Wednesday, October 13, 2010

The Recurrent Laryngeal Nerve Must Have a Rational Design

Casey Luskin is at it again. The Intelligent Design Creationists are trying to argue their way out of the obvious implications of the path taken by the recurrent laryngeal nerve, especially in giraffes.

Now they're saying that, far from being an example of sloppy design, the path of the nerve has to have some selective advantage according to science. Thing is, you need to have a proper understanding of evolution in order to discuss this intelligently.

Enjoy, while keeping in mind why we call them IDiots [Wolf-Ekkehard Lönnig: Under Neo-Darwinism, the Recurrent Laryngeal Nerve Must Have a Rational Design.


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  2. If I understand right they are saying that, IF the recurrence is inferior, AND there are some people and presumably animals without the recurrence, THEN the non-recurring form SHOULD HAVE become dominant.
    But the non-recurrent forms are pathological no, at least that's what I got from the description, they're associated with a pathology.
    So just because there is a non-recurrent configuration, doesn't mean that its going to improve fitness.
    Or am I missing some subtlety as to why the non-recurrent form, despite the pathology that generates it, must be superior?

    Also, isn't this silly, don't IDiots, are the really arguing that yes, the best design is the recurrent one??? I mean, the reccurrence is because of restraint, if there was a designer, there wouldn't be that restraint (coupling with the aorta, which is a stupid design).

  3. It is yet another silly adaptationist strawman, but they can't even get that right. They don't show no evidence for the non-recurrent having some inheritability and then they don't show a clear causal link between the non-reccurent form and pathology.

    Lönning: "The embryological nature of such a nervous anatomical variation results originally from a vascular disorder, named arteria lusoria in which the fourth right aortic arch is abnormally absorbed, being therefore unable to drag the right recurrent laryngeal nerve down when the heart descends and the neck elongates during embryonic development." Defechereux et al. 2000

    Although this variation generally seems to be without severe health problems, it can have catastrophic consequences for the persons so affected: problems in deglutition (difficulties in swallowing) and respiratory difficulties (troubles in breathing) (see Rammerstorfer 2004; moreover "dysphagia (if the pharyngeal and oesophageal branches of nonrecurrent or recurrent inferior laryngeal nerve are injured)" - Yang et al, 2009)

    Did he pondered if the arteria lusoria condition has something to do with the "catastrophic consecuences"? It does. Also, what's the point on noting that damage in either recurrent or non-recurrent nerves causes dysphagia?

  4. the ungrateful bastards full of hubris...