The argument goes something like this: Why would a perfect Designer (like the God of the Bible) create imperfect designs?
In general, the Christian response to these examples is to say that these so-called poor designs or "useless" organs do actually have some kind of purpose or function, we may just not have discovered it yet. This has certainly proven true with things such as the panda's thumb and junk DNA. (For an update on the panda's thumb issue, see also the Today's New Reason To Believe from February 25, 2006. You'll have to scroll down to the right date.)
This week, scientists announced a new theory about the function for the human appendix.
Scientists: Appendix Protects Good Germs
Some scientists think they have figured out the real job of the troublesome and seemingly useless appendix: It produces and protects good germs for your gut. That's the theory from surgeons and immunologists at Duke University Medical School, published online in a scientific journal this week.
For generations the appendix has been dismissed as superfluous. Doctors figured it had no function, surgeons removed them routinely, and people live fine without them...
The appendix "acts as a good safe house for bacteria," said Duke surgery professor Bill Parker, a study co-author. Its location - just below the normal one-way flow of food and germs in the large intestine in a sort of gut cul-de-sac - helps support the theory, he said.
Also, the worm-shaped organ outgrowth acts like a bacteria factory, cultivating the good germs, Parker said.
That use is not needed in a modern industrialized society, Parker said. If a person's gut flora dies, they can usually repopulate it easily with germs they pick up from other people, he said. But before dense populations in modern times and during epidemics of cholera that affected a whole region, it wasn't as easy to grow back that bacteria and the appendix came in handy.
In less developed countries, where the appendix may be still useful, the rate of appendicitis is lower than in the U.S., other studies have shown, Parker said.