The Failures of Mathematical Anti-Evolutionism
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The Failures of Mathematical Anti-Evolutionism (Jason Rosenhouse) (z-lib.org)
(Rogers 2011, 57)
We should emphasize that the issue in both of these cases, and in the dozens more that could quickly be produced to illustrate the same idea, is not so much bad design as it is weird design. Engineers often have to make trade-offs and compromises when solving practi- cal problems. In such situations, something that initially appears to be poor design can instead be understood as the best possible solution given other constraints. That is not what we are talking about here, as the example of Figure 2.1 illustrates. The weird arrangement of roads did not arise because a civil engineer faced design constraints. Rather, the arrangement is such that no engineer would even have considered it. The roads are incomprehensible until you consider the historical process leading to them. Likewise for Rogers’ two examples. The absurdity of the giraffe’s laryngeal nerve or the human vas deferens are in no way mandated by other design constraints, and they are nothing even the world’s worst engineer would ever have dreamed up. Viewed as products of engineering they are ludicrous, but they fall right into place as soon you understand the evolutionary process that led to them. After a discussion of the giraffe’s laryngeal nerve, biologist Richard Dawkins aptly summarizes the situation: [I] soon realized that, where imperfection is concerned, the recurrent laryngeal is just the tip of the iceberg. The fact that it takes such a long detour drives the point home with particular 2.4 the complex structures argument 35 force. … But the overwhelming impression you get from scavenging any part of the innards of a large animal is that it is a mess! Not only would a designer never have made a mistake like that nervous detour; a decent designer would never have perpetrated anything of the shambles that is the criss-crossing maze of arteries, veins, nerves, intestines, wads of fat and muscle, mesenteries and more. To quote the American biologist Colin Pittendrigh, the whole thing is nothing but a ‘patchwork of makeshifts pieced together, as it were, from what was available when opportunity knocked, and accepted in the hindsight, not the foresight, of natural selection.’ (Dawkins 2009, 371) Living things possess many complex adaptations. Without exception, they show clear signs of having resulted from a lengthy, stepwise, historical process. They show the senseless signs of history. They are never pristine creations from nothing, as we might expect if they were designed by a powerful intelligence, but instead are invari- ably cobbled together from parts that are just lying around, so to speak. The concept is well illustrated by the various contrivances used by orchids to attract insects. Darwin made a comprehensive study of such structures, and he made the following observation (note that “homology” refers to the use of the same parts for different purposes in different species): If, indeed, [the reader] should care to see how much light, though far from perfect, homology throws on a subject, this will, perhaps, be nearly as good an instance as could be given. He will see how curiously a flower may be moulded out of many separate organs, – how perfect the cohesion of primordially distinct parts may become, – how organs may be used for purposes widely different from their proper function, – how other organs may be entirely suppressed, or leave mere useless emblems of their former existence. Finally, he will see how enormous has been the total amount of change the simple parental or typical structure which these flowers have undergone. (Darwin 1862, 289) 36 2 evolution basics Any other complex adaptation could be used to make the same point. For example, the flagellum used for propulsion by certain types of bacteria is composed of numerous proteins working together to carry out a definite purpose. In considering how such a structure might have evolved gradually, we are aided by the fact that nearly all of these proteins have other functions throughout the cell. Biochemist Ian Musgrave writes: [W]e now know that between 80 and 88 percent of the eubacterial flagellar proteins have homologs with other systems, including the sigma factors and the flagellins. Homologies between a few of the rod proteins and nonflagellar proteins have not been found yet, but they appear to be copies of each other and related to the hook protein. In the end, there is not much unique left in the flagellum. Download 0.99 Mb. Do'stlaringiz bilan baham: |
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