The Giraffe: A Model of Intelligent Design
|May 30, 2011||Posted by vjtorley under Intelligent Design|
Image courtesy of Hans Hillewaert and Wikipedia.
The recurrent laryngeal nerve of the giraffe is one of Professor Jerry Coyne’s favorite pieces of evidence for evolution. It is also the topic of a recent post of his on Why Evolution is True. Professor Coyne is certainly right about one thing: the recurrent laryngeal nerve of the giraffe is relevant to the debate on Intelligent Design. However, Professor Coyne’s argument (which has also been recently made by Professor Richard Dawkins) that the recurrent laryngeal nerve of the giraffe is poorly designed has already been dissected and thoroughly refuted by Casey Luskin here, here, here, and here, and by the geneticist Wolf-Ekkehard Lonnig in his online article, The Laryngeal Nerve of the Giraffe: Does it Prove Evolution? so I will not comment any further on it here.
In today’s post, I’m going to briefly outline the evidence for intelligent design in the giraffe.
People who enjoy looking at giraffes in the zoo often fail to reflect what an exquisitely adapted animal the giraffe is. Since giraffes have long legs, they also need long necks for drinking water, as they have to bend their heads to the ground whenever they drink. That might look easy enough to do, but it requires a suite of adaptational features in the giraffe’s anatomy, to keep the blood vessels in the giraffe’s brain from bursting. As Professor William Dembski and Dr. Jonathan Wells explain in their highly readable Intelligent Design text, The Design of Life (Foundation for Thought and Ethics, Dallas, 2007):
When a giraffe stands in its normal upright posture, the blood pressure in the neck arteries will be highest at the base of the neck and lowest in the head. The blood pressure generated by the heart must be extremely high to pump the blood to the head. This, in turn, requires a very strong heart. But when the giraffe bends its head to the ground it encounters a potentially dangerous situation. By lowering its head between its front legs, it puts a great strain on the blood vessels of the neck and head. The blood pressure together with the weight of the blood in the neck could produce so much pressure in the head that without safeguards the blood vessels would burst.
Such safeguards, however, are in place. The giraffe’s adaptational package includes a coordinated system of blood pressure control… Pressure sensors along the neck’s arteries monitor the blood pressure and can signal activation of other mechanisms to counter any increase in pressure as the giraffe drinks or grazes. Contraction of the artery walls, the ability to shunt arterial blood flow bypassing the brain, and a web of small blood vessels between the arteries and the brain (the rete mirabile, or “marvelous net”) all control the blood pressure in the giraffe’s head. The giraffe’s adaptations do not occur in isolation but presuppose other adaptations that must all be coordinated into a single, highly specialized organism. (p. 41)
In a figure on the same page, Professor Dembski and Dr. Wells also point out that increased muscle fiber in the giraffe’s artery walls toward the head allows greater control through artery constriction. Additionally, a complex system of heavily valved veins controls the return of blood to the heart.
Clearly, the giraffe is a wondrously adapted creature. Not one but several simultaneous fine-tuned adaptations seem to have been required, in order for a giraffe to evolve from a short-legged, short-necked creature. The difficulty for neo-Darwinists should be obvious. How could such an adaptational suite of features evolve as a result of a natural process that lacks foresight, especially when the components of the package are at best useless and at worst detrimental, until the whole package is in place?
The giraffe, far from being an embarrassment to Intelligent Design proponents, is one of our star exhibits in the animal kingdom. To knock it off its pedestal, neo-Darwinian evolutionists would have to adduce genetic or fossil evidence showing that the various components of the giraffe’s adaptational package of features actually appeared at different times in the past, and could therefore have evolved independently of each other. But as geneticist Wolf-Ekkehard Lonnig demonstrates in a 2010 paper entitled, “The Evolution of the Long-Necked Giraffe: What do we really know?” (see here for Part I and here for Part II), the long-necked giraffe appears suddenly in the fossil record: no intermediate forms have been found. Lonnig writes:
A conclusive mechanism for the appearance of the long-necked giraffe is thus far completely unknown.
His conclusion is well worth quoting:
Whoever, after a detailed study of the peculiarities of the giraffe, does not understand that it really is an animal species that is “altogether exceptional, novel, and specialized” is someone to whom Lord Acton’s words may apply: “The worst use of theory is to make men insensible to fact.”
Lonnig lists no less than four pages of research proposals inspired by Intelligent Design, relating to giraffes and okapis (both of which belong to the same family). So much for the common canard that Intelligent Design is anti-science!
I have seen many academic rebuttals in my lifetime, but Lonnig’s systematic demolition of the standard evolutionary narrative of how and why the giraffe evolved its long neck is simply devastating. No wonder the proponents of neo-Darwinian evolution don’t want to talk about his work.