...the existence of even one intelligently designed feature in living things (at least prior to human beings) would overturn the Darwinian theory of evolution that currently dominates Western biology.
This is of course false. There is nothing within evolutionary science that precludes the existence of even one intelligently designed feature in living things, or even thousands for that matter.
It's a shame, however, that with the bar set so exceedingly and ridiculously low ("even one") the ID preachers can't come up with even that..
"...the existence of even one intelligently designed feature in living things (at least prior to human beings) would overturn the Darwinian theory of evolution that currently dominates Western biology."
Ah. I see. One example of a biological feature unexplainable by modern Darwinian theories is no basis for rejection of present theories, but one example of biological claim you believe to be fallacious is enough to discard the entire essay which contains it. Nope, no hypocrisy here.
Btw, even if that assertion is wrong, it is not set up as a logical fallacy. Things which are incorrect are not de facto logical fallacies. Using one unrelated argument to "disprove" something else, however, is. Just for your consideration...