Selections from The Evolution of Dinosaurs: Much Conjecture, Little Evidence, by Jerry Bergman.
Marko's Executive Summary: Jerry Bergman shows how the many theories of where species of individual dinosaurs came from are all unconstrained by fossil evidence. Instead, mainstream scientists rely on morphological comparisons and conjecture. Consequently, the imaginations of Darwinists are allowed great freedom in developing hypotheses.
Scientists such as Fastovsky and Weishampel (2005) have made extensive study of the fossil record, and have reached the conclusion that the likelihood of finding an ancestor in fossil form for of any of the 400-700 dinosaurs species "is nil". So evolutionists admit they are stuck...
Evolutionists admit that evidence is limited and there continue to be many disagreements in the field of dinosaur phylogeny. These disagreements are to the degree that it calls into question the entire basis of dinosaur macroevolution!
(This review and article digest is by Marko Malyj, of the article published in Creation Research Society Quarterly Journal, Volume 46, Number 2, Fall, 2009, at http://www.creationresearch.org/crsq/articles/46/46_2/CRSQ%20Fall%2009%20Bergman.pdf)
Introduction
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| Coelophysis model demonstrating supposed canibalistic behavior |
The study of dinosaurs is an ideal area to evaluate evolution because an enormous amount of excellent fossil evidence exists. Since abundant fossil evidence exists, if dinosaurs evolved from some primitive precursor, good fossil evidence for their evolution from their earlier ancestors should have been uncovered by now. However, the extant fossil evidence does not support their evolution from lower forms of life. In spite of the abundant fossil record, our “knowledge of dinosaurs is very fragmentary and much that has been written remains speculation,” and “many authors have failed to differentiate between speculation and fact” (Croft, 1982, p. 9).
Dinosaur Taxonomy
Dinosaurs were all terrestrial reptiles—members of the archosauria clade that had scaly skin and hatched their young from eggs. The archosauria (ancient lizard) clade includes thecodontians, saurischians, ornithschians, crocodilians, and the flying pterosaurs (Weishampel et. al, 2007). The only members of the archosauria clade still alive today are crocodiles and alligators (Parker, 2000). A few of the dinosaurs were enormous in size, but most were around the size of bulls, and a few were as small as chickens.
Dinosaurs are commonly believed to have evolved from a small, crocodile-like animal; however, a review of the known fossils provides no evidence for dinosaur evolution from non-dinosaurs, despite the excellent and abundant dinosaur fossil record. Dinosaurs appear abruptly in the fossil record and disappear just as suddenly.
In spite of years of intensive effort, major disagreement still exists among the experts on dinosaur classification, which is one reason why determining their phylogeny is so difficult for paleontologists. The most recent taxonomy proposal is not based on evolution or fossil trees but cladistic analysis using 107 anatomical traits (Weishampel et. al, 2007). The fact is, how “closely related one fossil animal is to another is very much a matter of opinion” (Horner and Lessem, 1993 , p.128), and this is one reason why so much disagreement exists about their phylogeny.
The Origin of Dinosaurs
One of the most common phylogeny theories today is that dinosaurs evolved from the thecodont, an alligator-like reptile, that first appeared in the fossil record during the Triassic (Benton, 1984). Thecodonts, a term meaning “socket-toothed,” were large, heavy crocodile-like animals that crawled low to the ground and on all four legs. They had long jaws and tails similar to crocodiles, and for this reason some argue that they were only a type of primitive crocodile. The theory is that a thecodont’s (or some other Archosaur’s) limb position evolved to allow the dinosaur precursors to walk in a more upright position until they eventually could walk on their back legs, becoming the dinosaurs that we know today. from the fossil record. This speculation is not directly based on evidence but is the most plausible conjecture postulated for dinosaur evolution because all other possibilities are even less tenable. No fossil evidence exists for this widely accepted theory, or for any of the other less accepted theories.
Another candidate for the earliest direct dinosaur ancestor is a housecat-sized animal named Lagosuchus, believed by evolutionists to have lived 235 million years ago in Argentina (Horner and Lessem, 1993). Some paleontologists speculate that “Lagosuchus or one of its relatives may have been the ancestor of the dinosaurs” because they possessed “many of the features thought to be present in [the] oldest dinosaurs” (Forster, 2000, p. 44). From the fragmentary remains recovered so far, Forster (2000) concludes that Lagosuchus is “probably not the ancestor” of dinosaurs but “is at least closely related to the ancestors of the dinosaurs” (p. 45).
Others argue that yet some other Archosaur that appeared in the late Permian, many of which strongly resemble crocodiles, were their ancestor (Richardson, 2003, pp. 40–41).
These many theories are all unconstrained by fossil evidence but rather rely on morphological comparisons and conjecture. Consequently, the imaginations of Darwinists are allowed great freedom in developing hypotheses.
Some evolutionists reject all of these theories, concluding that dinosaurs evolved from some “unspecified quadrupeds” (Weishampel, 1990 p. 193).
Constructing phylogenic trees has proved so difficult that parallel evolution has been proposed to explain the existing conflicting tree hypothesis (Romer, 1966, p. 136). Some argue for diphyletic (having two separate) origins, others for three or four or more separate origins from different stem archosaurs (Fastovsky and Weishampel, 2005).
The group class Thecodontia has now been abandoned by many paleontologists. Although the monophyletic view now dominates, evidence for “multiple roots of Dinosauria might still exist and in fact may be more obvious now that the cover of ‘Thecodontia’ has been blown” (Fastovsky and Weishampel, 2005, p. 91). The reason for these disagreements is because these theories are based largely on speculation, not fossil evidence (Fastovsky and Weishampel, 2005).
The Fossil Record
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| Herrerasaurus Artist's impression |
The fossil record indicates that dinosaurs were “extremely rare in the early part of the Late Triassic,” but by the end of the Triassic entirely “new groups of dinosaurs” had rapidly “spread world wide in an ever-increasing array of species” without leaving a trace of fossil evidence (Forster, 2000, p. 49). The fact is that no one knows why this “ever-increasing array” of new species occurred, nor do we have any fossil evidence to document their evolution— “abrupt appearance” is the only term that can describe what the fossil record reveals.
The process used to find a clade’s ancestor is to use the hierarchy of characters in the cladogram to determine what features should exist in an ancestor. The next step is to find evidence of "an organism that most closely matches the expected combinations of characters and character states. As we have seen, the likelihood of the very progenitor of lineage being fossilized is nil; however, we can commonly find representatives of closely related lineages that embody most of the features of the hypothetical ancestor" (Fastovsky and Weishampel, 2005, p. 92).
Tyrannosaurus rex
The best-known dinosaur is T. rex, an 18-foot-tall, 42-foot-long 14,000-pound monster, the largest carnivore that has ever lived. So far 32 T. rex specimens have been located, half of which are close to complete (Weishampel et al., 2007).
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| EoraptorArtist's impression |
Darwinists estimate that dinosaurs first evolved 225 million years ago, and T. rex 190 million years ago. How they know this from only 32 specimens is unknown. So far, not a single direct T. rex ancestor has been located. Potential ancestors, including Coelophysis, Herrerasaurus, Eoraptor, and Allosaurus, all have been eliminated by most experts as possible T. rex ancestors
The leading experts, Horner and Lessem, admit the animal that the T. rex and the tyrannosaurids evolved from is not known: “maybe they came from the allosaur line of big predators, maybe they came from a common ancestor, along with the Troodontids, a man-sized group of dinosaurs with many birdlike features” (Horner and Lessem, 1993, p. 127). They conclude a logical T. rex dinosaur ancestor is a meat-eating creature, but “which one we can’t say yet”.
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| Life restoration of Allosaurus fragilis |
Clearly, the “evidence is limited and there continue to be many disagreements” in the field of dinosaur phylogeny, and often these disagreements are to the degree that it calls into question the basis of dinosaur macroevolution (Parker, 2003, p. 159).
Another problem is that dinosaurs were not primitive as the word is normally defined. An example is the intelligent design of the eye of T. rex. It has been assumed that they had very poor, fussy vision, but recent research has shown that they were able to achieve very detailed images similar to that of many modern animals (DeYoung, 2000). Many other examples exist to show that dinosaurs were very well designed for their environment.
Conclusions
Over 30 million dinosaur bones and parts, some in excellent states of preservation, have been identified, and although much speculation exists, not a single documented plausible direct ancestor has yet been located. All known dinosaurs appear fully formed in the fossil record. As Forster (2000, p. 42) admits, “much mystery remains about the origin of the dinosaurs.” Several possible candidates for their ancestors have been suggested, but difficulties exist with all of them, and most are likely only extinct reptiles and not evolutionary links.
The more paleontological discoveries that are made, the more we realize our knowledge is complete and still no ancestral form is found. As a result, paleontologists are forced to conjecture about their ancestors based on little evidence. In conclusion, no credible evidence exists for dinosaur evolution from a primitive precursor animal, supporting the creation model. Dinosaurs appear suddenly and evidently also went extinct rather suddenly.
References (selected)
Benton, M. 1984. The Dinosaur Encyclopedia. Aladdin, New York, NY.Croft, L.R. 1982. The Last Dinosaurs: A New Look at the Extinction of the Dinosaurs. Haslam Printers Ltd, Chorley, Lancashire, UK.
DeYoung, D. 2000. Dinosaurs and Creation. Baker Books, Grand Rapids, MI.
Fastovsky, D.E., and D.B. Weishampel. 2005. The Evolution and Extinction of the Dinosaurs, 2nd edition. Cambridge University Press, New York, NY.
Forster, C. 2000. The first dinosaurs. In Silverberg, R. (editor), The Ultimate Dinosaur, pp. 41–52. Ibooks (A Division of Simon and Schuster), New York, NY.
Horner, J., and D. Lessem. 1993. The Complete T. Rex. Simon and Schuster, New York, NY.
Parker, S. 2003. Dinosaurs: The Complete Guide to Dinosaurs. Firefly Books, Crescent Richmond Hill, Ontario, Canada.
Richardson, H.. 2003. Dinosaurs and Prehistoric Life. Dorling Kindersley, New York, NY.
Romer, A. 1966. Vertebrate Paleontology. University of Chicago Press, Chicago, IL.
Weishampel, D. (editor). 1990. The Dinosauria. University of California Press, Berkeley, CA.
Weishample, D., P. Dodson, and H. Osmolska (editors). 2007. The Dinosauria. University of California Press, Berkeley, CA.
Cool pictures
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