Intelligent Design, the best explanation of Origins

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Intelligent Design, the best explanation of Origins » Theory of evolution » No evidence for the evolution of birds, feathers, and flight

No evidence for the evolution of birds, feathers, and flight

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No evidence for the evolution of birds, feathers, and flight

Take flying birds for example; suppose you aren't one, and you want to become one. You'll need a baker's dozen highly specialized systems, including wings, flight feathers, the specialized system which allows flight feathers to pivot so as to open on upstrokes and close to trap air on downstrokes (like a venetian blind), a specialized light bone structure, specialized flow-through design heart and lungs, specialized tail, specialized general balance parameters etc.

For starters, every one of these things would be antifunctional until the day on which the whole thing came together, so that the chances of evolving any of these things by any process resembling evolution (mutations plus selection) would amount to an infinitessimal, i.e. one divided by some gigantic number.

In probability theory, to compute the probability of two things happening at once, you multiply the probabilities together. That says that the likelihood of all these things ever happening, best case, is ten or twelve such infinitessimals multiplied together, i.e. a tenth or twelth-order infinitessimal. The whole history of the universe isn't long enough for that to happen once.

All of that was the best case. In real life, it's even worse than that. In real life, natural selection could not plausibly select for hoped-for functionality, which is what would be required in order to evolve flight feathers on something which could not fly apriori. In real life, all you'd ever get would some sort of a random walk around some starting point, rather than the unidircetional march towards a future requirement which evolution requires.

And the real killer, i.e. the thing which simply kills evolutionism dead, is the following consideration: In real life, assuming you were to somehow miraculously evolve the first feature you'd need to become a flying bird, then by the time another 10,000 generations rolled around and you evolved the second such feature, the first, having been disfunctional/antifunctional all the while, would have DE-EVOLVED and either disappeared altogether or become vestigial.

Now, it would be miraculous if, given all the above, some new kind of complex creature with new organs and a new basic plan for life had ever evolved ONCE.

Evolutionism, however (the Theory of Evolution) requires that this has happened countless billions of times, i.e. an essentially infinite number of absolutely zero probability events.

I ask you: What could be stupider than that?

"Feathers are features unique to birds, and there are no known intermediate structures between reptilian scales and feathers. Notwithstanding speculations on the nature of the elongated scales found on such forms as Longisquama ... as being featherlike structures, there is simply no demonstrable evidence that they in fact are. They are very interesting, highly modified and elongated reptilian scales, and are not incipient feathers."

Feduccia, Alan (1985) "On Why Dinosaurs Lacked Feathers The Beginning of Birds Eichstatt, West Germany: Jura Mus

As one Columbia University biologist put it, “ . . . we lack completely fossils of all intermediate stages between reptilian scales and the most primitive feather.”

Oregon State University, “Discovery raises new doubts about dinosaur-bird links,” June 9th, 2009,

The origin of birds has always been a major problem for Darwinism, and even today little agreement about the evolution of birds exists. One of the most difficult issues related to bird evolution is the evolution of feathers. Feathers are complex, designed structures required for flight, and are today found only on birds. A literature review on the evolution of bird feathers showed that even though feathers are found back as far as the Cretaceous, including many well-preserved samples in amber, the fossil record reveals a complete absence of evidence for feather evolution.

The beautiful Illustra documentary Flight: The Genius of Birds gives a much more elegant and satisfying explanation for flight, because it doesn’t gloss over the details, but accounts for all the traits needed for powered flight: efficient one-way lungs, efficient digestive and excretory systems, the beautifully engineered flight muscles that provide a compact center of gravity, the hollow bones, the navigation systems, the sensory components (able not only to see details from the air but to sense the magnetic field), the exquisite design of feathers, and the behaviors that allow birds to take advantage of air currents, including the lift from other birds in formation flight (1/16/14).  The integrated systems that allow an eagle to pick a fish out of a lake, a hummingbird (12/05/13) to hover in mid-air sucking its food out of a flower with a specialized nectar-trapping tongue, or a snowy egret with its large, elegant wings to fly between tree limbs without hitting them, are explained by appealing to what we know in our universal experience about complex functional systems.  Intelligent design is a known “vera causa” (true cause) that can account for the observations.

Evolution, by contrast, comes up empty looking for a true cause for flight (7/30/13).  Never do we see blind, unguided processes leading to complex functional systems with integrated parts contributing to the overall design goal.  Intelligent design is, therefore, the best scientific explanation in contrast to the storytelling from the Darwin camp (9/30/13).  The Tweety Rex fable looks downright silly by comparison.  With its high perhapsimaybecouldness index, its stretchable rates of evolution (a clear ad hoc theory rescue device), and its copious use of magic words (emerged, arose, developed, appeared), it reduces to “birds evolved because they evolved.”  If the public were allowed to hear the two explanations side by side, there would be no contest.  Darwin’s flightless DODO birds would go running out of the auditorium in shame.

Consider feathers, which come in more than one form. Down feathers serve for insulation and are not that much different from hair or fur. A proponent of evolution could talk about fur mutating into down feathers and not sound totally stupid. But flight feathers are so totally different from down feathers that you'd need TWO mutations to get to them i.e. one mutation to get from fur to down feathers and then another to get from down feathers to flight feathers.

Flight feathers are asymmetric (one side shorter than other) and they pivot so as to open and let air pass through on upstrokes and close again on down-strokes and a the short side is the locking side. Flight feathers involve a complex system of barbules and hooks  to create the strength needed to bear weight. Down feathers don't have any of that stuff.

The question is, what kind of a mutation would cause down feathers to mutate into flight feathers ONLY ON THE CREATURE'S ARMS where they will be needed after other mutations turn those arms into wings??

What Is the Evidence for Feathers Before Flight?

Feathers are branched structures consisting of β-keratin—a rigid protein material formed by pleated β sheets—with a hollow central shaft. They are strikingly different from other forms of vertebrate integument such as scales, skin, and hair. Until recently, evolutionary hypotheses envisioned their origin through elongation of broad, flat scales driven by selection for aerial locomotion such as gliding or flapping flight. Over the course of the past two decades, fossil discoveries, especially from northeast China, have revealed that the early precursors of feathers were filament-like rather than expanded scales and that branched pinnate feathers of modern aspect predate the origin of active flight.

The Chinese deposits provide one such unique snapshot, where over a thousand specimens with fine details of soft tissues such as feathers, hair, and skin are preserved in ash-rich lake deposits ranging from the Late Jurassic (∼150 million years ago) to the Early Cretaceous (∼120 million years ago). Fossils from these deposits have revealed that dinosaurs that were inferred from bone characteristics to be closely related to living birds also share more features of feather structure.

Oh, wow, this article is so classic of the evolutionary genre, it’s a virtual gift to creationists.  Aside from the obvious evidential conclusion that dinosaur-to-bird evolution is a myth, Clarke used all the evolutionary tricks of the trade we’ve been pointing out in the Darwin lit for 12 years now: the Stuff Happens law, just-so stories, shielding complex changes in words like “novelty” and “innovation,” promissory notes, the coulda-woulda-shoulda habit, embedding evolution in terms like “protofeathers,” the convergence concoction, using passive verbs and subjunctive mood as covers for ignorance, composite explanations, punk eek, incredible stasis, ghost lineages, “more research is needed,” job security for storytellers, glossing over soft tissue in supposedly ancient material, tidbits of Lamarck and Haeckel as needed when gradualism doesn’t work, forcing uncooperative data into prefab scenarios, parading naked Emperor Charlie in public, sacrificing brains at his shrine – everything.  Hardly a sentence of this article is devoid of fallacies masquerading as science.

We hope you caught these things before the commentary began.  If not, you need Creation-Evolution Headlines as a deprogramming course.  Bookmark this site and come for your daily therapy.  Since Ken Dial made an off-camera appearance, we like all beginners to get the shock treatment in our commentary from 12/22/03 – the first time (now a decade ago, still cited favorably by Darwinists) the Montana drunkard-on-Darwine presented living partridge family chicks as possible props to an evolutionary tale.  Read that color commentary now; know the tricks, and you won’t be fooled again.

The Evolution of Feathers: A Major Problem for Darwinism

Even though fossil impressions of feathers are abundant in the fossil record, and much has been written speculating on how scale-to-feather evolution could have occurred, not a shred of fossil or other evidence has ever been found to support the scale-to-feather evolution theory.1,23 In the words of Prum, understanding ‘the evolutionary origin of feathers has been constrained by the lack of any known ancestral feather morphologies or structural antecedents’.41

The evidence supports Klotz’s early conclusion that the ‘origin of feathers is still a real problem’ for Darwinism, and all contemporary theories of feather origin are hypothetical ideas that ‘can only be characterized as judicious speculation’.75 In short, nothing has changed since Regal stated ‘although most textbooks include some sort of speculation on the evolutionary origin of feathers … [a] morass of contradictory theories and muddy thinking … occurs in … much of the literature on this subject’.31

Although much speculation and major disagreements exist on how feathers ‘could have’ evolved, all existing theories are ‘just-so stories’, unsupported by fossil or historical evidence. The profound evolutionary enigma of feathers noted by Darwin76 and Heilmann77 remains, even today. The lack of evidence for feather evolution is not only a major problem for Darwinism, but the design and function of feathers provides evidence for both intelligent design and irreducible complexity. Flight and feathers are indeed a ‘miracle’.78 Feather evolution is related to the question of bird evolution.

Periodically, new bird fossils are found, but most of them have been of little or no use as evidence of bird evolution, and the few claimed examples typically generate much debate. For instance, Feduccia concluded that one recent find, known as Apsaravis, contributes little

   ‘… to our understanding of avian evolution, and its lack of a clear relationship with any kind of modern bird makes its significance ambiguous. If Apsaravis is not related to any modern ornithurine, how can it tell us anything important about the evolutionary questions raised by [its discoverers] Norell and Clarke?’79

The latest discovery of feathers on the birdlike, turkey-sized ‘theropods’ Caudipteryx and Protarchaeopteryx indicate that they are flightless birds. Much debate exists about this and related finds.80 Some consider these animals to be birdlike dinosaurs, or other dinosaur-like, flightless birds that have lost their full flight plumage (or never developed it). Conclusions on these finds will require much more study, and yet already have produced much debate and controversy.

Much disagreement still exists about Archaeopteryx, a discovery now around 150 years old. Likewise, the place in evolution, if any, of the recent finds may never be settled. Many of these finds are from a province of China, and already one find from this area has proven to be a hoax. Consequently, much more study is necessary to determine the value of these finds. So far, none of these finds challenges the conclusions presented in this paper, and early study of these finds has strongly supported the findings reviewed here.

In conclusion, we agree with Brush: ‘Uncountable numbers of words have been written in attempts to … reconstruct the primitive feather and explain why feathers evolved’.56 So far, all of these attempts have not only failed, but also have led to the conclusion that how feathers ‘arose initially, presumably from reptilian scales, defies analysis’.81


Mutation predicts 40 million years of fly wing evolution

This is remarkable when a paper in Nature magazine openly throws the towel and admits :

No evidence for the evolution of birds, feathers, and flight Cfz_da10

Our finding of striking similarities among mutational, genetic and
among-species variation coupled with a low rate of evolution are not readily explained by any of the available models of evolution. This is an important challenge for evolutionary theorists.

What is remarkable as well, is the misleading title of the paper....

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Explanatory History of the Origin of Feathers

However, because of the lack of knowledge about the roles and ecological relationships of protofeathers and of the most primitive feathers, it is not possible to test strongly either of these theories, or others as proposed in this symposium, against objective empirical observations to determine which is falsified or is the most probable.

Historical-narrative evolutionary explanations for the origin and further evolution of avian feathers involve two steps. The first phase reconstructs a series of probable morphological changes from a reptilian scale to the primitive feather. The second deduces possible functions and biological roles of the features and feasible selective demands on these features at all stages in its evolution. The best explanation for the evolutionary origin of feathers would be one consistent with historical-narrative evolutionary explanations for the origin and further evolution of other features in the history of birds. Feathers of Recent birds have a number of functions and biological roles, and it is difficult to ascertain which of these functions and roles were involved in feather origin. Two major rival published theories are based on the roles of feathers in insulating the body against heat loss and in providing an aerodynamic surface for flight. However, because of the lack of knowledge about the roles and ecological relationships of protofeathers and of the most primitive feathers, it is not possible to test strongly either of these theories, or others as proposed in this symposium, against objective empirical observations to determine which is falsified or is the most probable. Finally it is argued that test of historical-narrative evolutionary explanations, including classifications and phylogenies, is generally difficult to impossible because of the lack of the necessary objective empirical observations.

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In order for an organism to fly, its entire body would have to evolve to a state where it's light enough for wings to support it. You need wings that are light enough yet strong enough to support the body. You need muscles powerful enough to flap those appendages quickly enough (70 beats per second in the case of a hummingbird!) for a sustained period of time. The development must be symetrical, because having just one wing does no good. If wings evolved from legs, how well could an animal evade predators during the in-between stages where the legs are too long and flimsy to walk on, but not yet light enough to enable flight? Natural selection will take its toll on anything that even comes close. All this assumes the wing has evolved into the shape of a workable airfoil that actually flies in the first place! The list goes on and on and on. I'm sorry, but the evolutionist's magic wand of millions of years is still far too short for anything as complex as flight to develop as a result of purely random changes to DNA. The ability for animals to fly is one of the reasons I find evolution absolutely implausible as an explanation of how life developed.

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The evolution of insect wings and subsequent flight is a concept impossible for evolutionists to explain. Insects are the ultimate flying machines—even humans’ most state-of-the-art aircraft cannot match the flight of insects. There is no way that the insects could have gradually evolved flight, nor is there fossil evidence of any intermediate species of insect between flying and non-flying insects. The fossil record indicates that if, in fact, flight evolved in insects, then it did so very rapidly. However, such a rapid, complex evolutionary advancement is impossible, and even goes against evolutionary theory. All of the evidence exemplifies elaborate design, and documents that everything was created fully functional in the beginning. All evidence points toward the intelligent design of insect flight—its form, function, and creation.

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1. There is no observational evidence to support the claim dinosaurs evolved into birds.
2. Evolutionists commonly resort to artistic drawings in textbooks rather than real evidence.
3. Evolutionists have produced a history of false claims.
4. The scientific evidence supports dinosaurs and birds lived at the same time just as the Bible teaches.

Origin of Avian Flight

As a rule, a scientific explanation should avoid several common fallacies. One is the post-hoc fallacy: claiming that A caused B simply because A preceded B. Another fallacy is ad hoc reasoning: multiplying auxiliary hypotheses to maintain one's favored hypothesis. A third fallacy is begging the question. For instance, if an ID proponent were to state in a debate with an evolutionist about the origin of flight, "Because birds are designed, its flight systems must also have been designed," that would beg the question at issue. An even worse error is to ignore or arbitrarily "rule out of bounds" alternative explanations.

Some of the recent Darwinian accounts for the origin of flight commit all these fallacies. For instance, a news item from the University of Southampton is titled, "Dinosaur wind tunnel test provides new insight into the evolution of bird flight." This completely ignores all non-evolutionary explanations from the outset. All claims thereafter are doomed to beg the question of evolution.

In the article itself, we see the other fallacies fly by: one of the professors who put a model of the four-winged dinosaur Microraptor gui into a wind tunnel to test its aerodynamics committed several of the fallacies in these statements:

"Significant to the evolution of flight, we show that Microraptor did not require a sophisticated, 'modern' wing morphology to undertake effective glides, as the high-lift coefficient regime is less dependent upon detail of wing morphology."

"This is consistent with the fossil record, and also with the hypothesis that symmetric 'flight' feathers first evolved in dinosaurs for non-aerodynamic functions, later being adapted to form aerodynamically capable surfaces." (Emphasis added.)

But the issue at hand is the origin of powered flight, not just gliding. As shown so beautifully in the Flight film,

true powered flight by any heavier-than-air vehicle (whether avian or artificial) requires a complex suite of interacting systems.

The professor begs the question that gliding will evolve into powered flight. He commits the post-hoc fallacy by assuming that feathers "first evolved... for non-aerodynamic functions" then were later adapted for flight. And he commits ad hoc reasoning by invoking some unknown function for feathers in dinosaurs. (See also his team's paper in Nature Communications.)

What about those feathers on dinosaurs? Various "integumentary structures" have been found associated with fossils of some dinosaurs, but assuming they "evolved" into true flight feathers would commit the post-hoc fallacy again, besides begging the question that evolution "adapted" them for flight later.

Microraptor itself, with abundant feathers of modern aspect on four wings, is dated later than Archaeopteryx, a powered flyer. One fossil M. gui specimen was even found with a bird in its stomach, PNAS reported. Without getting into the weeds about fossils of feathers, since we want to compare explanations for the origin of powered flight, suffice it to say the record is confusing, even to Darwinian evolutionists, as Julia Clarke wrote in Science a few months ago:

Evidence is thus accruing for the function of early pinnate feathers in sexual selection, but there is little consensus on shifts in feather function associated with the evolution of flight. Reconstruction of ancestral conditions for the bird lineage requires consensus on the evolutionary relationships of key species. These species differ in feather shape as well as in their organization and layering on the forelimb and hind limb. Whether observed differences can presently speak to a gliding or flapping origin for flight is debated.

No wonder the film said that evolutionary theories about the origin of flight are highly controversial.

In its coverage of the Microraptor wind-tunnel experiment, New Scientist showed its propensity for ad-hoc reasoning: "plumage might not have evolved for flight but may instead have been a key aspect of sexual-selection displays."
More question-begging, alternative-ignoring, ad-hoc reasoning can be seen in a news item from the University of Oxford about bird tails. The article claims that shortened tails "gave early birds a leg up" in evolution -- "as soon as this happened it freed up their legs to evolve to become highly versatile and adaptable tools that opened up new ecological niches." Since this occurred after "birds had already evolved powered flight," though, it's irrelevant to the question of the origin of powered flight. It just shows the propensity by some evolutionists to beg questions and ignore alternatives.

Perhaps the most bizarre recent case of question-begging, ad-hoc reasoning is an item from McGill University with a Kipling-style just-so story title, "How birds got their wings." It basically claims that if you allow birds to evolve flight, they will:

This limb scaling changed, however, at the origin of birds, when both the forelimbs and hind limbs underwent a dramatic decoupling from body size. This change may have been critical in allowing early birds to evolve flight, and then to exploit the forest canopy, the authors conclude....

As forelimbs lengthened, they became long enough to serve as an airfoil, allowing for the evolution of powered flight....

Our findings suggest that the limb lengths of birds had to be dissociated from general body size before they could radiate so successfully. It may be that this fact is what allowed them to become more than just another lineage of maniraptorans and led them to expand to the wide range of limb shapes and sizes present in today's birds.

Needless to say, this explanation is unsatisfying. If changing limb ratios is all it takes to "allow" animals to fly, why didn't pigs try that? What "allowed" the simultaneous changes to the avian lung, flight feathers, and navigation? Why did the bones become hollow? How were the digestive, muscular, and respiratory systems overhauled, and how did they have any fitness value before powered flight emerged?

The ID Alternative

In Flight, Paul Nelson seeks the "vera causa" (true cause) of avian flight.

Now in the case of the origin of flight, we have a complex function, with all the associated anatomy and behavior and so forth, and the question we really should be asking is, what is the cause that is sufficient to bring this about? What is the vera causa of avian flight?

Nelson, Tim Standish and Ann Gauger consider the alternative of evolution or any other explanation that requires naturalism, resulting in just the "appearance of design" without actual design. Then they review all the systems that make flight possible, from feathers to "the most efficient respiratory system in the animal kingdom." Standish says:

Obviously, you're coordinating many, many, many different systems that have to be all exactly right for the bird to fly. And the more systems and component parts that are involved, the more challenging it is to explain how all of them came together so precisely in a bird.

Here's how Nelson sums up the ID explanation:

Here's the bottom line. You look at the anatomy of a bird, its behavior, its metabolism, the structure of its feathers, the structure of its muscles and so forth -- these are multiple independent points in a complex space, out of which flight emerges. And I think from a biological standpoint, to fly at all requires a cause that is able to visualize a distant functional endpoint, and bring together necessary to achieve that endpoint. Uniquely, and universally in our experience, only intelligence is capable of that kind of causal process.

Standish adds:

An engineered system is the product of a mind that anticipated a problem and figured out a multi-step way of addressing that problem. In birds you see exactly that kind of process. I believe intelligent design is the best explanation for avian flight, because it's the best explanation for every other kind of flight that we see. So why would I suddenly change the rules when I go from a 747 to a pigeon? ... They're engineering marvels. They're works of art. We know where engineered things come from. We know where works of art come from. So why would we attribute a bird to anything other than intelligence or mind?

The ID explanation, therefore, rests on known causes from our uniform experience. An explanation that avoids ad-hoc reasoning, the post-hoc fallacy, and question-begging arguments -- one that explores rather than ignores alternatives -- one that seeks the vera causa from known causes sufficient to bring about a phenomenon -- that explanation should be the one judged scientifically the best.

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Insects require a highly specialized flight apparatus. Biomechanical prerequisites for insect flight include extremely powerful muscles in the thorax to generate force, axillary apparatus (the “shoulders” of the insects) to transfer force, and the wings themselves to convert force into flight. Most insects can perform a variety of aerial feats, because they possess a direct as well as an indirect muscular system. Direct muscles are attached directly to the wings, indirect muscles are not. The dorsoventral (midline on the back—MV) muscles contract to raise the wings. The longitudinal muscles contract to lower the wings. When the dorsoventral muscles contract, the tergum (back segments—MV) is lowered and the wings rotate about the other hinges and rise. When the longitudinal muscles contract, tergum is forced up again and the wings rotate in the opposite sense about the outer hinges. Additionally, insects are able to flap their wings in figure-eight patterns because of their dorsoventral muscles that are attached to the wing base.

As a result of their unique musculature, insects can beat their wings much faster than birds, which possess a direct muscular system. Humans also possess a direct muscular system. Break from your reading for a moment and try something. Extend your arms out to your sides parallel with your shoulders. Now flap your arms as fast as you can for five seconds. I would be impressed if you could flap twenty times. Insects can beat their wings up to 1,000 times in one second. This feat is a result of their unique muscular system as well as the unique design of the insect’s brain. The muscles themselves require few orders from the brain. When a human flaps his arms, his brain has to command each stroke on each side of his body. The insect’s brain does not have to think about every wing beat; it only needs to instruct the wings to begin or stop flapping.

When you flapped your arms, you probably not only looked silly to those around you, but you probably also became tired very quickly. Now imagine flapping your arms 200 times as fast! This would cause even the strongest of humans to collapse from exhaustion. The metabolic rate of all flying creatures is extremely high in relation to land-dwelling creatures. Dudley even found himself confessing: “Flight is energetically very costly, and the metabolism of winged insects represents an extreme of physiological design among all animals” (Dudley, 2000, emp. added). Insects do not have a central breathing organ (like lungs); instead, oxygen is supplied to the flight muscles via the insect’s tracheal respiratory system. Insects do not breathe as humans do. They do not pull air in, but simply diffuse gases that pass through the tracheal respiratory system. This system comprises up to 10 percent of the insect’s body mass. The whole body is equipped for flying, yet many scientists purport that it is an evolutionary accident that they are able to fly.

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Feathers Not Flying Over New Dinosaur Fossil

There are three general problems with claims of feathered dinosaur fossils: (1) they aren't feathered (i.e., they have dinofuzz, a wispy hair-like feature that isn't the same as feathers), or (2) they aren't dinosaurs (i.e., they are secondarily flightless birds and not dinosaurs at all), or (3) they aren't fossils (i.e., they're one of the examples of fake fossils that's appeared like the infamous Archaeoraptor). A new fossil ornithischian dinosaur reported inScience is said to have had "avianlike feathers," but some critics think it belongs in category (1) -- i.e., it wasn't feathered at all. The paper on the fossil inScience states:

Here we report a new ornithischian dinosaur, Kulindadromeus zabaikalicus, with diverse epidermal appendages, including grouped filaments that we interpret as avianlike feathers.

Yet according to an article in National Geographic, "Fluffy Dinosaur Raises Questions About the Origin of Dinofuzz," we can't establish that these are feathers:

In terms of typical dinosaur tubercles, Kulindadromeus had hexagonal scales on its lower legs, rounded scales around the hand and ankle, and rows of large scales along the tail. But the fossils also preserved a trio of feathery structures. Single filaments surrounded the dinosaur's head, torso, and back, while the dinosaur's upper arms and legs were covered in multi-filament plumes and the dinosaur's lower leg sported "ribbon-shaped elements" that have not been seen in any other species so far.

The question is whether these fluffy structures are true feathers or fluffy imitations. This has major implications for when true feathers and their immediate forerunners evolved in dinosaurs. If the dinofuzz on Kulindadromeus really is equivalent to that borne by theropods like Sinosauropteryx, then the beginnings of feathers probably coincided with the origin of dinosaurs. If the structures are superficially the same, but not truly equivalent, then feather-like structures either evolved more than once or diverged from some earlier, as-yet-unseen type of integument.
For the moment, there's still no way to distinguish between these alternative scenarios. At a basic anatomical level paleontologists have yet to discern whether the structures on Psittacosaurus ,Tianyulong , and Kulindadromeus can truly be called feathers. Not to mention the need for better fossils of older dinosaurs, close to where the major lineages split, to follow feather origins, as well as a more refined understanding of the circumstances under which fluff, fuzz, and bristles are likely to be preserved.

Did you note the statement in the last paragraph? "At a basic anatomical level paleontologists have yet to discern whether the structures on Psittacosaurus ,Tianyulong , and Kulindadromeus can truly be called feathers." Looking at the diagram from the paper, they sure don't look much like feathers:

I see wispy hair-like structures. I see dinofuzz. But I don't see feathers. A prominent critic writing in National Geographic says much the same. Yet these structures are being unapologetically called "feathers" in Science. It seems to me the theory is getting ahead of the data.

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Functional roles of Aves class-specific cis-regulatory elements on macroevolution of bird-specific features

Unlike microevolutionary processes, little is known about the genetic basis of macroevolutionary processes. One of these magnificent examples is the transition from non-avian dinosaurs to birds that has created numerous evolutionary innovations such as self-powered flight and its associated wings with flight feathers. By analysing 48 bird genomes, we identified millions of avian-specific highly conserved elements (ASHCEs) that predominantly (>99%) reside in non-coding regions. Many ASHCEs show differential histone modifications that may participate in regulation of limb development. Comparative embryonic gene expression analyses across tetrapod species suggest ASHCE-associated genes have unique roles in developing avian limbs. In particular, we demonstrate how the ASHCE driven avian-specific expression of gene Sim1 driven by ASHCE may be associated with the evolution and development of flight feathers. Together, these findings demonstrate regulatory roles of ASHCEs in the creation of avian-specific traits, and further highlight the importance of cis-regulatory rewiring during macroevolutionary changes.

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Axis Specification and the Avian “Organizer”

As a consequence of the sequence in which the head endomesoderm and notochord are established, gastrulating avian (and mammalian) embryos exhibit a distinct anteriorto- posterior gradient. While cells of the posterior portions of the embryo are still part of a primitive streak and entering inside the embryo, cells at the anterior end are already starting to form organs. For the next several days, the anterior end of the embryo is more advanced in its development (having had a “head start,” if you will) than the posterior end. Although the formation of the chick body axes is accomplished during gastrulation, axis specification begins earlier, during the cleavage stage

The role of gravity and the posterior marginal zone PMZ 
The conversion of the radially symmetrical blastoderm into a bilaterally symmetrical structure appears to be determined by gravity. As the ovum passes through the hen’s reproductive tract, it is rotated for about 20 hours in the shell gland. This spinning, at a rate of 15 revolutions per hour, shifts the yolk such that its lighter components (probably containing stored maternal determinants for development) lie beneath one side of the blastoderm. This imbalance tips up one end of the blastoderm, and that end becomes the posterior marginal zone, where primitive streak formation begins 

No evidence for the evolution of birds, feathers, and flight QGrrLKj
Specification of the chick anterior-posterior axis by gravity.
(A) Rotation in the shell gland results in (B) the lighter components of the yolk pushing up one side of the blastoderm. (C) This more elevated region becomes the posterior of the embryo.

It is not known what interactions cause this specific portion of the blastoderm to become the PMZ. Early on, the ability to initiate a primitive streak is found throughout the marginal zone; if the blastoderm is separated into parts, each with its own marginal zone, each part will form its own primitive streak. However, once the PMZ has formed, it controls the other regions of the margin. Not only do the cells of the PMZ initiate gastrulation, they also prevent
other regions of the margin from forming their own primitive streaks. It now seems apparent that the PMZ contains cells that act as the equivalent of the amphibian Nieuwkoop center. When placed in the anterior region of the marginal zone, a graft of PMZ tissue (posterior to and including Koller’s sickle) is able to induce a primitive streak and Hensen’s node without contributing cells to either structure. Current evidence suggests that the entire marginal zone produces Wnt8c (capable of inducing the accumulation of β-catenin) and that, like the amphibian Nieuwkoop center, the PMZ cells secrete Vg1, a member of the TGF-β family.

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