Scott Faust Molecular Evidence Here we go again folks with M. Denton's silly +quot;typolog

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Scott Faust Molecular Evidence Here we go again folks with M. Denton's silly "typology" argument... ANADI DASA to ALL, 06-09-93, re: "Does Evidence Support Des" > In recent years, geneticists have discovered that in species of > similar form the DNA and other proteins have similar molecular > structures. More like recent decades. This was apparent as much as thirty years ago or more. Also, many proteins show clearly identifiable homology in the most widely diverse forms (like, say, bacteria, fish and humans), not just in "species of similar form". > So just as evolutionists have deduced ancestral relationships > among species from similarities in physical form, some of them now > deduce such relationships from the genetic similarities. And the topography of the phylogenies or cladograms produced from these two independent lines of evidence show very good general agreement. But then this is just a coincidence, right? > It is not, however, very surprising that similar species would > have similar genetic materials. But the main point is that such > similarities show nothing definite about how the organisms > orginated and cannot be used as proof of Darwinian-style > evolution. If an intelligent designer had produced varieties of > organisms with certain structural similarities, we would also > expect to see parallel molecular relationships. Maybe, but this is -not- the pattern that we find when all the evidence is considered. Because rates of morphological change can vary greatly among different lineages, and because many standard taxa are therefore "paraphyletic" or even "polyphyletic" rather than monophyletic, there are cases where the typology of evolutionary relationships does not correspond well to the overall "structural similarities" upon which conventional classifications are based. And even when taxa are monophyletic, taxa of equal rank do not always (or even, I would guess, usually) correspond to equivalent hierarchical levels in terms of branching evolutionary relationships. In such cases similarities at the molecular level stubbornly correspond to phylogenetic relationships (specifically, the relative amount of time since two forms last shared a common ancestor) rather than to overall structural similarities. For example, we have long known on the basis of comparative anatomy and the fossil record that crocodiles are more closely related to birds than they are to any of the other living reptiles. Crocodilians are the last surviving archosaurs or "ruling reptiles". Dinosaurs were also archosaurs. All archosaurs, including the crocodiles, evolved from a group of reptiles called thecodonts. As to birds, we know that they either evolved directly from dinosaurs (currently the stronger theory), or that they evolved more directly from the thecodonts. In either case they would share a common ancestor with crocodiles among the thecodonts. But if we want to find ancestors shared by crocodiles and non-ruling reptiles (turtles, snakes, lizards) we would have to go further back in time, probably back to the stem reptiles. Now, if the evolutionary scheme I have described is correct, and crocodiles and birds did share a more recent common ancestor than crocodiles and non-ruling reptiles, then we should expect them to be more similar at the molecular level, not withstanding that crocodiles happened to have remained essentially reptilian whereas birds have been extensively modified. If your non-evolutionary scheme is correct then crocodiles should resemble other reptiles at the molecular level more than they do birds. You want to take a guess as to which is the case? Another example along this same line involves humans and apes. At the molecular level is not possible to separate humans and apes at all, for chimpanzees and gorillas resemble humans much more closely at the molecular level than they do orangutans. (Indeed, it even appears at this point that humans and chimps are more similar than chimps and gorillas, but the differences in this case are extremely slight and difficult to resolve conclusively.) This result jives well with the fossil evidence since the discovery that _Siva/Ramapithecus_ was an orangutan like form and not an early hominid (human ancestor) as was once thought. If Ramapithecus still stood as a hominid it would place the human / african ape split too early to fit with the molecular data. ~~~~~~~~~~~~~~~ NOTE TO ALL: Although I have been told that it is correct, I'm not entirely happy with my reference to the fact that crocodiles and birds are more similar at the molecular level than crocodiles and lepidosaurs. This was first brought to my attention by the Texas antievolutionists and textbook activists Mel and Norma Gabler. With characteristic denseness and ironic ineducability, the Gablers persist in claiming that this is evidence -against- evolution! They also give a similar example based on the fact that horseshoe crabs are "more similar to spiders". Ironically (in light of their frequent complaints about poor grammar in textbooks) they don't say "more similar" to WHAT; but I assume they mean crustacean type crabs. This, of course, is a case just like the other. Scientists recognized that _Limulus_ is more closely related to arachnoids than to crustaceans long before the molecular evidence was even available, and in this case I believe that even conventional (non-cladistic) classifications reflect that. Anyway, if anyone (possibly Jeff Otto) can give me some solid references concerning the molecular similarities of crocodiles/lepidosaurs/birds (and maybe the horseshoe crabs/arachnoids/crustaceans as well, though I don't think its as useful an example) I would appreciate it. I think that I will also post this in Other examples that could be used in this argument, of cases where overall "typological" similarity differs from phylogenetic relationships, would also be appreciated. This line of argument occurred to me when I first read the Gablers bit about crocodiles and birds. I think it is a useful supplement to the more straightforward refutations of Denton's arguments about molecular homologies, but I've never seen anyone else use it in the various responses to Denton that I have consulted. As I am a scientific lay person, I would thus be interested in comments from those more knowledgeable. Thanks! ~~~~~~~~~~~~~~~ > In one of his recent books, prominent astrophysicist Sir Fred > Hoyle reproduced a chart purporting to show evolutionary > relationships among species based upon molecular studies. He > observed, "One should not be deceived, however, by the elegance of > this result into thinking that [the chart] proves the existence of > an evolutionary tree. What it shows is that if a tree existed, > then it was like this." Whatever... But even Hoyle (who has some -very- strange views about evolution) would appear to recognize -- re his comment about the "elegance" of the result -- that evolutionary common descent -does- explain the evidence in a detail and specific manner. I would invite you to compare this to the arm waving nature of the explanation (or, rather, rationalization) that you have offered here. And in spite of its vague and general nature, it can still only explain selective portions of the data, whereas evolution successfully engages -all- of the data. > -Anadi Your name (which I am guessing is Indian?) leads me to ask you the following questions. I hope that I do not offend... Sometime ago, in an echo on a different net, I was asked about antievolutionism in other countries and cultures; and in religions other than christianity, judaism or islam. I admitted that I didn't know much, but since hinduism was specifically mentioned I said I knew that hare-krishna, at least, held an antievolutionary position, although I didn't know about mainstream hinduism. I'm curious if you might be hindu (or even hare-krishna)? I would also be interested to know if the book you mentioned awhile back, which supposedly documents that anatomically modern humans existed millions of years ago, might be written by a hindu or other non-christian type. You see I collect antievolution literature and would like to expand both my collection and knowledge of the subject beyond the christian and biblical type that predominates in north america. Thanks! --- FMail 0.92 * Origin: The OPEN FORUM S.D. CA (619)284-2924 v32bis (1:202/212)


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