Is there an evolutionary purpose to male pattern baldness? From what I’ve read, statistically. women prefer men with full heads of hair. The story of Samson is a good example of the age-old notion that lack of hair equals weakness and unattractiveness. Since most men will eventually go bald, how does that square with evolution’s incentive to survive and multiply?
The key to this is in understanding natural selection as a negative process rather than a positive process. In other words, the question is never “Is there an evolutionary value to this trait?” but “Is the absence of this trait detrimental to the species?”
And therein lies your answer: No. Male pattern baldness tends to develop after the peak breeding age of the male homo sapiens. So by the time his baldness might reduce his chances in the breeding pool, he’s quite likely already passed on his genes . . . including those for male pattern baldness. For the same reason, it would make no sense to ask if teeth that rot and fall out without modern dental care had an evolutionary purpose, or really an “symptom” of aging: they all come into play after the genes have already passed on, and thus have very little effect on the natural selection of the species.
This is already being discussed in another thread: Is there an evolutionary “purpose” to becoming feeble as we get older? I’ll close this one and direct further comment to the other thread.
As long as the men remain hair-covered until they find a mate and reproduce, later-life baldness has no bearing on reproductivity or what genes are passed on.
In fact, there be no “reason” for baldness, at all. It may be simply a genectic shift that occurred and that has survived by being passed on without causing any reason to select against the balding man.