Similar Needs, Similar Designs
Nova, the TV Science program aired on public broadcasting stations, presented an argument that human evolution is proven by the fact that, chemically, humans and apes are 99 percent alike. That argument has appeared many times, although very seldom in print. Dr. Duane Gish of the Institute for Creation Research answers it by pointing out that since a cloud is 99 percent water and a watermelon is 97 percent water, the watermelon must have missed being a cloud by only 2 percent!
Actually, the argument that there is only a 1 percent difference between man and apes assumes that we know a lot more about man and apes than we really do. And some of these comparisons can be very misleading. Some people have to take insulin, but does that come from our supposed distant cousin, the ape? No, beef cattle supply the nearest match to human insulin. When you have to have a new heart valve, does that come from the ape? No, it comes from the pig, the nearest match.
The old saying that statistics can be used to prove anything certainly applies to this evolutionary argument. The real reason that similar creatures often have similar chemical structures in their bodies is that creatures with similar bone structures tend to have similar needs and so have been given similar chemistry by the Creator.