The development of any adaptation in an organism serves only one ultimate purpose: reproduction. The creatures more able to reproduce pass their genes along to subsequent generations in greater numbers. It’s not just about being a raging stud, sometimes the key is a longer life (more chances to mate) or better food gathering skills (surviving adverse conditions). But the key thing is that over time, less successful creatures produce fewer sexually mature offspring, whose genetic inheritance puts them at a disadvantage, and this disadvantage is eventually weeded out of the gene pool by attrition.
Some of the attributes we have acquired through natural selection seem arbitrary: why, for example, do we have ten fingers? Because we can lose a few and stay alive to reproduce, that’s why. If we only had two, one minor chainsaw accident would put us out of the food gathering business. Growing and learning to use twelve fingers probably consumes too much of our resources during childhood, so evolution decided it was too many. But of course, that decision was made before the development of the chainsaw.
You may have noticed that a man’s penis is located a pretty good distance from his brain. In the event of an accident or an attack, a man could lose his penis and live to a ripe old age, although his surviving brain would contemplate suicide hourly. It seems only logical that the brain and the penis should be joined together, because losing either of them puts you out of the running, genetically speaking.
So why did this happen? Why did evolution separate the brain and the penis? A creature that loses its penis is the most disadvantaged of all, because it can no longer reproduce. Instead, it consumes resources that would otherwise be available to its still-reproducing neighbors.
It seems reasonable that at some point (far, far in the distant past when our ancestors were still wormlike muck-dwellers), a creature with a united penis-brain (the Penis Brain Worm) would have emerged. This creature would have no advantage over those with a separated brain and penis (the Separated Penis Worm). However, consider the following two scenarios:
- A Giant Slimy Tooth Worm bites the penis off of Stanley, a Separated Penis Worm. The neighbors notice no difference in their quality of life. The same amount of food is available. Sure, Stanley seems depressed, but the Hendersons are having a party and life is too short to hang around with guys like Stanley.
- A Giant Slimy Tooth Worm bites the penis-head off of Richard, a Penis Brain Worm, who instantly dies. Nobody misses Richard, because most people think he was having an affair with Stanley’s wife anyway. The neighbors notice more food is available, and begin to have more parties. In fact, the neighbors start nudging the surviving Penis Brain Worms in the direction of the Giant Slimy Tooth Worm.
So there’s no advantage to logical design. Good thing, too. I can’t imagine what my clothes would look like if the Penis Brain Worm had survived.