Peter Frost on Nordic Hair and Eye Colour Diversity By Brian Simpson
Europeans are the exception to the rule of humans having one hair and eye colour, not only having black hair, but all shades right down to white blonde. Why? Peter Frost addressed this issue, and I will take issue with him:
Frost rightly rejects the hypotheses such as natural selection to ensure vitamin D reserves, intermixture with Neanderthals, genetic drift, founder effects, and other random processes. His explanation is sexual selection:
“For some, including the geneticist Luigi L. Cavalli-Sforza, the answer is sexual selection. This mode of selection intensifies when males outnumber females among individuals ready to mate, or vice versa. The sex in excess supply has to compete for a mate and resorts to the same strategies that advertisers use to grab attention, such as the use of bright or striking colors.
In other animals, bright colors are usually due to sexual selection. Sometimes the result may be a "color polymorphism" (see box). A potential mate will respond not simply to a bright color but also to a rare one that stands out from the crowd. By enhancing reproductive success, however, such a color will also become more common and less eye-catching. Sexual attraction will then shift to less common variants, the eventual result being an equilibrium that maximizes color diversity. …
but why is hair and eye color so much more diverse in Europe than elsewhere? Perhaps because sexual selection was much stronger among ancestral Europeans than in other human populations.
Sexual selection intensifies when the "Operational Sex Ratio" (OSR) ceases to be balanced, i.e., when too many of one sex are competing for too few of the other. To understand why this may have happened in ancestral humans, we can examine the demography of present-day hunter-gatherer bands. Such groups usually develop an OSR imbalance for two reasons: 1) hunting distances are longer and have increased the death rates of young men, typically because game animals are more mobile and/or less numerous per unit of land area; and 2) the cost of providing for a second wife is higher and has reduced the incidence of male polygamy (polygyny), typically because women are procuring less food for themselves through food gathering. As a rule, OSRs are less balanced further away from the equator. In the Temperate Zone, and even more so in the Arctic, game animals roam over larger territories and gatherable food is less available in winter.
The most extreme OSR imbalance occurs among hunting peoples of the "steppe-tundra," where almost all consumable biomass is in the form of highly mobile and spatially concentrated herbivores such as caribou, reindeer, or muskox. On the one hand, men die younger because they have to cover long distances in search of herds, with no alternate food sources. On the other, men are less polygynous because they bear almost the full cost of feeding their families in a habitat that offers women little opportunity for food gathering. With fewer men altogether and even fewer polygynous ones, women have to compete for a limited supply of potential husbands.”
This, though, is yet another evolutionary “just so” story, based upon speculation that feels right. How do we know sexual selection occurred? The sexual selection hypothesis requires that the actual characteristics exist first, so that they can be selected by discriminatory sex selection, and from that point natural selection continues. But this does not explain how those different forms arose in the first place. All conventional biology has is random genetic mutations, but Frost has rejected randomness as an explanatory hypothesis.
My explanation? I am inclined to go with special creation here, that something of beauty was created by the Divine to add some colour into a pretty savage world. That is not science, but to hell with science!