nature, 436: 253-256 (14th July 2005) [Full paper downloadable from here]

O'Connor & Claessens, 2005 wrote:Birds are unique among living vertebrates in possessing pneumaticity of the postcranial skeleton, with invasion of bone by the pulmonary air-sac system1–4. The avian respiratory system includes high-compliance air sacs that ventilate a dorsally fixed, non-expanding parabronchial lung2,3,5,6. Caudally positioned abdominal and thoracic air sacs are critical components of the avian aspiration pump, facilitating flow-through ventilation of the lung and near-constant airflow during both inspiration and expiration, highlighting a design optimized for efficient gas exchange2,5–8. Postcranial skeletal pneumaticity has also been reported in numerous extinct archosaurs including non-avian theropod dinosaurs and Archaeopteryx9–12. However, the relationship between osseous pneumaticity and the evolution of the avian respiratory apparatus has long remained ambiguous. Here we report, on the basis of a comparative analysis of region-specific pneumaticity with extant birds, evidence for cervical and abdominal air-sac systems in non-avian theropods, along with thoracic skeletal prerequisites of an avian-style aspiration pump. The early acquisition of this system among theropods is demonstrated by examination of an exceptional new specimen of Majungatholus atopus, documenting these features in a taxon only distantly related to birds. Taken together, these specializations imply the existence of the basic avian pulmonary Bauplan in basal neotheropods, indicating that flow-through ventilation of the lung is not restricted to birds but is probably a general theropod characteristic.

Further on in that paper we read:

O'Connor & Claessens, 2005 wrote:The general pattern of pneumaticity in Majungatholus is expressed throughout Theropoda (see Supplementary Table 1), being evident in representatives of all major neotheropod clades (Fig. 2). Sacral pneumaticity is present in at least some members of abelisauroid, spinosauroid, allosauroid, ornithomimid, tyrannosauroid and maniraptoran clades, indicating a consistent and widespread pattern of pneumatic invasion by caudally located air sacs in non-avian theropods. The postcranial pneumaticity observed in non-avian theropods implies the potential for a degree of pulmonary air sac development similar to that observed only in living birds.

Skeletal and soft-tissue specializations in the cranial half of the avian trunk maintain a near-constant volume of the pulmonary cavity2,5,6. Movements of the sternum, ribs and pectoral girdle change trunk volume to create pressure differences that drive ventilatory airflow2,6,22,23. Cineradiographic (high-speed X-ray film) studies of skeletal and visceral kinematics during lung ventilation show greater expansion of the ventrocaudal trunk, with a larger ventral excursion of the caudal sternal margin relative to the cranial sternal margin (see Supplementary Table 2 and Supplementary Movie 1). As a result, the largest ventilatory volume changes are produced caudal to the exchanger (lung), establishing the necessary pressure gradient required for flow-through ventilation.

Skeletal adaptations consistent with an avian-like aspiration pump are already present in basal neotheropods, including a relatively rigid thoracic vertebral column with accessory hyposphene–hypantra articulations and a robust cranial thorax. In the cranial ribcage, the vertical arrangement of the diapophysis and parapophysis, the two vertebral joints that articulate with the two heads of each rib, ensures a rigid and relatively incompressible skeletal framework around the pulmonary cavity. The orientation of the vertebrocostal articulations gradually changes to a horizontal position between thoracic vertebrae 4 and 9, thereby allowing larger lateral excursions of the more caudally positioned ribs. The greater capacity for lateral excursion of these ribs in theropods, along with movements of the gastralial apparatus, a system recently proposed to work as a ventrally positioned accessory aspiration pump24, provides a mechanism for establishing greater volumetric changes in the caudal half of the theropod trunk, a key characteristic essential for establishing flow-through ventilation in birds6–8.

We predict that in any biophysical model for the evolution of flowthrough ventilation, areas of increased lung compliance must initially be located caudal to the gas-exchange portion of the pulmonary apparatus. It is only when higher-compliance air sacs are positioned caudal to the lung that air will be moved through it on ventilation. An initial cranial position for air sacs, as has been predicted previously for theropods18,19, would result only in expansion/contraction of the cranial air sac, and would serve little role in ventilating a caudally positioned lung. Ancillary evidence for this model comes from extant non-avian sauropsids that also possess similarly heterogeneous pulmonary systems. Although not serving ventilatory roles, nor pneumatizing the postcranial skeleton, air sacs or diverticular complexes develop on the caudal end of the lung in chameleons, varanids and snakes3,6, indicating that the caudalmost region of the sauropsid lung might be relatively plastic. Sacral pneumaticity in theropod dinosaurs, the basis for inferring caudally positioned air sacs, is consistent with a ‘caudal origin model’ and establishes the potential for flow-through ventilation in the dinosaurian ancestors of living birds.

So, the emergence of skeletal features allowing pneumaticity of the skeleton to take place, and the existence of extant reptiles exhibiting caudal air sacs behind the lung, structurally akin to a prototype version of the system present in modern birds, establishes the evidence that flow through lungs emerged in Theropod taxa some time before the emergence of birds.

Shrunk wrote:

falconjudge wrote:I'm pretty sure it is. We must respect his views until he posts them and we are able to properly evaluate their contents.

Well, his views are pretty clearly bullshit, no problem there. That's not a personal insult.

We mustn't respect shit but the FUA. I didn't call him anything, I merely asked why the people who push bullshit so frequently also can't use the quote-function properly? I don't understand why there should be a correlation there. After all, given the sheer amounts of shit-filled technical jargon (Complex Specified Information anyone?) these people can fabricate in support of their doctrines, you'd think simply pressing the QUOTE button would be peanuts to them.

Shrunk wrote:

Animavore wrote:Birds actually have scales on their legs. This is especially prominent on large birds. You can see this on my friend's turkeys. As you look up the leg you actually see the scales begin to become more perpendicular to the leg, elongated and feathery, quite quickly, as they near the top of the leg. I really don't see the problem there with that one. Once you pluck a turkey there's no scales under the feathery parts, because the feathers are the scales.

Interesting. So a series "transitional forms" right there on an organism that actually lives in the present day. But creationists insist there are no "transitional forms." How could that be? They'd have to be either stupid, ignorant or dishonest to make such a claim.

Hey...don't sell them short.

They can very well be all three.

Rumraket wrote:

Shrunk wrote:

falconjudge wrote:I'm pretty sure it is. We must respect his views until he posts them and we are able to properly evaluate their contents.

Well, his views are pretty clearly bullshit, no problem there. That's not a personal insult.

We mustn't respect shit but the FUA. I didn't call him anything, I merely asked why the people who push bullshit so frequently also can't use the quote-function properly? I don't understand why there should be a correlation there. After all, given the sheer amounts of shit-filled technical jargon (Complex Specified Information anyone?) these people can fabricate in support of their doctrines, you'd think simply pressing the QUOTE button would be peanuts to them.

it is an interesting correlation, I agree.

Anyway, hopefully asyncritus will soon be back to tidy up his post. If he does, maybe he can then start actually talking about evolution. So far he has just been arguing against saltationism. I'm not sure why he would be doing that, since no one here, and few people elsewhere, actually believe that occurs.

Fistly, learn to use the quote function. I know nested quotes can be tricky, but you don't need to use them, simply put a [qoute] tag before each block of my text you want to quote and a [/qoute] tag after it and that would suffice. Or quote this post and look at how I did it.

asyncritus wrote:HI H,

Thanks for doing me the great honour! I'm going to demonstrate my ingratitude now!

halucigenia wrote:

asyncritus wrote:
Let me grant you that mutations + natural selection produced a bird's wings (for instance) from a reptile's forelimbs. Wildly improbable, of course, but let's suppose. And feathers from scales.

Well, feathers are just modified scales, so no problem there, as they could have had uses other than flight to start with.

Now where did you get that piece of nonsense from, I wonder? Have you ever had a look at the difference between any given scale and say, a flight feather? This is an iguana, which has a load of different types of scale on its body.

Which do you fancy is the best candidate for turning into a flight feather? I personally don't see any hope, but perhaps you can tell me.

Different types of scale/feather are simply different types, it matters not which evolved into what, the point is that feathers are considered to have evolved from scales. It is a fact that utility drives evolution therefore if a modified scale conferred an advantageous utilitarian function it could have been selected for. The point is that they simply did not have to evolve “for” flight.

asyncritus wrote:And here's a diagram of a flight feather structure:

Add to that the difficulty that there are about 10 different types of feather ON A SINGLE BIRD, your problems increase exponentially.

So what? Different types of feather evolved as they provided different and more beneficial utility functions over their preceding scale like forms. feathers may have evolved from one type of scale or many different types of scale, after all , they are modified scales. Different types of feather are all modifications on a theme derived from an existing structure – the scale. Modifications of existing structures is how evolution works. I see no evolutionary problems to your weak argument/objection.

asyncritus wrote:

halucigenia wrote:

asyncritus wrote:, and endothermic metabolism from ectothermic metabolism.

Theropod dinosaurs could have been endothermic before they evolved flight so, no problem there either.

Could, could, could... Sure pigs can't fly?

All that is required to refute your argument is to propose something that could have happened in a different way than your straw man caricatures would have it. Again you miss the point – your assertion is that all of these features had to evolve together to confer flight. I am simply pointing out that it did not have to happen like you assert it should.

asyncritus wrote:

halucigenia wrote:

asyncritus wrote:Not to mention the entirely new lung structure, in which air enters the lung on exhalation rather than on inhalation.

again, something that could have evolved in theropod dinosaurs prior to wings and flight, so, again there is no problem there either.

No, I'm not having that either. Here are two diagrams of the structures involved:

Honestly, H, can you see any possible way for the left type lungs to become the right type lungs? I can't see it myself, but maybe you can. If you can't, then you're admitting that brainless, blind, and purposeless mutation plus natural selection is much more intelligent than we are. Well, you are maybe!

Natural selection is the blind watchmaker, it requires no intelligence, what evolves is simply contingent on what has gone before. Evolution is a non-teleological process it does not require purposefulness. These processes therefore do not require a brain to operate and so are brainless. You again miss the point that I was making – that of the fact that your original argument requires these things to all have evolved at once for the purpose of flight, or at least that's how I understood your argument. You even conceded that, for the purpose of argument, that these features could have evolved when you stated “Let me grant you that mutations + natural selection produced...” That was the preamble to your argument, have you now taken that concession back? Must we really argue about how these individual separately evolved traits could have arisen?

asyncritus wrote:

halucigenia wrote:

asyncritus wrote:All that by the magic of waving the old Random Mutation Selection wand. (Has common sense completely deserted your halls???)

No magic required, all of the examples that you have provided so far could have evolved prior to the evolution of wings and flight. If that is what you are getting at.

But why should they do so? Surely you're not saying that an organ/metabolism/whatever else can evolve IN ADVANCE of being needed. Somebody said words to the effect that something can't evolve in the Cambrian because it might be of use in the Jurassic. So true.

Of course I am not remotely suggesting such a thing.
You just love to twist other peoples words by deliberate misinterpritation, don't you. Oh, I remember your argumentative style now.
What I am suggesting is that these traits simply did not evolve “for” flight but evolved as they were beneficial in some other respect for the organism at the time that they evolved. There is simply no reason that they should evolve in advance of being needed, they were never “needed” for anything in the future they were simply utilised in their present as and when they evolved. The the way in which flight evolved in theropod dinosaurs is simply contingent on evolutionary traits that had already evolved in the theropod lineage, theropods evolved feathers, exothermic metabolisms and modified lung structures, so that is what we see in their modern descendants – the birds. In much the same way that the evolution of flight in mammals or insects is contingent on the evolutionary traits that their respective lineages acquired i.e. they did not “need” to evolve feathers to evolve flight.

asyncritus wrote:

halucigenia wrote:
Why?
Why is there no other way for this to happen?

To be perfectly honest, when I add up the vast differences between a bird and any given reptile, the impossibility of one evolving from the other becomes positively gargantuan. I've indicated some of the difficulties above, and I'm sure that even you can feel the force of some of those points.

The only force I feel is that of hot air and bluster. You are looking at endpoints of branches again and still trying to bridge that gap between the endpoints – the one that has no need of being bridged. You never did understand the tree analogy I explained to you two years ago on the OU forums did you? You have to look along the branches, not between them, for the possible pathways.
Looking at extant organisms and concluding “the impossibility of one evolving from the other” is positively gargantuan, it is a gargantuan misunderstanding of what the theory of evolution actually proposes.

asyncritus wrote:

halucigenia wrote:
Why can birds not have gradually evolved over time from reptilian ancestors via theropod dinosaurs?

They could evolve from fish as far as I'm concerned. The question I'm asking is a deeply fundamental one.
For A to evolve into B, there are major instinctual questions that need some sort of evolutionary answer. For any function, not existent in A, but existing in B, there MUST be pre-existing instincts powering that function, which have entered the genome. (The whole question is raised, expanded and answered in the book 'How does instinct evolve'. You'll find it on google somewhere.)

The question you are asking is a deeply flawed one. Let me rephrase it for you;
For any function, not existent in A, but existing in B, there MUST be pre-existing instincts that have evolved in parallel powering utilising that function, which have entered evolved in the genome from modified pre-existing instinctual behaviours. There FIFY.

asyncritus wrote:

halucigenia wrote:
Why can feathers not have gradually evolved in this lineage which provided utility in ways other than flight – insulation or display for example?

Are yo asking me why a blanket can't evolve into a wing?

No I am asking why a structure can not be modified by evolution in a multitude of ways to provide benefit to an organism in different ways than they currently do.

asyncritus wrote:

halucigenia wrote:
Why can an organisms’ metabolism not change from providing little excess body heat to providing more and more body heat over time?

Because the physiology of an ectotherm is very, very different to an endotherm. The amount of heat required to support an andotherm is wildly different to that required by an ectotherm.

Yes, the physiologies differ, different physiologies is what evolution does.

asyncritus wrote:

halucigenia wrote:
Why can lungs not be modified by random mutation and natural selection from a simple air sac to one with flow through functionality?

Because any of the changes required in that change would be immediately fatal. I might as well quote Denton's remarks on the subject for you. You know he's an evolutionist, but not the usual starry-eyed variety.

Just how such an utterly different respiratory system could have evolved gradually from the standard vertebrate design is fantastically difficult to envisage, especially bearing in mind that the slightest malfunction leads to death within minutes.

So one mutation affecting the structure of the lung meant death immediately. One mutation producing a hole in the bottom of the lung meant death. So where do you go from there?

I smell a quotemine. Yes, many things that have evolved are “fantastically difficult to envisage” however relying on this as an argument is simply relying on personal incredulity.
A quotemine, an appeal to authority and personal incredulity all rolled into one. Urgh

asyncritus wrote:

halucigenia wrote:Just what do you think actually prevents these things from happening.
And, remember, personal incredulity is not a valid argument.

I don't argue from incredulity.

Yes you do, you did so just above

asyncritus wrote:I make inferences to the best explanation, something that all science does all the time.

You have never yet proposed a better explanation than evolutionary theory. If you infer something as a better explanation then let’s hear how it is proposed to work, what are it's mechanisms etc.
You cannot even answer the straightforward question of “what do you think actually prevents these things from happening” never mind proposing a better explanation. I will not hold my breath.

asyncritus wrote:

halucigenia wrote:

asyncritus wrote:1 What could the new bird do with the brand new flight apparatus? After all, he's still a reptile in his head. Can you see it? 'Duhhhh! What the hell do I do with these things'? Jumps off cliff. THUDDD! End of bird evolution.

Do we really have to go there again? You sound like you have been to the Stevebee School of argumentation.
No one, except creationist straw man arguments, propose that an organism suddenly appeared with brand new novel adaptions like a full set of flight apparatus within a single generation.

Richard Goldschmidt certainly thought so, or he would never have proposed his Hopeful Monster theory. He knew the facts (such as I've been outlining above) and couldn't produce any kind of sensible explanation. I can't remember reading anyone producing a proper account of how it could have happened, so maybe you can point me in the right direction toward one of them.

Goldschmidt proposed his macro-mutational theory to get around problems that have now largely been solved He was just plain wrong that macro-mutations should be necessary for evolutionary change, and even he would not propose something as absurd as you have given as an example.

asyncritus wrote:You see, if the whole thing didn't appear in one go, then of what use was the intermediate? Szent-Gyorgi proposed his negentropy theory, but the new Law of Asynctropy takes the whole thing to a new level. It says that Every one of the functions of life depends on a POWERING INSTINCT. If the powering instinct is not present or available, THEN THE FUNCTION ITSELF IS ABSENT OR IMPOSSIBLE even if the necessary organ is present.

Which is a pretty profound and far reaching statement of fact. Give it some thought.

The little thought it requires has been duly given and given the fact that instincts are also under the control of genes, both modifications to the genetic components that give rise to new and modified instincts and the traits that those instincts may control can arise due to mutation and selection then it is not a problem for the theory of evolution in the way that you infer.

asyncritus wrote:

halucigenia wrote:

asyncritus wrote:
It requires empowering flight instincts - or it couldn't get off the ground, no matter how good the wings etc may be. Think of a fighter plane with an untrained administrative clerk at the controls. Disaster on the way? You bet.

Not all flight ability is instinctual, have you never seen young birds on nature documentaries stretching their wings and learning how to fly. Again, no one except creationists’ straw man arguments propose that an organism suddenly appeared with brand new novel adaptions like a full set of flight instincts within a single generation.

Sure I've seen them doing that. We all have, I'm sure. But I could spread my wings till the cows come home, and all I'd succeed in doing is breaking my neck every time I jumped off a roof.

THE ABILITY TO LEARN HOW TO FLY MUST BE THERE, or the wings are useless. It's that instinct again.

Remember if Critter A learns how to fly without breaking it's neck, then it CANNOT pass that information down to its offspring who have to start from scratch again - otherwise you're in Lamarckism again. (But I see Dawkins trying to sneak it in by the back door again! Why, because he knows just how ridiculous his theory really is).


Don't you see how hopless ( } that proposition really is? Bird A (with 1 wing) flaps, is spotted by a predator, gets eaten and the whole thing has to start again.

Bird B (with 1 wing) flaps, is eaten by a predator..... la de da.

I don't see things progressing very far, do you?

You are just using bait and switch here in your argument. First you are invoking instinctual behaviour then describing learned behaviour these are two different things. No one is suggesting that learned behaviour requires to become instinctual behaviour except for you, that is your strawman argument.
There are two separate components to the behaviour that allows birds to fly. One is instinctual – that urges the young bird to stretch and flap this is passed on as a genetic component. The other is learned behaviour – that enables the young bird to learn how, when it flaps those wings, they respond to the wind etc. this learned behaviour cannot and does not need to be passed on to the next generation as each generation goes through the same learning procedure. What does get passed on is the ability to learn, the genetic propensity for neurons to be able to be “programmed” by repeated successful behaviours within each generation. No Lamarckism required.

asyncritus wrote:

halucigenia wrote:

asyncritus wrote:
3 And how did they enter the genome?

How do any behaviours originate and evolve, there’s nothing magical that has to “enter” the genome, behaviours and the ability to learn do have a genetic component which can be modified and change over time just like any other trait under genetic control.

Again, here's Bird A who's got the equipment, but can't fly. He takes off, narrowly avoids breaking his fool neck, survives and reproduces. How does the information regarding flight enter the genome? Answer, it can't.

But that information MUST enter the genome somewhere along the line - otherwise birds can't fly, ever. So where and how? I read somewhere that some Chinese palaeontologist found the most ancient bird fossils, and the bird could fly. Well it got those flight instincts somewhere. But where?

Already answered above.

asyncritus wrote:

halucigenia wrote:

asyncritus wrote:
Remember, Lamarckism is dead, and cannot make any contribution here.

Yes and no one, except creationists’ straw man arguments propose that any Lamarckian process is required for instincts to arise and evolve.

You are forced to do so, that's for certain, much as you may object.

Here we are again:

A (can't fly) --------------X---------------> B (can fly)

How many X's do you want? How many intermediates between A and B? It matters not. Somewhere in that chain, one of them learned to fly AND PASSED THE INFO DOWN TO OFFSPRING.

Unless of course, you want to say that suddenly, a whole flock of fliers appeared. Which is merely another word for creation.

As I see it, you are on some pretty painful horns here. The instinct question, detailed in How Does Instinct Evolve, will kill off evolution theory once this new development of it becomes known.

Just stop it with the bait and switch and equivocation between instinctual behaviours and learned behaviours will you. They are separate things, learned behaviours are not proposed to become instinctual that is your strawman. Therefore there is no need to invoke Lamarckism.
The only dilemma here is a false dilemma one with horns that are completely imaginary and of your own making.

asyncritus wrote:

halucigenia wrote:

asyncritus wrote:

But nice to see you here and it’s nice to have a new chew toy.

Thanks. I had forgotten our previous encounters.

So had I until now, shudder.

Crude structure conveys evolutionary advantage even if used inefficiently -> instinctually more efficient use of crude structure conveys new advantage -> refined structure conveys new advantage -> better instinctual use conveys new advantage -> better refined structure conveys new advantage...

Allowing...
Stabilisation -> gliding -> flying (or similar progression)

I'm afraid that I struggle to see the difficulty that you are experiencing with this concept asyncritus.

Precambrian Rabbi wrote:Crude structure conveys evolutionary advantage even if used inefficiently -> instinctually more efficient use of crude structure conveys new advantage -> refined structure conveys new advantage -> better instinctual use conveys new advantage -> better refined structure conveys new advantage...

Allowing...
Stabilisation -> gliding -> flying (or similar progression)

I'm afraid that I struggle to see the difficulty that you are experiencing with this concept asyncritus.

He doesn't want to understand it, he's here to try and produce converts, not find out how evolution works. People who want to learn how/if something works, usually don't peddle specious propaganda. There's a difference between saying "Guys, there's this issue I'm having with concept XYZ, because I don't see how it could happen if bla bla bla, could you shed some light on the issue?", and instead producing common creationist quotemines and objections, as asyncritus has done in the various threads he's infested.
This is why this thread is now in Debunk it > Creationism, not the Biology subforum, because this discussion isn't about explaining scientific concepts to an honest and curious individual who may lack the requisite foreknowledge or who's been misinformed but genuinely wants to know. No, given the quite obvious trolling nature and various silly little, but fundamentally hostile taunts, in all of asyncritus posts, this is simply a thread devoted mostly to onlookers.

falconjudge wrote:Also, this is assuming that the feathered dinosaurs could fly or were built to fly right away. Which is, quite frankly, hilarious.

Absolutely correct.

So they acquired the ability to fly and passed it down to their descendants.

That what you're saying Dr Lamarck?

asyncritus wrote:

falconjudge wrote:Also, this is assuming that the feathered dinosaurs could fly or were built to fly right away. Which is, quite frankly, hilarious.

Absolutely correct.

So they acquired the ability to fly and passed it down to their descendants.

That what you're saying Dr Lamarck?

Can you understand English? Or have you just mastered the creationist arts of misrepresentation and quote mining?

asyncritus wrote:

falconjudge wrote:Also, this is assuming that the feathered dinosaurs could fly or were built to fly right away. Which is, quite frankly, hilarious.

Absolutely correct.

So they acquired the ability to fly and passed it down to their descendants.

That what you're saying Dr Lamarck?

Completely backwards.

Those that were born with a better ability to fly (or glide, etc.) in an environment that favoured that ability would tend to have more babies. That would tend to propogate that improved ability. Rinse and repeat.

Calilasseia wrote:On the subject of flow through lungs ... we have the following papers:

Basic Avian Pulmonary Design And Flow-Through Ventilation In Non-Avian Theropod Dinosaurs by Patrick M. O'Connor &

Birds are unique among living vertebrates in possessing pneumaticity of the postcranial skeleton, with invasion of bone by the pulmonary air-sac system1–4. The avian respiratory system includes high-compliance air sacs that ventilate a dorsally fixed, non-expanding parabronchial lung2,3,5,6. Caudally positioned abdominal and thoracic air sacs are critical components of the avian aspiration pump, facilitating flow-through ventilation of the lung and near-constant airflow during both inspiration and expiration, a design optimized for efficient gas exchange

You were saying, Calilasseia?

Postcranial skeletal pneumaticity has also been reported in numerous extinct archosaurs including non-avian theropod dinosaurs and Archaeopteryx9–12. However, the relationship between osseous pneumaticity and the evolution of the avian respiratory apparatus has long remained ambiguous. Here we report, on the basis of a comparative analysis of region-specific pneumaticity with extant birds, evidence for cervical and abdominal air-sac systems in non-avian theropods, along with thoracic skeletal prerequisites of an avian-style aspiration pump.

The early acquisition of this system among theropods is demonstrated by examination of an exceptional new specimen of Majungatholus atopus, documenting these features in a taxon only distantly related to birds. Taken together, these specializations imply the existence of the basic avian pulmonary Bauplan in basal neotheropods, indicating that flow-through ventilation of the lung is not restricted to birds but is probably a general theropod characteristic.

This is sheer nonsense. The existence of post-cranial air sacs does not constitute evidence for a flow through ventilation. It presents evidence for the existence of postcranial air sacs, nothing else.

If it occurs in reptilian species, then it exists alongside a balloon-like lung. That balloon-like lung is not, and cannot be a flow through arrangement. This subtle point seems to have eluded their mammoth intellects. Strike one.

O'Connor & Claessens, 2005 wrote:The general pattern of pneumaticity in Majungatholus is expressed throughout Theropoda (see Supplementary Table 1), being evident in representatives of all major neotheropod clades (Fig. 2). Sacral pneumaticity is present in at least some members of abelisauroid, spinosauroid, allosauroid, ornithomimid, tyrannosauroid and maniraptoran clades, indicating a consistent and widespread pattern of pneumatic invasion by caudally located air sacs in non-avian theropods. The postcranial pneumaticity observed in non-avian theropods implies the potential for a degree of pulmonary air sac development similar to that observed only in living birds .

'Implies the potential' being translated means that it doesn't exist in the reptilian groups mentioned. Strike two.

[...]

The orientation of the vertebrocostal articulations gradually changes to a horizontal position between thoracic vertebrae 4 and 9, thereby allowing larger lateral excursions of the more caudally positioned ribs. The greater capacity for lateral excursion of these ribs in theropods, along with movements of the gastralial apparatus, a system recently proposed to work as a ventrally positioned accessory aspiration pump24, provides a mechanism for establishing greater volumetric changes in the caudal half of the theropod trunk, a key characteristic essential for establishing flow-through ventilation in birds6–8.

Therefore the flow through ventilation has not been established. Therefore this paper is irrelevant to the issue being discussed. Strike three.

They've also missed the point that the bird thorax does not expand and contract during respiration:

The key to the system is that distention and compression of the air sacs, not the lungs, moves air in and out and that at any given moment air may be moving into and out of the lung and being "parked" in the air sacs. The lungs are stiff and noncompliant, not at all like the distensible lungs of mammals. The air sacs act as "bellows" to suck air in and blow it out, and also to hold part of the total volume. http://www.vetmed.vt.edu/education/Curr ... rdresp.htm
{...}

So, the emergence of skeletal features allowing pneumaticity of the skeleton to take place, and the existence of extant reptiles exhibiting caudal air sacs behind the lung, structurally akin to a prototype version of the system present in modern birds, establishes the evidence that flow through lungs emerged in Theropod taxa some time before the emergence of birds.

The conclusion is entirely unjustified, and the paper as a whole has completely failed to address the main points at issue.

The biggest failure lies in the inability of the authors to establish even the possibility that these air sacs could somehow connect to the lungs themselves in the way required: so the air ENTERS THE LUNGS ON EXHALATION, NOT ON INHALATION.. It must be obvious to the meanest intellect that this is an impossibility, given the reptilian starting point where the EXACT OPPOSITE IS OCCURRING.

Your paper fails entirely to address this main issue.

There is the additional question, not even mentioned, that birds do not have a diaphragm, but reptiles do. Where has the diaphragm gone? Why has it disappeared, when it functions properly, correctly and effectively in reptiles of today?

As far as the birds are concerned, there is no need for a diaphragm. As quoted above, the air sacs perform the function: The air sacs act as "bellows" to suck air in and blow it out, and also to hold part of the total volume.

There is no halfway house possible. If the reptiles have a diaphragm, instrumental in causing air to enter and leave the lungs, then any disappearance of that structure, partial or total, means immediate death.

Not too good for evolution, as I'm sure you will agree.

asyncritus wrote:

Calilasseia wrote:On the subject of flow through lungs ... we have the following papers:

Basic Avian Pulmonary Design And Flow-Through Ventilation In Non-Avian Theropod Dinosaurs by Patrick M. O'Connor &

Birds are unique among living vertebrates in possessing pneumaticity of the postcranial skeleton, with invasion of bone by the pulmonary air-sac system1–4. The avian respiratory system includes high-compliance air sacs that ventilate a dorsally fixed, non-expanding parabronchial lung2,3,5,6. Caudally positioned abdominal and thoracic air sacs are critical components of the avian aspiration pump, facilitating flow-through ventilation of the lung and near-constant airflow during both inspiration and expiration, a design optimized for efficient gas exchange

You were saying, Calilasseia?

Postcranial skeletal pneumaticity has also been reported in numerous extinct archosaurs including non-avian theropod dinosaurs and Archaeopteryx9–12. However, the relationship between osseous pneumaticity and the evolution of the avian respiratory apparatus has long remained ambiguous. Here we report, on the basis of a comparative analysis of region-specific pneumaticity with extant birds, evidence for cervical and abdominal air-sac systems in non-avian theropods, along with thoracic skeletal prerequisites of an avian-style aspiration pump.

The early acquisition of this system among theropods is demonstrated by examination of an exceptional new specimen of Majungatholus atopus, documenting these features in a taxon only distantly related to birds. Taken together, these specializations imply the existence of the basic avian pulmonary Bauplan in basal neotheropods, indicating that flow-through ventilation of the lung is not restricted to birds but is probably a general theropod characteristic.

This is sheer nonsense. The existence of post-cranial air sacs does not constitute evidence for a flow through ventilation. It presents evidence for the existence of postcranial air sacs, nothing else.

If it occurs in reptilian species, then it exists alongside a balloon-like lung. That balloon-like lung is not, and cannot be a flow through arrangement. This subtle point seems to have eluded their mammoth intellects. Strike one.

O'Connor & Claessens, 2005 wrote:The general pattern of pneumaticity in Majungatholus is expressed throughout Theropoda (see Supplementary Table 1), being evident in representatives of all major neotheropod clades (Fig. 2). Sacral pneumaticity is present in at least some members of abelisauroid, spinosauroid, allosauroid, ornithomimid, tyrannosauroid and maniraptoran clades, indicating a consistent and widespread pattern of pneumatic invasion by caudally located air sacs in non-avian theropods. The postcranial pneumaticity observed in non-avian theropods implies the potential for a degree of pulmonary air sac development similar to that observed only in living birds .

'Implies the potential' being translated means that it doesn't exist in the reptilian groups mentioned. Strike two.

[...]

The orientation of the vertebrocostal articulations gradually changes to a horizontal position between thoracic vertebrae 4 and 9, thereby allowing larger lateral excursions of the more caudally positioned ribs. The greater capacity for lateral excursion of these ribs in theropods, along with movements of the gastralial apparatus, a system recently proposed to work as a ventrally positioned accessory aspiration pump24, provides a mechanism for establishing greater volumetric changes in the caudal half of the theropod trunk, a key characteristic essential for establishing flow-through ventilation in birds6–8.

Therefore the flow through ventilation has not been established. Therefore this paper is irrelevant to the issue being discussed. Strike three.

They've also missed the point that the bird thorax does not expand and contract during respiration:

The key to the system is that distention and compression of the air sacs, not the lungs, moves air in and out and that at any given moment air may be moving into and out of the lung and being "parked" in the air sacs. The lungs are stiff and noncompliant, not at all like the distensible lungs of mammals. The air sacs act as "bellows" to suck air in and blow it out, and also to hold part of the total volume. http://www.vetmed.vt.edu/education/Curr ... rdresp.htm
{...}

So, the emergence of skeletal features allowing pneumaticity of the skeleton to take place, and the existence of extant reptiles exhibiting caudal air sacs behind the lung, structurally akin to a prototype version of the system present in modern birds, establishes the evidence that flow through lungs emerged in Theropod taxa some time before the emergence of birds.

The conclusion is entirely unjustified, and the paper as a whole has completely failed to address the main points at issue.

The biggest failure lies in the inability of the authors to establish even the possibility that these air sacs could somehow connect to the lungs themselves in the way required: so the air ENTERS THE LUNGS ON EXHALATION, NOT ON INHALATION.. It must be obvious to the meanest intellect that this is an impossibility, given the reptilian starting point where the EXACT OPPOSITE IS OCCURRING.

Your paper fails entirely to address this main issue.

There is the additional question, not even mentioned, that birds do not have a diaphragm, but reptiles do. Where has the diaphragm gone? Why has it disappeared, when it functions properly, correctly and effectively in reptiles of today?

As far as the birds are concerned, there is no need for a diaphragm. As quoted above, the air sacs perform the function: The air sacs act as "bellows" to suck air in and blow it out, and also to hold part of the total volume.

There is no halfway house possible. If the reptiles have a diaphragm, instrumental in causing air to enter and leave the lungs, then any disappearance of that structure, partial or total, means immediate death.

Not too good for evolution, as I'm sure you will agree.

Its interesting how you say, this is nonsense / impossible etc... and try to rip evidence apart when you can't present your own to challenge the journals Cali uses? Please present journals that has evidence that can be verified by other scientists?

Strange how ayncritus asks a seemingly rhetorical question, then unwittingly answers it with the very next sentence:

There is the additional question, not even mentioned, that birds do not have a diaphragm, but reptiles do. Where has the diaphragm gone? Why has it disappeared, when it functions properly, correctly and effectively in reptiles of today?

As far as the birds are concerned, there is no need for a diaphragm. As quoted above, the air sacs perform the function: The air sacs act as "bellows" to suck air in and blow it out, and also to hold part of the total volume.

Also, here is a very simple answer to another question that seems to be vexing him:

Carl Wieland of 'Answers in Genesis' has written a response to this paper (13), that is generally reasonably restrained, but utterly fallacious. He correctly points out that this analysis does not, in itself, resolve the issue of the steps by which a bellows type lung evolved into the avian flow-through system. His discussion is, however fundamentally flawed in one important respect: his main objection to the evolution of an avian system from a bellows system is that he cannot see how it could happen. This of course is the old canard (a term that is peculiarly well suited to this subject!) of the argument from personal incredulity. Carl cannot conceive of a pathway by which the avian lung could evolve from a bellows arrangement, so of course, in his mind, it cannot have happened. This was the original design argument used by William Paley. It was intellectual gruel then, and it is intellectual gruel now. Carl would have us believe that there is an 'in-principle' barrier to the evolution of 'flow-through' ventilation. (I think Carl means unidirectional flow-through ventilation - he doesn't seem to recognise the distinction between unidirectional and bidirectional flow-through ventilation). Of course, there is no such 'in-principle' barrier and one can think of very obvious routes by which the avian system could develop from a bellows arrangement. The first obvious step in this process, the development of a bidirectional flow-through system with air sacs positioned beyond the lung in the tail end of the trunk is strongly supported by this study. Carl asks 'How could any creature breathe while the in-between stages were evolving, while air was not yet flowing through but no longer going in and out? The answer to this is obvious: it breathes by air flowing thriough the lung bidirectionally - in other words it flows through and goes in and out.

I wonder whether Carl realises that, even in modern birds, there is a mixture of unidirectional flow through the so-called palaeopulmonic bronchi and bidirectional flow through the so-called neopulmonic bronchi.

Ugh, I deal with this all the time at my school. Can you believe as a biomedical student, that in my 400 level biochem class we have a guy who seriously thinks we live in a young earth. It freaking scares me how supposedly educated men and women of science can be so ignorant.

Scales and feathers:

willhud9 wrote:Ugh, I deal with this all the time at my school. Can you believe as a biomedical student, that in my 400 level biochem class we have a guy who seriously thinks we live in a young earth. It freaking scares me how supposedly educated men and women of science can be so ignorant.

All you need is faith ba ba baba da. All you need is faith ba ba bada da. All you need is faith-faith. All you need is faith!

Oldskeptic wrote:

willhud9 wrote:Ugh, I deal with this all the time at my school. Can you believe as a biomedical student, that in my 400 level biochem class we have a guy who seriously thinks we live in a young earth. It freaking scares me how supposedly educated men and women of science can be so ignorant.

All you need is faith ba ba baba da. All you need is faith ba ba bada da. All you need is faith-faith. All you need is faith!

Hey, I like that song. Don't ruin it.

I don't believe it though.

Well it's funny because all one has to do is look at the biochemical properties of a reptile's scale and an avian's feather and you see a remarkable similarity. Both are made up of β-keratin instead of α-keratin. β-keratin is what makes up a bird's beak, talons, and feathers, while reptiles have β-keratin infused within their Stratum corneum (outer most layer of the epidermis) which gives it a hard scaly surface. Truly remarkable.

willhud9 wrote:Well it's funny because all one has to do is look at the biochemical properties of a reptile's scale and an avian's feather and you see a remarkable similarity. Both are made up of β-keratin instead of α-keratin. β-keratin is what makes up a bird's beak, talons, and feathers, while reptiles have β-keratin infused within their Stratum corneum (outer most layer of the epidermis) which gives it a hard scaly surface. Truly remarkable.

Stop making sense. It's not polite and just muddies the water.