Red hair. Freckles. Pale skin. Soulless. What good are they?

Seriously — I have a red-haired son and brother and cousins, and you’ve got to wonder why evolution has spawned all these strange color variants — there’s no known advantage to ginger-ness, and plenty of disadvantages.

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I’ve been working up a science talk for the fall — I am going to do a basic review of many the mechanisms other than selection that contribute to evolution for lay audiences. And then I discover that T. Ryan Gregory has already done some of the work for me.

Maybe I should just plagiarize it?

(No, not really: my talk is less genomics, more development, and gets more basic than this one. But Gregory’s talk is very, very good.)

(via Sandwalk.)

I found this very satisfying: Steven Pinker summarizes all the problems with group selection. It’s a substantial essay, but if you just want the gist of it, here’s the conclusion.

The idea of Group Selection has a superficial appeal because humans are indisputably adapted to group living and because some groups are indisputably larger, longer-lived, and more influential than others. This makes it easy to conclude that properties of human groups, or properties of the human mind, have been shaped by a process that is akin to natural selection acting on genes. Despite this allure, I have argued that the concept of Group Selection has no useful role to play in psychology or social science. It refers to too many things, most of which are not alternatives to the theory of gene-level selection but loose allusions to the importance of groups in human evolution. And when the concept is made more precise, it is torn by a dilemma. If it is meant to explain the cultural traits of successful groups, it adds nothing to conventional history and makes no precise use of the actual mechanism of natural selection. But if it is meant to explain the psychology of individuals, particularly an inclination for unconditional self-sacrifice to benefit a group of nonrelatives, it is dubious both in theory (since it is hard to see how it could evolve given the built-in advantage of protecting the self and one’s kin) and in practice (since there is no evidence that humans have such a trait).

Group selection is one of those ideas people succumb to all the time…but it’s also a fringe concept that demands really good evidence before anyone should believe it, and no one seems to be able to come up with any.