The Laryngeal Nerve of the Giraffe is Proof of Natural Selection

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This video, including comments by Richard Dawkins, documents a necropsy (an autopsy on an animal other than a human) carried out in a classroom on a giraffe. In this video, we follow the pathway of the recurrent (inferior) laryngeal nerve, an important nerve that is a branch of the Vagus nerve (tenth cranial nerve). The recurrent (inferior) laryngeal nerve, which branches off the Vagus nerve at the base of the brain, travels down the neck, around the arteries of the heart and travels back up the neck to ennervate the larynx, or voice box, thereby providing motor function. The purpose of doing this exercise is to show that there is no so-called "intelligent designer" because the pathway of this nerve is completely illogical -- unless, of course, you accept that evolution is the reason for this nerve's convoluted pathway through the body.

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Inside Nature's Giants. Awesome series.

Oh, I dunno, GrrlScientist. Maybe the IDiots think their god is Rube Goldberg.

This video reminds me of Steve Gould's wonderful essay on the Panda's 'thumb'. The IDiots and other creationists go on and on about the 'perfection' of nature, without ever realizing how much of that so-called perfection is really the co-option of biochemical pathways and structural features to do something new and different because that something happens to work a little better.

By Pete Moulton (not verified) on 22 Jun 2010 #permalink

Of course, your "there is no so-called "intelligent designer" because the pathway of this nerve is completely illogical -- unless, of course, you accept that evolution is the reason for this nerve's convoluted pathway through the body" ignores the infamous "it's not ours to reason why" and that old spiritual "G*d moves in mysterious ways." In other words, the fact you find it illogical only proves your limited capabilities of comprehension, not G*d's non-intelligence. :)

It was really one of the TV highlights of last year and thoroughly deserving of its BAFTA Award. I think the elephant was my favourite, but they were all good.
The second series is holding up well. I'm looking forward to tonight's show, with big cats. A much needed respite from the World Cup and Wimbledon.

How widely has it been shown on NatGeo?

I had surgery last year to repair my eardrum and the bones in my inner ear. The doctor warned me that the operation might impact my sense of taste and he explained that the nerve connecting my tongue to my brain takes a detour up and around and through my ear.

Intelligent design, my arse.

By Scott Hester-Johnson (not verified) on 23 Jun 2010 #permalink

"Intelligent Design" must have originated with some Wise Man being asked about 'Where do we come from?' Etc.

Not knowing anything about Geology etc. 'Intelligent Design' must have seemed to be logical to anyone believing in some form of Deity.

We now know that very early on in our development from a single cell we developed gills which turned into tonsils and we also had a tail. All of which traces our path from a swimming vertebrate to mammal to Human.

Alf Rider.
Forest Ontario.Canada.

By Alf Rider (not verified) on 24 Jun 2010 #permalink

These people need to learn the meaning of the word "proof". "Appears consistent with" would be a more appropriate phrase. They are an embarrassment to the pure sciences.

The well-known textbook Grayâs Anatomy states:

âAs the recurrent nerve hooks around the subclavian artery or aorta, it gives off several cardiac filaments to the deep part of the cardiac plexus. As it ascends in the neck it gives off branches, more numerous on the left than on the right side, to the mucous membrane and muscular coat of the esophagus; branches to the mucous membrane and muscular fibers of the trachea; and some pharyngeal filaments to the Constrictor pharyngis inferior.â6
Dawkins considers only its main destination, the larynx. In reality, the nerve also has a role in supplying parts of the heart, windpipe muscles and mucous membranes, and the esophagus, which could explain its route.

Even apart from this function, there are features that are the result of embryonic developmentânot because of evolution, but because the embryo develops from a single cell in a certain order. For example, the embryo needs a functioning simple heart early on; this later descends to its position in the chest, dragging the nerve bundle with it.

Also, would a circuitous route necessarily be bad design? There could be reasons for this (and in the case of the RLN we have a good idea, as per Grayâs). Biologist and geologist John Woodmorappeâs review of Jerry Coyneâs book Why Evolution is True (which Dawkins recommends for its section on the RLN (note, p. 356) points out:

âHuman-designed machines and structures are full of such things as circuitous wiring and plumbing, but that hardly means that they are not the products of intelligent design.

âNow let us consider situations in which a circuitous route is actually harmful to its bearer. The automobile with its engine in front requires a long, tortuous exhaust system perched underneath the car. This clearly makes it more vulnerable to injury from obstructions than the short exhaust system of engine-in-back cars (I speak from personal experience). Following Coyneâs logic, should we suppose that engine-in-front cars are not the products of intelligent design? No. We realize that there is an engineering trade-off between the advantages of the car with its front-situated engine and the concomitant disadvantage of its more easily-damaged long, circuitous exhaust system.â7
Also see the: Backwardly wired retina âan optimal structureâ: New eye discovery further demolishes Dawkins -

Although I believe in creation I can appreciate the arguments of evolutionists and do not dismiss accurate scientific findings. There must be a true explaination for these. Here are my comments if it helps. Just to note these are my own personal comments, not necessarily beloning to any religion.

1) It could be the lengthening of neck did take place over a long period as explained. This does not mean all aspects of evolution are correct. It may be that Giraffe did have shorter neck originally and elongated as a result of diversification. We know from observation that adaptation occurs in animals and plants. In contrast - in the biblical creation account there were many are different kinds created. The creation account does not exclude the possibility of change/diversifiction/adaption within their 'kinds'. The question left is what is meant by a kind. Evidently a 'kind' is much broader what people refer to as a species and the species within a kind are really just diversification. Fossil evidence I understand supports that many different kinds appeared at a similar time - which matches the bible account. If evolution was correct one would expect each not only each kind but each species to be separated by long periods of time and that there would be gradual changes in all cases. The fossil evidence I understand does not support this.

2) There could be other explainations for the nerve route that we do not yet understand. For example, if the nerve was short and direct could it be at risk being severed more easily due to neck movement. From physics, if an extension is applied to a small length of material it will be under greater stress. For a much longer length, the extensions is fractionally smaller and represents less stress. I am not suggesting this is a true explaination just that there may be things factors we dont understand not considered.

3) In design work, I have heard it said, a good design is a one that works well. It is a fact that some designs are not always as elegant as others but are still good. On the whole, the Giraffe is a marvellous design that works well - seems very good to me. Man often tries to copy design from creation because man's designs are not as good as the creator's. If the creator did leave any 'flaws' in the design perhaps it provides a means of testing the faith of believers.

4) Another sceintific explaination could be that there is a creator but that he can makes mistakes. I have to say I dont believe that myself - I rather believe the bible view that God is perfect. We do see in scripture that Joy is one of Gods qualities and we are encouraged to have this quality also. We see sense of humour sometimes in creation. Perhaps God designs in strange quirks just for fun.

In my view there are parts of evolution theory which are scientifically based and have a measure of truth, however large parts of it are based on a belief that there can not possibly be a God and are not backup by proveable science. To be truely scientific one needs to consider all possibilities including the possibility that there is indeed a creator. I started as an evolutionist but changed after a lot of examination of evidence. I imagine most evolutionists already have made their minds up and are stuck in their beliefs though. Most believers in God probably believe in God for other reasons not just a belief in creation. Most believers in God I imagine dont really want to know much about evolution - avoiding it like the plague as it could undermine their faith. There are also atheists who dont believe evolution and believers in God who also believe evolution.

Best wishes to all sides, no offence meant to any.