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Links With Your Coffee - Wednesday


  • Human Culture, an Evolutionary Force
    As with any other species, human populations are shaped by the usual forces of natural selection, like famine, disease or climate. A new force is now coming into focus. It is one with a surprising implication — that for the last 20,000 years or so, people have inadvertently been shaping their own evolution.

  • How to Buy a Gift for an Old Man
    Young people are always going on about how difficult it is to buy presents for their older relatives. While I’m not sure I would agree that seniors are hard to shop for, I fully agree that we tend to get really crappy gifts.

    For the most part, the presents given to old people fall into one of two categories. The first – and most popular – is what I affectionately refer to as “Stuff I Already Have 10 of, God Damn it.”

  • Rethinking the Shopper's High: New Ways to Get the Rush Without Laying Out the Cash
    The serotonin release from the sport of shopping (think runner's high spiked with chic Milly dresses and swank Boss suits) can be attained from trying and not buying. I know; I'm an addict who has been successfully practicing restraint for months now, spurred on by a schizophrenic personal portfolio and a renewed commitment to green frugality.

  • Study Links Religion and Racism
    In general, the more devout the community, the greater the racism, according to the authors of the analysis, led by Wendy Wood, Provost Professor of Psychology and Business at USC College and the USC Marshall School of Business. The study appears in the February issue of Personality and Social Psychology Review.

  • Community Organized
    Last week I heard an apologist for business interests refer to people concerned about global warming as “the alarmist community.” Then on Sunday an innocuous post about gluten on Dining@Large yielded an increasingly strident series of comments, one by a person self-identified as a member of the “gluten free community.” *

    I do not speak on behalf of the language usage community but for myself when I say that I am mildly disturbed and to a greater degree annoyed by this vogue for identifying single-issue groups as a “community.” **

    Community and common are etymologically related, and I understand that people who suffer from a disorder have common interests and concerns. But community suggests, or ought to, something broader.



Great article on evolution and culture but...I feel kind pretty dense on some of it. I think I don't quite get what constitutes "culture." With what people eat, is that cultural or necessitated by access? If a wolf mainly had access to rabbits because that's what the area offered although they would eat other small animals given the opportunity, that doesn't make it cultural, does it? So, if milk was the most readily accessible source of food - would that make it cultural? Like I said, I'm being dense here...

Well, you have to know the mammal pretty well for it to let you drink its milk :)

Seriously, the cultural aspect is the farming of animals, and then learning to collect the milk for consumption (a trait that is passed down to others by observation, communication, copying, etc). These are all examples of cultural (rather than genetic) evolution.

The genetic aspect is the evolution of increased ability to properly digest that milk. The cultural changes must have preceded the genetic ones (at least at a population level - see below).

The thing I find interesting here is the fact that there are 4 different genetic variants in 4 different human populations in which lactose tolerance has evolved. This suggests that ancestral populations did not have any variation for this trait (if they did, then different descendant populations would likely have the same variants; they don't, which suggests de novo mutations in each of the four populations, three of which are in Africa).

So the mutations arose de novo and then were selected for in the four different populations. But this is the thing that I find to be the most interesting possibility: what if the selection pressure of the pastoral society somehowdirected or induced the mutation to occur?

Now, most biologists would pounce all over that suggestion. It's Lamarckian- there's no good evidence for that!

Well, there is starting to be some evidence that Lamarck may have been partially right - in a limited sense (not in the sense of the giraffe reaching for the leaves and passing it on to it's kids, though).

But this idea of de novo mutation is actually more like something codified later, and mostly forgotten by biologists. It's called the Baldwin Effect. Experience increasing the likelihood of certain variants arising.

[and look! there's the Lactose example in the wiki :) ]

In the early 50's Conrad Waddington kind of went in the same direction with his genetic assimilation concept, but appeared to back away from the harder-core Baldwin Effect-like ideas in later publications. Who knows? Maybe from pressure from his skeptical colleagues?

Anyway, it seems to me that this is testable. If the de novo mutations arose totally by chance in these 4 populations, then such lactose-tolerance variants should be present in other populations as well (it's just that they haven't been selected for; but they should be there, cryptically, presumably at very low frequency).

BUT...if the de novo mutations arose by a Baldwin Effect-like mechanism, then the variants would not be found - even cryptically - in other populations, except by migration from these 4 populations in question.

Will be cool to see how that turns out. Baldwin's vindication day may yet come! :)


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