The giraffe is an integrated adaptational package whose parts are carefully coordinated with one another. To fit successfully into its environmental niche, the giraffe presumably needed long legs. But in possessing long legs, it also needed a long neck. And to use its long neck, further adaptations were necessary. 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 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 all must be carefully coordinated into a single, highly specialized organism.
In short, the giraffe represents not a mere collection of isolated traits but a package of interrelated traits. It exhibits a top-down design that integrates all its parts into a single functional system. More.
In any field other than Darwinism (= current evolutionary biology), the correct term for all that is engineering. We do it all the time with computers. But the Darwinians are permanently stuck at the level of just-so stories (= How the giraffe got its long neck” – See Claim-of-the-day files for current trivial explanation)
It would be fun to hear Darwinians explain the evolution of the tablet with no reference to design or purpose. Oh wait, they did that with the electric car, and thought they were being very clever indeed.
Note: For a limited time, you can buy The Design of Life for $10.
See also: The Giraffe: A model of intelligent design (Vincent Torley)
W.E. Loennig’s “The Evolution of the Long-Necked Giraffe,” Part II Granville Sewell
Evolution of the Long-Necked Giraffe (William Dembski)
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