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Complex Numbers #990304 added August 9, 2020 at 12:07am
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Wine, Cheese, and Bread
Today I get to talk about some of my favorite things.
https://www.smithsonianmag.com/science-nature/how-cheese-wheat-and-alcohol-shape...
How Cheese, Wheat and Alcohol Shaped Human Evolution
Over time, diet causes dramatic changes to our anatomy, immune systems and maybe skin color
You aren’t what you eat, exactly. But over many generations, what we eat does shape our evolutionary path. “Diet,” says anthropologist John Hawks, of the University of Wisconsin-Madison, “has been a fundamental story throughout our evolutionary history. Over the last million years there have been changes in human anatomy, teeth and the skull, that we think are probably related to changes in diet.”
Well, that doesn't mean I'm a pizza, no, but at least on a fundamental level, we know that we're made up of atoms taken from the substances we breathe and ingest.
I do have some issues with the way this article so cavalierly uses the word "evolution." I get the feeling an evolutionary biologist would have a cogent argument against it. I'm not one, so I'm just going to go with the flow here, for now.
When mammals are young, they produce an enzyme called lactase to help digest the sugary lactose found in their mothers’ milk. But once most mammals come of age, milk disappears from the menu. That means enzymes to digest it are no longer needed, so adult mammals typically stop producing them.
Thanks to recent evolution, however, some humans defy this trend.
Another interpretation: some of us retain childlike features. As should be apparent if you've been reading my stuff.
Hawks explains why being able to digest milk would have been such a boon in the past...
Speculation without supporting evidence. I mean, if you look at the article, the explanation makes sense, but I shy away from such just-so stories on principle. The facts are what they are; the explanation for the facts is suspect.
The article then goes on to talk about grains.
Since wheat and rye became a staple of human diets, however, we've have had a relatively high frequency of celiac disease. “You look at this and say how did it happen?” asks Hawks. “That's something that natural selection shouldn't have done.”
Translation: "I don't understand how natural selection actually works."
Yet despite the obvious drawbacks of celiac disease, ongoing evolution doesn't seem to be making it less frequent. The genetic variants behind celiac disease seem to be just as common now as they've been since humans began eating wheat.
That's because evolution doesn't care if an individual gets sick or has dietary limitations. Evolution only cares if someone lives long enough to reproduce. Well, I'm speaking metaphorically. Evolution neither cares nor doesn't care. It just is. Point is, unless there's something that kills people at an early age, the genes for it happily pass on. Okay, that's another metaphor. Genes don't feel happiness.
Then the author gets into the discussion of how diet could influence skin color, over time and in populations, which is kind of a minefield these days. Keep in mind it's not promoting any shade of skin as better or worse, in terms of evolution, than another, just describing what could have influenced skin tone changes in humans.
But then you get sentences like:
Mostafavi's genetic research also revealed that some variants that actually shorten human life, like one that prompts smokers to increase their consumption above smoking norms, are still being actively selected against.
Again: evolution is concerned with reproduction. Poor health outcomes from things like smoking or alcoholism don't tend to show up until later in life, after a human has had plenty of opportunity to reproduce (whether such habits influence the portion of the process of evolution called "sexual selection," I leave as an exercise for the reader). Point is, you can have some disease that kills you at, say, 30 or 40, but it doesn't stop you from having reproduced by then, so the genes that affect the expression of said disease aren't selected against.
So if there is indeed research on that subject, I hope it's peer-reviewed, because as it's presented here it certainly doesn't inspire any confidence from me.
Overall, I expected better from Smithsonian Magazine. |
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