I don't see dinosaurs into birds as such a big change, especially since we've discovered in the last decade or so that many dinosaur families were covered in feathers. The only major difference I see is the wings for flight and the pointed beak, one could almost call it micro evolution even, as some dinosaurs even had beak-like bills! And many were small, the smallest adult dinosaur discovered was only 4 inches tall, covered in feathers and probably looked just like our local Indian miner scavenger birds (without the flight or beak).
But I guess the point I should make is that we've found mutant whales with legs, they still have the genes for growing legs but the genes are turned off. Just like birds still have the genes for growing teeth, but are likewise inactivated.
So it's no fairy tale!
Whale ancestors had legs and bird ancestors had teeth
Dinosaurs to Birds?
Some extinct birds, such as
Archaeopteryx, shared quite a few features with some theropods. That raises the question of how one can determine whether a creature is a bird that resembles a dinosaur or a dinosaur that resembles a bird. Feathers had long been accepted as a distinctively avian characteristic because they had never been found on any creature, living or extinct, that was not a bird.[SUP][[/SUP]
22[SUP]][/SUP] The presence of feathers marked a creature as a bird, but one is now told that this is an invalid criterion and that
Protarchaeopteryx and
Caudipteryx were dinosaurs despite the fact they possessed feathers.
It is difficult to accept that the long hand-feathers of
Caudipteryxevolved within (nonavian) Maniraptora. The strong, grasping hands of maniraptorans were an essential part of their weaponry,[SUP][[/SUP]
37[SUP]] [/SUP]but the well-formed feathers attached to
Caudipteryx’s middle finger would prevent the hand from being used as a grasping organ. What possible selective advantage could be bestowed on a cursorial predator by the development of hand-feathers that disable the function of one of its primary weapons?
Since the discovery of
Protarchaeopteryx and
Caudipteryx, two filament-bearing dinosaurs from the Yixian Formation in China (middle Early Cretaceous) have been reported in the formal scientific literature: a quite fragmentary seven-foot-long therizinosaur dubbed
Beipiaosaurus inexpectus [SUP] [[/SUP]
50[SUP]][/SUP] and an eagle-size
dromaeosaurid (mentioned above) dubbed
Sinornithosaurus millenii. [SUP] [[/SUP]
51[SUP]][/SUP] Theropod advocates suggest that these filaments represent an early stage in the development of feathers and thus link theropods to avian ancestry, but this is pure speculation. As Dr. Olson put it in his recent open letter, “[t]he statement [in Sloan 1999] that ‘hollow, hairlike structures characterize protofeathers’ is nonsense considering that protofeathers exist only as a theoretical construct, so that the internal structure of one is even more hypothetical.”
The theropod faithful, undaunted by these issues, claim (in the recent exhibit at National Geographic Society) “there is strong evidence that a wide variety of carnivorous dinosaurs had feathers” and depict
Deinonychus and baby tyrannosaurs as having feathers. Dr. Olson labels the claim “spurious” and says the depictions are “simply imaginary and [have] no place outside of science fiction.”
Too specialized. In all the talk about shared anatomical traits and “sister groups,” it is easy to lose sight of the fact that, even if they were old enough, all known coelurosaurs are too specialized to have been actual ancestors of birds. In other words, they have features believed to have arisen in their lineage after it split from the lineage leading to birds, which features disqualify them as actual ancestors. Thus, after explaining that
Compsognathus could not be ancestral to
Archaeopteryx because of its date and its specialization, Carroll says, “No other adequately known theropod appears to be an appropriate ancestor.”
Similarities overstated. It is not widely known at the popular level, but many of the key characters seen as uniting birds and theropods are disputed. According to Feduccia, these include:
the nature of the pelvis (Martin 1991; Tarsitano 1991), the homology of the digits (Hinchliffe and Hecht 1984; Hinchliffe 1985; Martin 1991; Tarsitano 1991), the nature of the teeth (Martin, Stewart, and Whetstone 1980); Martin 1991), the hallux (Tarsitano and Hecht, 1980; Martin 1991; Feduccia 1993a), the ascending process of the astragalus (Martin, Stewart, and Whetstone 1980; Martin 1991; also see McGowan 1984, 1985 and reply by Martin and Stewart 1985), the pubis (Martin 1983a, 1983b, 1991; Tarsitano 1991; also see Wellnhofer 1985), and even the supposed unique semilunate carpal thought to be shared by
Deinonychus and
Archaeopteryx (and modern birds) (Martin 1991; Tarsitano 1991).[SUP][[/SUP]
95[SUP]][/SUP]
Since the hypothesized relationship of theropods to birds is based on the similarity of certain features, uncertainty about that similarity casts doubt on the hypothesis. There is obviously more art in the interpretation of these fossils than popular presentations would lead one to believe.
Lung questions. John Ruben, an expert in respiratory physiology, concluded from an examination of
Sinosauropteryx “that theropods had the same kind of compartmentalization of lungs, liver, and intestines that you would find in a crocodile”—and not a bird.[SUP][[/SUP]
96[SUP]][/SUP] The thoracic cavity and the abdominal cavity of theropods appear to have been completely separated from each other by the diaphragm, whereas birds have no such separation. In living crocodilians, the function of this separation is to provide an airtight seal between the cavities. Air is drawn into the bellows-type lungs by contraction of the diaphragmatic muscles which creates negative pressure in the thoracic cavity.
One reason this is significant is that, as Ruben argues, “a transition from a crocodilian to a bird lung would be impossible, because the transitional animal would have a life-threatening hernia or hole in its diaphragm.” According to Ruben, this means that if there is a relationship between dinosaurs and birds, “it’s not the linear relationship you see in the museum displays.”
Flight question. A corollary of the theropod theory of bird origins is that flight evolved from the ground up (cursorial theory) rather than from the trees down (arboreal theory). There is, however, no plausible explanation for how this could have occurred. The difficulty is so great that Chatterjee, who supports theropod ancestry, suggested recently that some theropods may have been tree climbers.[SUP][[/SUP]
104[SUP]][/SUP] If they were, they apparently left no evidence of that ability. According to Fastovsky and Weishampel:
It has been argued that perhaps the earliest birds scaled trees, and from that position learned to fly. There is, however, no evidence for an arboreal proto-bird, no evidence for climbing adaptations, and no evidence in the skeleton of any nonavian theropod for arboreal habits.
The idea that birds evolved from dinosaurs remains at best a highly speculative hypothesis. One suspects its popularity has less to do with the evidence for theropod ancestry than with the Darwinian aversion to ancestral vacuums. When paleontologist Hans-Dieter Sues says, “Only dinosaurs are anatomically suited to be the precursors of birds,”[SUP][[/SUP]
118[SUP]][/SUP] he is saying that, when it comes to bird origins, it is dinosaurs or nothing. Since evolutionists are convinced that every taxon arose from some other, “nothing” is not an option. This philosophical predisposition induces them to read lineages into ambiguous data. They compound that error by confusing these interpretive constructs with fact.
One can state the matter no more forcefully than did Storrs Olson in his November 1, 1999 letter to the most prominent scientist at the National Geographic Society. He concluded with the following:
“The idea of feathered dinosaurs and the theropod origin of birds is being actively promulgated by a cadre of zealous scientists in concert with certain editors at Nature and National Geographic who themselves have become outspoken and highly biased proselytizers of the faith. Truth and careful scientific weighing of evidence have been among the first casualties of their program, which is now fast becoming one of the grander scientific hoaxes of our age – the paleontological equivalent of cold fusion. If Sloan’s article is not the crescendo of this fantasia, it is difficult to imagine to what heights it can next be taken. But it is certain that when the folly has run its course and has been fully exposed, National Geographic will unfortunately play a prominent but unenviable role in the book that summarizes the whole sorry episode.”
- On the Alleged Dinosaurian Ancestry of Birds -