Subject: gaps in the fossil record } the evidence from the fossil record to support evolut

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Subject: gaps in the fossil record } the evidence from the fossil record to support evolution is largely } missing and that critical gaps indicate a single creation of life } as it is today. }The fossil record is incomplete and there are no transitions evident Such a prediction by creationists is rare. The implication of this is that if gaps in the fossil record are ever filled, creationism is falsified. Those outside professional paleontology often find it difficult to access what the fossil record does and does not show. As someone who works within the field of human paleontology and human evolution, I often find it odd when I am told that the number of human fossils is much too meager to allow the sort of extrapolation claimed by biologists for human ancestry. This may have been true 20 years ago, but it certain is not the case now. This might lead one to wonder if the fossil record is not also underrated in the are of other organisms as well. An article in the book _Science and Creationism_, edited by Ashley Montague, addresses this point. The article is by noted paleontologist Roger J. Cuffey, one of the witnesses called to testify in the now famous Arkansas creation science case in 1982. Allow me to quote form the article, entitled "Paleontological Evidence and Organic Evolution,": "If we read the paleontologic literature (especially if with the background of professional paleontologic training and experience) we find that the fossil record contains many examples of such transitional fossils. These connect both low-rank taxa (like different species) and high-rank taxa (like different classes), inspite of the records imperfections and in spite of the relatively small number of practicing paleontologists. Because of the critical role which transitional fossils played in convincing scientists of the occurrence of organic evolution, paleontologists have been appalled that many otherwise well- informed persons have repeated the grossly misinformed assertion that transitional fossils do not exist." Cuffey the goes on to list no fewer than 185 references in the paleontologic literature documenting such transitional forms. One of my favorites is the fossil Therapsid, Diarthognathus. In the fossil record, reptiles are distinguished from mammals by the number of bones that form the lower jaw. This is not a trival distinction, since the musculature of the reptilian jaw is different from that of mammals and would require such a re-design. Essential, reptiles have a lower jaw made of three bones (dentary, articular and quadrate) while mammals have only a single bone (the dentary), with the articular and quadrate relocated to the middle-ear (reptiles have only one ear ossicle, mammals have three. The relocation of this bones is observable embryologically in modern mammals). Therapsids are "mammal-like reptiles" and have a number of traits that put them midway between mammals and reptiles. The skull is larely reptilian but the dentary is much larger than in modern reptiles and other fossil reptil groups. Also, the therapsids have heterdont teeth (different shapes for different functions as in mammals) and limbs located underneath the body, rather than out to the side (not as far underneath as in mammals, however). Diarthrognathus is a therapsid with both a mammalian and reptilian jaw joint. Both are functional, but the mammal-like joint seems to have been the most functional. The quadrate and articular bones are very reduced. The animal is literally hafe-way between a mammal and a reptile. One more thing. I think it unfair to list Denton with other respected biologists. Denton is not a biologists and, while not religious either, had his own philosophical axe to grind against what he felt are the dehumanizing implications of evolution. A recent review of Denton's book appears in the July-August Issue of the NCSE Reports (published by the national center for science education ). The review, by biologists William M. Thwaites, points out the numerous errors, misintepretations and misrepresentations in Denton's book. Denton, as do many religious creationists, relies on outdated material often quoted out of context, and does not seem to understand the implications of the examples he uses, especially those using biochemical evidence. Thwaite concludes: "...Denton's book is just another typical anti-evolution tract. It shows that Dento is motivated, not by a desire to understand the workings of nature, but by apparent fear of "agnostic," "materialistic," and "skeptical outlook of the twentieth centure." }The fossil record is incomplete and there are no transitions evident The fossil record will never be complete, but it is certainly more complete than it was in Darwin's day. Darwin`s prediction that the "holes" would be filled has come true. Transitional fossils now exist for all vertebrate groups. Transitional forms also exist for most major invertebrate groups and for most groups of plants. For those of you without the fortitude to wade through the paleontological literature, a wonder source of information is an article by Roger J. Cuffey in the book _Science and Creationism_ (edited by Ashley Montague). This book should be fairly easy to obtain. In the article, entitled "Paleontologic Evidence and Organic Evolution" Cuffey lists no less than 220 references from various scientific journals documenting these transitional fossils. These transitions include connections between low rank taxa (like species) as well as high-rank taxa (like classes). It is interesting that much is made of the "evolution should not be treated as a fact" when the same people often talk about a lack of transitional forms between various taxa. Taxonomic groups are not facts. Taxonomy is an order imposed on the living world by scientists to make the diversity of life easier to deal with. Nonetheless, creationists and fellow travellers refer to it like it is written in in stone. From stassen@netcom.UUCP (Chris Stassen): For those interested in evaluating "intermediate forms", I'd recommend Chris McGowan's _In The Beginning_ (Prometheus). It's a "good place to start" for the layman (but by no means sufficient all by itself). He devotes two chapters (pp. 110-141) on detailed study of Archaeopteryx and the Cynodonts, comparing their features to those of the two groups which they fall between. While Archaeopteryx appears too late to itself be the transitional form between reptiles and birds, it does fall between the two categories. The Creationists contend that it is a bird - but a detailed study of features shows that it has less in common with birds (feathers, wishbone) than it does with Theropod dinosaurs (pubic peduncle, bony tail, no pygostyle, no bony sternum, three well-developed fingers, three well-developed metacarpal bones, metacarpal bones unfused, metatarsal bones separate, no hypotarsus, abdominal ribs). The first specimen found was accidentally classified as a reptile because the feather impressions were too faint to discern (until the fossil was specifically examined for them). I'll deal with Cynodonts more briefly, but when evaluated in 14 main areas where reptiles and mammals differ skeletally, they are clearly intermediates. They share five of the features with reptiles, five with mammals, and are somewhere in between on the other four. Since they appear in the fossil record at the proper time, and are connected by many other "transitional" fossils in a very detailed sequence, they represent one of the most well-documented transitional forms. (It should be no surprise that more recent transitions are better documented. More fossils are available, and more complex creatures probably change more slowly.)


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