Evolutionary Theory Not Even Skin Deep

A book on skin just was published – no, not one of those books, but a book on the physiology of human skin.  Nina Jablonski wrote Skin: A Natural History (UC Berkeley, 2006) and Qais Al-Awqati (Columbia U) reviewed it in Science.¹  The reviewer noticed that “In its discussion of the human skin, the book’s principal theme is evolution, and almost every page contains that word.”  So, how did Jablonski do?  Did she satisfy the reviewer’s hopes that Darwin can explain the naked ape?

Although the author wants to provide an evolutionary perspective on all attributes of skin biology, the accounts she provides seldom rise above the provision of plausible hypotheses.  Is it really true that we were selected to be hairless sweaty creatures?  That sounds possible, but what is the actual evidence for such an assertion?  Is it also true that vitamin D synthesis, a major locus of interaction between sunlight and diet, is the dominant factor in the natural selection of skin color?  This idea is simply presented without any of the documentation that would make a convincing story.  One would like to see the evidence of how rickets (vitamin D deficiency) might act as an agent of evolutionary selection.

Even in the areas of sociology, “The thorny issue of the social construction of the roles of skin color is reduced again to a brief survey of skin color biology and its evolutionary implications.”  At the end of the review, Al-Awqati tried to find a few things to praise, but the shallowness of Jablonski’s evolutionary theorizing extended to her own research.  “Although only a few of Jablonski’s research papers address skin evolution,” he said, “the lack of deep expertise need not prevent a nonspecialist from pulling together findings from different fields to generate an exciting, even fresh view of nature.”  Apparently this book “fell short” of this mark also.

¹Qais Al-Awqati, “Anthropology: Showing Some Skin,” Science, 2 March 2007: Vol. 315. no. 5816, p. 1223, DOI: 10.1126/science.1138921.

If even a fellow evolutionist comes looking for evidence for evolutionary myths and can’t find it, why should anyone else pay attention?  It’s not just the sociology of skin that is Darwin’s thorn in the flesh.  Heat regulation in furry apes is much different than the sweating response in human skin.  Sweat glands are complex structures under the control of the nervous system.  The skin is not just a surface; it has multiple layers with veins, arteries, glands, nerves, hair muscles, sebaceous glands, pores and specialized receptors for touch, heat and pain.
    Werner Gitt in The Wonder of Man says that one square centimeter of skin contains 6 million cells, 100 sweat glands, 15 sebaceous glands, 5,000 sensory corpuscles, 200 pain points, 25 pressure points, 12 cold-sensitive points and 2 heat-sensitive points.  Skin sloughs off dead cells while regenerating new ones in a precise balance.  It is an important barrier to disease germs, and a protection from injury and dehydration.  It performs a respiratory function, absorbing some of the oxygen we use, while letting some carbon dioxide in and out.
    Human skin is an incomparable substance.  Burn victims are not given artificial plastics; they are given skin transplants from live humans.  How does evolution explain the fact that a newborn infant arrives into the world with a vernix coating to protect its skin?  What evolutionary process led to the precise timing of a multitude of changes that occur in the right sequence when a baby is born?  These are all matters of life and death; without them, there would be no human race.
    These observational facts demand causes equal to them.  Creationists have no problem with the question.  Jablonski wrote a whole book on the theme of skin evolution, mentioning the E word on practically every page.  The reviewer was itching for evidence, but only received rash excuses.  Scratch that.