Study Says Spider Web Developed Just Once

Study Says Spider Web Developed Just Once, ABC News, Randolph E. Schmid AP ... [Graphic: BBC] Washington Jun 22, 2006 (AP) - Will you walk into my parlor, said a Cretaceous spider to an ancient fly. The classic spider's web, like Charlotte would have woven, was invented just once, way back in the Cretaceous period some 136 million years ago, scientists report. Called an orb web, it's the generally circular style spun by two major types of spiders, which had raised the possibility of the two groups evolving this form separately. But a paper in Friday's issue of the journal Science says a comparison of the spider genes related to web making shows that the orb web developed just once. Researchers led by Jessica Garb of the University of California, Riverside, compared orb-web building spiders in the genuses Deinopoidea and Araneoidea. Both build orb webs to catch prey and the deinopoids also include net-casting spiders that throw a modified orb web over their prey. Araneoids include the orb weavers such as golden silk spiders with their traditional spiraling web as well as those that weave sheet webs. Garb said in a statement that the finding "does not support a double origin for the orb web," but indicates that the unique design evolved only once. While the two groups probably developed orb-web spinning from a common ancestor, they came up with different ways of making the web catch prey. Araneoid webs have glue droplets that make prey stick to the web, while deinopoids wrap their threads with a different type of silk fiber that "the spiders comb, until it almost has the appearance of Velcro under a microscope, and they snag insects that way," Garb reported. Not all spiders make orb webs. The black widow, for example, weaves a web that is a tangle of silk without the circular pattern. ... [I accept the Darwinist reasoning that if something arose many times independently, then that is evidence for it being the result of the Darwinian mechanism of the natural selection of random micromutations (I do not rule out such Darwinian mechanisms-after all Darwin just discovered them, he did not invent them).

For example, when Darwinists used to claim that "eyes have evolved independently more than forty times in the animal kingdom":

"All that is needed as the starting point for the development of eyes is the existence of light-sensitive cells. Natural selection will then favor the acquisition of any needed auxiliary mechanism. This is why photo-receptors or eyes have evolved independently more than forty times in the animal kingdom (Plawen and Mayr, 1977)." (Mayr, E.W., "The Growth of Biological Thought: Diversity, Evolution, and Inheritance," Belknap Press: Cambridge MA, 1982, p.611)

then they could, with justification, claim that it was by natural selection from "light-sensitive cells."

But equally, when it was discovered that there was a pax-6 master gene that coded for all "forty and maybe up to sixty-five" different types of eyes, and therefore "there has been just one origin and one evolutionary [sic] line of progression" of eyes":

"The Pax-6 story tells us that there has been just one origin and one evolutionary line of progression, from the earliest patches of light-sensitive cells to the variety of advanced eye-forms around us. This unavoidable conclusion, Charles, goes against a hundred years of insistence that the widely different structures and operations of eyes (eye cup, pinhole, camera-type with single lens, mirror and compound) arose independently, at least forty and maybe up to sixty-five times. Our old friend Richard Dawkins devoted a chapter in one of his books to 'the forty-fold path to enlightenment', emphasizing the repetitive ease with which natural selection could produce an eye, and so relieving you of the 'cold shudder' you experienced whenever you grappled with this problem." (Dover G.A., "Dear Mr Darwin: Letters on the Evolution of Life and Human Nature," [1999], University of California Press: Berkeley CA, 2000, reprint, p.172)

then that is good evidence against "the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration" having "been formed by natural selection":

"To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree. When it was first said that the sun stood still and the world turned round, the common sense of mankind declared the doctrine false; but the old saying of Vox populi, vox Dei, as every philosopher knows, cannot be trusted in science. Reason tells me, that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, as is certainly the case; if further, the eye ever varies and the variations be inherited, as is likewise certainly the case; and if such variations should be useful to any animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, should not be considered as subversive of the theory." (Darwin, C.R., "The Origin of Species By Means of Natural Selection," 1872, Sixth Edition, Senate: London, 1994, pp.143-144)

Similarly, if there has been one just one origin and one line of progression of anything (especially if it seems to be irreducibly complex), then I provisionally propose that it has not arisen by unintelligent `blind watchmaker' processes but by intelligent design (and as a Christian I assume, but cannot prove, that the Designer was God).

A case in point is this orb spider web that seems to be a "unique design" which "evolved [sic] only once." Since it presumably would be very advantageous for other lines of spiders to develop this type of web, that they didn't (given the uncountable trillions of spiders that have ever lived) is evidence that this "unique design" arose fully-formed by an inheritable macromutation (which would be indistinguishable from a miracle-which I assume it was, i.e. what Geisler calls a "second-class miracle"):

"It may be that some things are so highly unusual and coincidental that, when viewed in connection with the moral or theological context in which they occurred, the label `miracle' is the most appropriate one for the happening. Let us call this kind of supernaturally guided event a second class miracle, that is, one whose natural process can be described scientifically (and perhaps even reduplicated by humanly controlled natural means) but whose end product in the total picture is best explained by invoking the supernatural. Providing that the theist can offer some good reasons (by virtue of the moral or theological context of the event) for not accepting a purely natural explanation, then there is no reason to rule out the evidential value of such unusual natural events." (Geisler, N.L., "Christian Apologetics," [1976], Baker: Grand Rapids MI, Ninth Printing, 1995, p.277)

This is supported by the fact that the web-building instinctual program of orb web spiders is to build a whole web from scratch. That is, if its web gets damaged the spider cannot repair it but "the spider has to make a new web from scratch, instead of recycling the old web" (despite the enormous selective advantage if they could repair their web by rebuilding only part of it, which is evidence that they never could build part orb webs).

And here is some idea of the complexity of an orb web (and therefore of the instinctual program `hard-wired' into the tiny brain of each orb-web spider):

Spiders Spin Out, ABC, February 5, 2004 ... To build a wheel web from scratch, the spider begins on top of a bush or tree and spins out a length of silk. She waits for a breeze to lift the gossamer thread and eventually snag it in a nearby tree. Having assured herself it is secure, she climbs along this thread, spinning a stronger line as she goes. Then she returns, paying out a much looser line behind her which sags down. She attaches another line to the middle of the slack line, and runs this line down to the ground. With the end attached below, the whole makes a Y-shape - three 'spokes' which form the hub or centre of the web. Then she adds more spokes - up to 60 depending on the species. Now she lays down a continuous spiral to join up the spokes, working from the centre outwards. All the web spun so far has been dry silk, but now the spider, working from the outside back in towards the hub spins the most important feature: a spiral of sticky insect-ensnaring silk. Her work done, she takes up residence in the centre or in a curled leaf. ...]

Stephen E. Jones, BSc (Biol).
`Evolution Quotes Book