It is a reasonable idea, particularly under the proposed model, that the inherited wrinkling or furrowing patterns on the skin, as on the brow or the back of the neck in humans, are vestiges of a condition in which these patterns were more distinct and reptilian, more clearly reflecting a primitive segmented state. Is it a consolation to think that we are not wrinkling up amorphously, like prunes, but that we are just proceeding throughout life toward a more complex anatomy, as our truncated ontogeny edges toward a reptilian condition that was fully realized in an earlier era?
The lines of flexure on the digits, the palms, the soles of the feet, and behind various joints, may also be viewed as vestiges of a primitive condition of distinct segmentation. Otherwise, these lines are puzzling, as they appear in the embryo, before any actual flexure could have created them. It may be argued that Darwinian evolution created these lines in appropriate places, giving a crucial advantage over competitors who lacked pre-creased skin covering their joints; but this is difficult, like maintaining that the symmetrical stripes of the zebra evolved through the gradual selection of random markings.
Darwinian evolution is plausible as a means of distorting organic structures; but to explain complex symmetrical patterns, something else is needed, some specific subsidiary mechanisms.
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