There’s a great article over at RichardDawkins.net about some of the history of our development through evolution. It explains how some of the common conditions and ailments we suffer from are the results of humans being descended from other life forms:
Our humanity comes at a cost. For the exceptional combination of things we do—talk, think, grasp, and walk on two legs—we pay a price.
This is an inevitable result of the tree of life inside us. Imagine trying to jerry-rig a Volkswagen Beetle to travel at speeds of 150 miles per hour. In 1933 Adolf Hitler commissioned Dr. Ferdinand Porsche to develop a cheap car that could get 40 miles per gallon of gas and provide a reliable form of transportation for the average German family. The result was the VW Beetle. This history, Hitler’s plan, places constraints on the ways we can modify the Beetle today; the engineering can be tweaked only so far before major problems arise and the car reaches its limit.
In many ways, we humans are the fish equivalent of a hot-rod Beetle. Take the body plan of a fish, dress it up to be a mammal, then tweak and twist that mammal until it walks on two legs, talks, thinks, and has superfine control of its fingers—and you have a recipe for problems. We can dress up a fish only so much without paying a price. In a perfectly designed world—one with no history—we would not have to suffer everything from hemorrhoids to cancer.
Nowhere is this history more visible than in the detours, twists, and turns of our arteries, nerves, and veins. Follow some nerves and you’ll find that they make strange loops around other organs, apparently going in one direction only to twist and end up in an unexpected place. The detours are fascinating products of our past that, as we’ll see, often create problems—hiccups and hernias, for example. And this is only one way our past comes back to plague us.
It’s a good read and I encourage you to go read it in full. It’s this sort of breadth of knowledge that the Theory of Evolution has provided us that just shoots holes in the so-called Intelligent Design alternative explanation. An all-powerful, all-knowing God would’ve done a much better job of designing humans than what we see in ourselves. Either that or he’s not as all-knowing as he likes to think he is.