Biology/biology
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Question
Why do black people have less melanin in the skin of their palmar and plantar surfaces than elsewhere?
Dear Gerald,
This is an interesting question, and I don't think anyone can give a definitive answer. Is there an adaptive reason for the lack of melanin on those surfaces? I'm hard-pressed to think of one!
As you probably know, any trait can be:
1. adaptive (increases the individual's likelihood of leaving offspring)
2. maladaptive (decreases the individual's likelihood of leaving offspring)
3. neutral (does not affect the individual's likelihood of leaving offspring)
I cannot think of any adaptive reason that pale palms and soles would be an adaptive advantage. So I would ascribe this to what Stephen Jay Gould would call an "epiphenomenon": a trait that exists for no known reason, but has not been an evolutionary disadvantage, and so is maintained in the population.
It may simply be that when the DNA encoding our pigmentation patterns evolved, there simply was no mutation that encoded dark palms.
It's an interesting question, but I'm not sure it has an evolutionary answer.
Wish I could give you one! :)
Dana
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| Rating(1-10) | Knowledgeability = 7 | Clarity of Response = 9 | Politeness = 10 |
| Comment | Thank you for responding so candidly. Since she [he?] did not know the answer I cannot grade a 10; on the other hand, the implication is nobody does, so it's not right to give a zero or similar. I'll keep looking elsewhere, however. | ||
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Answers by Expert:
Dana Krempels, Ph.D.
Expertise
I can answer biology-related questions in the areas of evolution, zoology, botany, genetics, and ecology. But I don't answer homework questions or provide ideas for your science fair projects. So students please do your learning the right way by reading your text assignments and studying!
Experience
At the University of Miami, I teach Evolution and Biodiversity, Botany, Zoology, Genetics, Ecology, and a variety of seminars (e.g., the Biology and Evolution of Human Gender Roles).
Education/Credentials
I have a B.S. in Biology and an A.B. in English from the University of Southern California (1980).
I earned my Ph.D. in Biology in the area of evolutionary biology/visual physiology from the University of Miami in 1989.
Past/Present Clients
I am currently an "expert" in both the "Rabbits" and "Wild Animals" categories.
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