(Blame Shakespeare for the delay)
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The mammalian Recurrent Laryngeal Nerve (branching of the Vagus Nerve) is a wonderful example in favour of unintelligent design. Any engineer will notice the unnecessary inefficiency caused by the awfully pointless route it takes. Why? It's purpose is to deliver "motor function and sensation to the larynx (voice box)" to basically connect your brain with the larynx. Due to this relatively simple task and the close proximity, you would rightly assume that the nerve would take the shortest and most direct route. Like by the few centimeters it takes to get from the brain to the voice box. That would be great design! Praise Jebus!
Back to seriousness. So what actually happens with the nerve? Well, instead of taking the optimal (and intuitive) route, it skips past the larynx, loops underneath the heart, traverses back up the neck and then finally reaches its destination it previously skipped. It doesn't take a genius to realise this is utterly unnecessary and downright terrible design. For humans (and most other mammals), this means our wiring is seven times the length that it needs to be! As the above image demonstrates, Giraffes unfortunately get the worst end of the stick, with their laryngeal surpassing 13 meters in length (also resulting in the giraffe being almost mute), as opposed to the simplest pathway of a few inches. This is pretty much the epitome of inefficiency and inadequacy.
A perfect fit for evolution
A common creationist response is "if it's so inefficient, then why is it okay for evolution?!". This isn't a refutation nor is it even a chink for evolutionary theory. It's just a proclamation of ignorance.
Evolution can only work with what it has. There's no restart or reverse button when it comes to inheritance and natural selection, only a modification of existing features. Because of this, evolution couldn't start afresh when our fishy ancestors began to evolve a more mammalian-like morphology. It was forced to utilize the already present engineering and had to lengthen the wiring instead of backtracking and reversing the entire process. The reason why our ancestors had such wiring in the first place is simple: for fish, it's the quickest route. They lack the mammalian neck and so the most direct and reasonable pathway was to "innervate one gill slit, and pass near the gill arch. Since then gills have evolved and the gill arch has became a dorsal aorta." (Thank you, Wikipedia)
Since a picture is worth a thousand words, here's three thousand encapsulating the transition:
So it's easy to see how this fulfills the prediction regarding the messy and imperfect design of evolution. We expect such jagged arrangements, it's an inexact art. For the Creationists, however, it's a bit more difficult - but it's nothing some deliberate ignorance on the subject won't fix. Or, of course there's always the typical "we don't know everything about it yet!". That's probably true, but it's certainly eluded science for quite some time, and is a pretty lame argument. It's an appeal to ignorance, and doesn't hold up well against scientific scrutiny. Another response I've come across is simply that "it works fine for what it was designed for." Well, it works, I'll give them that, but not exactly well. Wouldn't an intelligent designer opt for the most efficient and streamlined solution? What's with the excessive wastage and the blatant over-complication?
A more "scientific" (sounding) response to the problem by Creationists is this, but it was soon demolished by this, not unlike any other Creationist article.
Synopsis:
The Recurrent Laryngeal Nerve follows quite an anti-intuitive route, involving a huge detour around the dorsal aorta instead of taking the obvious and most direct pathway of a few inches from the brain to the voicebox. This results in the laryngeal being up to seven times longer than necessary, and up to 15 meters longer in giraffes, rendering them near mute. This route is explained by the evolution of mammals from fishes as proven by the fossil record. Although the example is not definitive proof for evolution, it complies perfectly with our expectations and thus is a fantastic indicator of the rugged and unintelligent processes of evolution.
