Fri Feb 24 21:43:44 EST 2012
the pinnacle of evolution
(Attention conservation notice: Nothing said here is at all novel.)
So Maciej Cegłowski has updated his blog for the first time in four months. Upon encountering the novel task of "actually generating HTML", his gimcrack blogging software sprayed a couple random posts across his RSS feed, one of which was the venerable 2010 essay on scurvy in Antarctic exploration. Which, combined with some other things I've read recently, got me to thinking.
Vitamin C is just C6H806. Carbon, hydrogen, oxygen. All the atoms are there in glucose, just in a slightly different pattern. You could drink sugar water all day and never get scurvy, if we could synthesize it ourselves.
Except we can't, because ten million years ago a primate species discovered that they ingest enough vitamin C in the natural environment to get by without making it themselves.
A regular sideshow on my other blog is finding terrible Tumblr themes, then picking apart their CSS. I've learned a lot about CSS in the process, in the "gaze upon this disaster, young one, and learn well its lessons" sense. But even the most incompetently written theme isn't as poorly designed as vasopressin, which, among other things, controls:
- Water permeability of distal tubule and collecting duct cells in the kidney.
- Increasing permeability of the inner medullary portion of the collecting duct to urea by regulating the cell surface expression of urea transporters.
- Memory formation.
- Peripheral vasoconstriction as a response to blood loss from serious injury.
- Pair bonding.
The same hormone that controls your blood pressure also determines if you can form a relationship.
Homozygosity in allele 334 of RS3 is associated in men (but not women) with problems with pair-bonding behavior, measured by traits such as partner bonding, perceived marital problems, marital status, as well as spousal perception of marital quality.
In a study of 203 male and female university students, participants with short (308-325 bp) vs. long (327-342) versions of RS3 were less generous, as measured by lower scores on both money allocations in the dictator game, as well as by self-report with the Bardi-Schwartz Universalism and Benevolence Value-expressive Behavior Scales; although the precise functional significance of longer AVPR1A RS3 repeats is not known, they are associated with higher AVPR1A postmortem hippocampal mRNA levels.
Who the fuck designed this? The answer is, of course, "nobody". The blind idiot god of evolution cares not at all for separation of concerns, or design elegance, it just cares about how many offspring are produced. For evolution, the person who died at the age of 29, with six children, and the person who lived for two hundred years and won six dozen Nobel prizes, but never had children, it considers the latter person to have failed.
It's even a mistake to think of evolution as an "entity" with "intent" or "purpose": evolution is the simple historical fact that the genes of the organisms which produce more offspring are more frequent in the general population. And so we have white blood cells that trigger diabetes when they don't have parasites to combat, or the thousand and one autoimmune diseases of an environment that is too clean: the blind flailing of an immune system fighting a battle that's already won.
The human body is the ultimate tangle of dependencies, nobody sat down with a clean sheet of paper and said, "Alright, I'll design this anthropomorphic replicator so that bacteria outnumber the endogenous cells 10 to 1." No, of course not! But bacteria were endemic in the ancestral environment, and so they colonized the human body, just as they've colonized every square millimetre on the entire planet.
It's almost amusing to watch the naturists try to spin this, as if it's a good thing that fully 30% of fecal mass is bacteria! You had to eat that food, yet it's being wasted on making bacteria. A prime example of local maxima. You could imagine a mutant human with stomach enzymes that could digest oligosaccharides itself, without needing bacteria-- but the bacteria are already there. There's no fitness advantage, all paths lead down from there, and evolution has no foresight. You need two unlikely mutations to occur in the same individual at the same time (oligosaccharidease and an immune response to whatever oligosaccharide bacteria we already use) to acquire a fitness advantage, and that coincidence will be vanishingly rare.
A pretty safe bet is that two hundred years from now, the idea of "vitamins" will be a quaint anachronism. Having to consume minerals is going to be with us for a while, barring really surprising breakthroughs in nuclear reactor miniaturization; but the need to periodically ingest acorbic acid is a bug, which will be patched sooner rather than later.
EDIT: There were about a dozen comments calling out how terrible this post looked on mobile browsers. Sorry, guys! Fixed.