Forget the swallows. Why couldn’t evolution build US a better body?

I write about evolution a lot here, and there’s a good reason for that.  As Russian geneticist Theodosius Dobzhansky famously opined, nothing in biology makes sense without it.  But that doesn’t mean evolution itself makes sense.  It’s kind of a constant jury-rigging around a basic shape to adapt for ever-changing environmental conditions, whereas a lot of modern organisms would probably function a lot better if they were re-designed from the ground up.  Imagine throwing some snow chains and a plow on a Corvette and driving it through Alaska instead of just buying a goddamn truck like you ought to.  That’s pretty much how we got the bodies we have.  And subsequently why we hurt so much.

I’m talking about major morphological changes, not the shortening of a cliff swallow’s wingspan to better avoid speeding vehicles.  Evolution’s tinkering has taken us from lowly bacteria to the simplest swimming vertebrates and finally to the omni-talented bad-asses we are today (right?), but all that has come at a cost, which is most popularly documented in biologist Neil Shubin’s book, Your Inner Fish.  Besides humorous descriptions of how hernias form due to the weakness created in the abdominal wall by descending testicles (our ancestors didn’t have the temperature-finicky sperm that we do, so their gonads were safe within their bodies, while ours have to make the trek outside during development), he also offers a personal account of what a tragic junkyard the human knee is.  Our frequent knee problems are one symptom of a wonderful yet destructive innovation.

There are at least 12 competing hypotheses as to why man picked his knuckles up off the ground and decided to walk upright, but some advantages are tangible, such as raising the head for a greater field of vision and the freeing of the hands for other purposes, like using tools.  You can feel the negative consequences, too.  Besides knees, our ankles also tend to fall apart, but the worst disaster area is the human back.  The curves in our spines’ S-shape concentrate stress and can lead to scoliosis and spontaneously ruptured discs, a malady more or less unique to humans.  Taking a seat won’t eliminate the problem, either; it just shifts the stress concentration to the lower back.

Who thought THAT was a good idea?  From www.cedars-sinai.edu

Everyone knows we get obese because the tasty (and calorie-packed) treats we crave were harder to come by before we invented vending machines and McDonald’s, but even supposedly healthy stuff can harm our undeveloped constitutions.  While a staple in our current diets, we didn’t really start to eat wheat until the advent of agriculture, and we aren’t equipped with the proper enzymes to break down the gluten in today’s strains.  As much as 70% of humanity is lactose intolerant, as the practice of drinking milk really only became popular in Europe a couple thousand years ago.  Even tooth decay is a relatively recent blight, as the specific Streptococcus bacteria at the source may have jumped to our mouths from the rats that settled down with us in towns.

And there have been trade-offs for that big, beautiful brain of ours, the most noticeable of which is a woman’s wider pelvis, needed to push that mighty melon through.  Even then, babies are still faily helpless, and that protracted maturation period requires a huge amount of caretaking time from the parents.  A deal made within the brain itself was trading a better sense of smell for our increased color vision, as studies seem to show that we wouldn’t have been able to cram both into our craniums.  Frighteningly, the ability to bring all those brain cells into existence may also be what allows us to get cancer so frequently, as other animals don’t suffer it as often as we do.  People don’t undergo apoptosis (the process of killing malfunctioning cells, often heading off the rise of tumors) as much, which is great to allow the brain to burgeon, but not so good when something goes wrong and grows out of control.

WHAT DOES THIS MEAN?

Human beings are built as if you put a modern day, computerized automobile processing system into a Model T.  Great innovation, great performance in some areas, but not nearly as functional as if you just scrapped the old standard and designed a better frame altogether.  Our extended lifespans only further illuminate how cobbled together our bodies are, as the original engine really wasn’t meant to take us past 40.  Shit starts to break down, and we didn’t pony up for the extended warranty.  Too bad we’re stuck with what we’ve got and can’t just take the brand new ’14 Sapiens out for a spin.

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