Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site uwmacc.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!uwvax!uwmacc!dubois From: dubois@uwmacc.UUCP (Paul DuBois) Newsgroups: net.origins Subject: Jai Alai Message-ID: <1091@uwmacc.UUCP> Date: Thu, 16-May-85 17:21:27 EDT Article-I.D.: uwmacc.1091 Posted: Thu May 16 17:21:27 1985 Date-Received: Sun, 19-May-85 04:24:39 EDT Distribution: net Organization: UW-Madison Primate Center Lines: 140 Some statements have been made in this newsgroup recently that seem to me somewhat reckless. Ron Kukuk posted the following: >> 10. All species appear perfectly developed, not half >> developed. They show design [a]. There are no examples of >> half-developed feathers, eyes [b], Which prompted these two replies: > [Jeff Sonntag] > No half-developed eyes? Numerous single-cell animals have > half-developed eyes. Some multi-cellular animals have *very* simple eyes. > [Keith Doyle] > Depends on how you look at it. All species appear half developed, depending > on what you think they are developing toward. I think that neither of these statements is worthy of serious consideration until they are given some support. (For instance, Mr. Sonntag can give the phylogeny of vision. Mr. Doyle can show what half-developed visual structures turn into.) But perhaps before they try, I think that such statements can be rendered implausible by examples that illustrate the difficulties of such constructions. I present such an example below. The astronomers on the net ought to find this interesting. --- Lisa J Shawver, "Trilobite eyes: An impressive feat of early evolution". Science News, 105(5), 2 Feb 1974. "Although extinct for more than 300 million years, their fossil remains indicate that in one respect, the trilobites may have been superior to current living animals. They had, in principle, perfect vision: They possessed the most sophisticated eye lenses ever produced by nature." (The "in principle" is because the nervous system is what does the actual "seeing". It doesn't do much good to have a perfect eye if you are blind, for instance.) Shawver describes a discovery by Riccardo Levi Setti of the University of Chicago and the Fermi Institute, who realized that lenses of a certain class of trilobites were nearly identical to aspheric aplanatic lenses (lenses which minimize spherical aberration). Levi Setti arrived at the conviction that "trilobites had solved a very elegant physics problem and knew about Fermat's principle, Abbe's sine law, Snell's laws of refraction and the optics of birefringent crystal." (This is quoted from his book _Trilobites_.) Of course Levi Setti is speaking very loosely when he talks about trilobites "knowing", but we'll pass over that, since evolutionists allow each other to talk this way. The important point is that these are rather interesting structures. The article further quotes: "'Nature has developed a process of optimization, which in this case, produced these incredible sophisticated shapes,' says Levi Setti. 'It didn't happen by accident. It proves that evolution can produce this kind of thing ... the lenses look like they were designed by a physicist.'" One gets the impression that Levi Setti was impressed. Noteworthy is the statement that the eyes not happening by accident is proof of evolution. Design is evidence of no designer. I suspect that more reserved evolutionists would regard this as a rash statement. Levi Setti seems to have fallen into the curious mode of thinking in which the greater the sophistication of a structure, the stronger is the evidence that is shown for evolution. The more unlikely something is to have been produced, the "fact" that it did evolve shows how every powerful evolutionary processes are. If you can put yourself into the position of the creationist for a moment, you will begin to understand how ludicrous this seems to us. Well, anyway. It is not only the shape of the lenses that is remarkable, but also their structure. The remark by Levi Setti about solving a problem involving birefringent properties can be clarified by the following remarks. "The remarkable eyes of trilobites". Science News, 103(10), 10 Mar 1973, p154. "The eyes of trilobites, small, extinct arthropods of the Paleozoic era, have been found to possess sophisticated, glass-like lenses capable of producing relatively clear images over a wide depth of field. "The lenses owe their remarkable properties to their impregnation with the mineral calcite, specifically calcite with its crystal structure arranged so precisely as to produce the optical properties of glass." It should be noted that no known arthropod living today possesses similarly sophisticated visual structures. Kenneth M Towe, "Trilobite Eyes: Calcified lenses in vivo". Science, 179, 9 March 1973, 1007-1009. Towe studied two different trilobites: Phacops Rana - Devonian era Isotelus gigas - Ordivician era "As a highly birefringent mineral, calcite has a double refraction so pronounced that it is often used to illustrate the phenomenon. However, light passing in the direction of the _c_-axis (optic axis) is not doubly refracted and the mineral behaves isotropically with an index of refraction of 1.486. It is only in this special orientation that a lens made of calcite would be able to produce an image free of a doubling effect. Thus, the individual lenses of the schizochroal eye of _Phacops_ and the facets of _Isotelus_ are constructed of calcite so precisely oriented crystallographically that they behave as if they were made of glass. This unique crystallographic orientation, which is reproducible from specimen to specimen, cannot be considered an accidental postmortem or secondary replacement by calcium carbonate. Such a consistent and selective preferred orientation can only be due to a process of biomineralization. The calcite lenses must have been present during the life of the animals" [p1009]. --- Keeping these things in mind, thee are some questions that must be asked: In what sense are these eyes "half-developed"? What are (were) they developing toward/from? Remembering that these were fairly early organisms, what sort of phylogeny shall one construct to show the development of these structures? Yes, it is true that some organisms have *very* simple eyes. But some early organisms have very unsimple eyes. So statements about half-developed and simple eyes don't show much *unless* the line of descent is demonstrated. -- | Paul DuBois {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois --+-- | "Some trilobites had large eyes to enable them | to escape from their creditors more easily."