Map of life expectancy at birth from Global Education Project.

Sunday, August 13, 2006

I believe it, and that settles it

I note that some commenters have taken to calling others "trolls." According to my Random House Unabridged Dictionary, a troll is "(in Scandinavian folklore) any of a race of supernatural beings, sometimes conceived as giants and sometimes as dwarfs, inhabiting caves or subterranean dwellings." So, that allegation seems improbable to me. I'm pretty sure these beings are mythical. Anyway, regardless of whether any of our commenters are supernatural beings from Scandinavian folklore, as I said before, no ad hominem (or ad supernaturalbeingem) attacks please. People are allowed disagree with the host here -- although threatening or otherwise antisocial comments will be deleted.

For example, I note that a commenter attributes hydrogen bonds to cheese from the Flying Spaghetti Monster's noodly appendage. This is a damnable heresy, but I stay my hand from smiting the heretic. Hate the sin, love the sinner, as they say. The truth is that the FSM is sauced with marinara, with the merest sprinkling of cheese. (Plenty of pepperoncini, however, the holy Spice of Life.) Hydrogen bonds are likely the consequence of starchiness, not cheesiness.

Finally, a commenter doesn't care how old the world is, because how is that going to prevent him from getting diabetes? Actually, I started this whole thing precisely because it will! Understanding evolution, which in turn is only possible within the context of geological time, is essential to keeping ourselves healthy. My initial point had to do with drug resistant pathogens, but I am planning to end the series on evolution with a discussion of Type 2 diabetes.

Let me take this opportunity, however, to say something briefly about Type 1 diabetes. Diabetes is actually the name for a symptom, not a disease, and there are two main diseases that cause diabetes, known as Type 1 and Type 2. (There is also gestational diabetes, during pregnancy, and some less common conditions.) Type 1 is an autoimmune disorder in which the immune system mistakenly attacks the pancreatic cells which produce the hormone insulin. Insulin is signals the body's cells to absorb the sugar glucose, the cellular fuel, from the blood stream. (Our cellular endoymbionts, the mitochondria, descendants of ancient bacteria, do the job for us of burning the fuel.) Without insulin, the cells starve.

(Type 2 diabetes is a metabolic disorder related to overweight, physical inactivity, and high proportions of sugars and simple starches in the diet with low fibre. In Type 2 diabetes, the cells stop responding properly to insulin. More on this later.)

Type 1 diabetes, like other autoimmune disorders such as rheumatoid arthritis, lupus, and multiple sclerosis, is a pretty good argument against intelligent design. The immune system evolved to protect the body against microparasites that would otherwise eat us alive. But sometimes it gets bollixed up and starts attacking tissues of the self as well as foreign invaders. Like everything else about us, it developed in small steps, by trial and error, and so it is only as good as it happens to be. It is impressive, but far from perfect. It's easy to think of ways to design an immune system that won't make that sort of mistake, just as we could design a birth canal that isn't too small for the baby's head, or a spine that is properly designed for an upright posture instead of the jury-rigged system we have that gives so many of us chronic back pain and sciatica.

But we aren't designed. Tough luck.

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