Evolution

Here is a response to my opponent' claims to a " very complete set of bird-reptile fossils". Birds to Dinosaurs According to many evolutionists today, dinosaurs are really not extinct but rather are feeding at our bird feeders even as we speak. For many evolutionists, it would seem, birds simply are dinosaurs. Evolutionists now agree that birds are related in some way to theropod dinosaurs (bipedal meat-eating dinosaurs). The view has gained in popularity since 1970, when John Ostrom discovered a rather “bird-like” early Cretaceous theropod dinosaur called Deinonychus. One of the main reasons that Deinonychus and other similar theropod dinosaurs seemed to be plausible ancestors to birds is that, like birds, these creatures walked solely on their hind legs and have only three digits on their hands. But as we shall see, there are many problems with transforming any dinosaur, and particularly a theropod, into a bird. Problems with Dinosaurs Evolving into Birds Warm-blooded vs. cold-blooded Seemingly forgotten in all the claims that birds are essentially dinosaurs is the fact that dinosaurs are reptiles. There are many differences between birds and reptiles, including the fact that (with precious few exceptions) living reptiles are cold-blooded creatures, while birds and mammals are warm-blooded. Indeed, even compared to most mammals, birds have exceptionally high body temperatures resulting from a high metabolic rate. The difference between cold- and warm-blooded animals isn’t simply in the relative temperature of the blood but rather in their ability to maintain a constant body core temperature. Thus, warm-blooded animals such as birds and mammals have internal physiological mechanisms to maintain an essentially constant body temperature; they are more properly called “endothermic.” In contrast, reptiles have a varying body temperature influenced by their surrounding environment and are called “ectothermic.” An ectothermic animal can adjust its body temperature behaviorally (e.g., moving between shade and sun), even achieving higher body temperature than a so-called warm-blooded animal, but this is done by outside factors. In an effort to make the evolution of dinosaurs into birds seem more plausible, some evolutionists have argued that dinosaurs were also endothermic,[1] but there is no clear evidence for this.[2] One of the lines of evidence for endothermic dinosaurs is based on the microscopic structure of dinosaur bones. Fossil dinosaur bones have been found containing special microscopic structures called osteons (or Haversian systems). Osteons are complex concentric layers of bone surrounding blood vessels in areas where the bone is dense. This arrangement is assumed by some to be unique to endothermic animals and thus evidence that dinosaurs are endothermic, but such is not the case. Larger vertebrates (whether reptiles, birds, or mammals) may also have this type of bone. Even tuna fish have osteonal bone in their vertebral arches. Alan Feduccia, an expert on birds and their evolution, has concluded that “there has never been, nor is there now, any evidence that dinosaurs were endothermic.”[3] Feduccia says that despite the lack of evidence “many authors have tried to make specimens conform to the hot-blooded theropod dogma.” Avian vs. reptilian lung One of the most distinctive features of birds is their lungs. Bird lungs are small in size and nearly rigid, but they are, nevertheless, highly efficient to meet the high metabolic needs of flight. Bird respiration involves a unique “flow-through ventilation” into a set of nine interconnecting flexible air sacs sandwiched between muscles and under the skin. The air sacs contain few blood vessels and do not take part in oxygen exchange, but rather function like bellows to move air through the lungs. The air sacs permit a unidirectional flow of air through the lungs resulting in higher oxygen content than is possible with the bidirectional air flow through the lungs of reptiles and mammals. The air flow moves through the same tubes at different times both into and out of the lungs of reptiles and mammals, and this results in a mixture of oxygen-rich air with oxygen-depleted air (air that has been in the lungs for awhile). The unidirectional flow through bird lungs not only permits more oxygen to diffuse into the blood but also keeps the volume of air in the lungs nearly constant, a requirement for maintaining a level flight path. If theropod dinosaurs are the ancestors of birds, one might expect to find evidence of an avian-type lung in such dinosaurs. While fossils generally do not preserve soft tissue such as lungs, a very fine theropod dinosaur fossil (Sinosauropteryx) has been found in which the outline of the visceral cavity has been well preserved. The evidence clearly indicates that this theropod had lung and respiratory mechanics similar to that of a crocodile—not a bird.[4] Specifically, there was evidence of a diaphragm-like muscle separating the lung from the liver, much as you see in modern crocodiles (birds lack a diaphragm). These observations suggest that this theropod was similar to an ectothermic reptile, not an endothermic bird. Origin of Feathers Feathers have long been considered to be unique to birds. . Since most evolutionists are certain that birds evolved from dinosaurs (or at least are closely related to them), there has been an intense effort to find dinosaur fossils that show some suggestion of feathers or “protofeathers.” With such observer bias, one must be skeptical of recent widely publicized reports of feathered dinosaurs. Dinosaurs are reptiles, and so it is not surprising that fossil evidence has shown them to have a scaly skin typical of reptiles. For example, a recently discovered well-preserved specimen of Compsognathus (a small theropod dinosaur of the type believed to be most closely related to birds) showed unmistakable evidence of scales but alas—no feathers.[5] Still, there have been many claims of feathered dinosaurs, particularly from fossils found in Liaoning province in northeastern China.[6] The earliest feathered dinosaur from this source is the very unbird-like dinosaur Sinosauropteryx, which lacks any evidence of structures that could be shown to be feather-like.[7] Structures described as “protofeathers” in the dinosaur fossils Sinosauropteryx and Sinithosaurus are filamentous and sometimes have interlaced structures bearing no obvious resemblance to feathers. It now appears likely that these filaments (often referred to as “dino-fuzz”) are actually connective tissue fibers (collagen) found in the deep dermal layer of the skin. Feduccia laments that “the major and most worrying problem of the feathered dinosaur hypothesis is that the integumental structures have been homologized with avian feathers on the basis of anatomically and paleontologically unsound and misleading information.”[8] Complicating matters even further is the fact that true birds have been found among the Liaoning province fossils in the same layers as their presumed dinosaur ancestors. The obvious bird fossil Confuciusornis sanctus, for example, has long slender tail feathers resembling those of a modern scissor-tail flycatcher. Two taxa (Caudipteryx andProtarchaeopteryx) that were thought to be dinosaurs with true feathers are now generally conceded to be flightless birds.[9] Thus far, the only obvious dinosaur fossil with obvious feathers that was “found” is Archaeoraptor liaoningensis. This so-called definitive feathered dinosaur was reported with much fanfare in the November 1999 issue of National Geographic but has since been shown to be a fraud. Conclusion Having a true bird appear before alleged feathered dinosaurs, no mechanism to change scales into feathers, no mechanism to change a reptilian lung into an avian lung, and no legitimate dinosaurs found with feathers are all good indications that dinosaurs didn’t turn into birds. Chicken eaters around the world can rest easy-they are not eating mutant dinosaurs!MacroevolutionIt was a poor choice of words to ask you to show me an example of a fly giving birth to a elephant. Macro evolution would be when one kind of animal evolved into a new kind which in most cases requires the addition of genetic information. There is no process of mutation that adds genetic information. To even think that genetic information can be added through any process is ludicrous! Evolutionist QuoteIf so many transitional fossils have been found name one watertight missing link. Side Notes-If evolution is backed by science find a source that isn't an athiest blog (www.talkorigins.org)-Which evolved first the heart or the blood?Sources1.R.T. Bakker, Dinosaur renaissance, Scientific American 232:58–78, 1975.2.A. Feduccia, Dinosaurs as reptiles, Evolution27:166–169,1973; A. Feduccia, The Origin and Evolution of Birds, 2nd Ed., Yale University Press, New Haven, Connecticut, 1999.3.N.R. Geist and T.D. Jones, Juvenile skeletal structure and the reproduction habits of dinosaurs, Science272:712–714,1996.4.A. Feduccia, T. Lingham-Soliar, and J.R. Hinchliffe, Do feathered dinosaurs exist? Testing the hypothesis on neontological and paleontological evidence, Journal of Morphology266:125–166, 2005.5.Feduccia et al., 2005.6.J.A. Ruben, T.D. Jones, N.R. Geist, and W.J. Hillenius, Lung structure and ventilation in dinosaurs and early birds, Science278:1267–1270, 1997.7.U.B. Gohlich and L.M. Chiappe, A new carnivorous dinosaur from the late Jurassic Solnhofen archipelago, Nature440:329–332, 2006.8.P.J. Chen, Z.M. Dong, and S.N. Zheng, An exceptionally well-preserved theropod dinosaur from the Yixian formation of China, Nature391:147–152,1998; X. Xu, X.Wang, and X. Wu, A dromaeosaurid dinosaur with a filamentous integument from the Yixian formation of China, Nature401:262–266, 1999; P.J. Currie and P.J. Chen, Anatomy of Sinosauropteryx prima from Liaoning, northeastern China, Can. J. Earth Sci. 38:1705–1727, 2001.9.Feduccia et al., 2005.