Theories differ over functions of vestigial organs

Jim Trimble remembers his appendix only as a source of extreme pain.

Trimble, who was born in Florence and now lives in West Point, N.Y, remembers the Monday, seven years ago, when his appendix started to bother him. By Thursday, he was in surgery to remove the ruptured organ that had swelled to the size of a softball.

"Had it not ruptured, I probably would not have considered it at all," he said.

That's how it is with most body parts: they aren't really noticed until they give us a problem.

Now, some researchers are theorizing whether many of our body parts are really needed.

In 2007, Duke University researchers concluded that the appendix, a tiny bag-like organ attached to the intestine, may be a safe place to store bacteria that helps digestion, but it is an organ that many animals do not have.

There are reportedly 180 vestigial organs, those typically considered to be useless evolutionary artifacts. The list includes tonsils, gallbladder and the tailbone, all body parts that Trimble still has, by the way.

Now that he's without his appendix, however, Trimble said he's not sure how the organ functioned in the first place.

"It doesn't feel any different, and I don't think my health has been any different after having it removed," he said.

The question of whether vestigial organs provide a function or serve as evolutionary curios has been around almost as long as the organs themselves.

Mention the word "evolution" and Charles Darwin comes to mind. He wrote "The Origin of Species," a seminal work on evolution that was published in 1859. He argued that vestigial, or rudimentary organs, that were once functional, became useless as the body evolved and the organs were no longer needed.

It's a theory researchers still are arguing over almost 150 years later.

William Parker, assistant professor of experimental surgery at Duke University, who conducted the collaborative analysis, said modern issues with appendices may come from our hyper-hygenic world. The analysis was published in December in the Journal of Theoretical Biology.

For instance, when we encounter disease-causing parasites and organisms, our underexposed and thereby sensitive immune system overreacts and causes the appendix to inflame.

"Thus, our modern health-care and sanitation practices may account not only for the lack of a need for an appendix in our society, but also for much of the problems caused by the appendix in our society," Parker said.

Some conclude that vestigial organs can debunk the theory of evolution itself. In a study published in 1981, S.R. Scadding, now a researcher at the University of Guelph in Canada, argued that vestigial organs invalidated evolution.

"Since it is not possible to unambiguously identify useless structures, and since the structure of the argument used is not scientifically valid, I conclude that 'vestigial organs' provide no special evidence for the theory of evolution," Scadding wrote.

No matter how the debate plays out in scholarly circles, the question remains: Should people laser remove their hair, cut off their tailbones and schedule appendectomies?

"Everything in the body is connected to everything else. If you don't know what part an organ plays, then consequences (of an organ's removal) can be far-reaching," said Amy Crews, associate professor of Biology at the University of North Alabama who is teaching anatomy this semester.

She suspects that human anatomy has already undergone some basic evolutionary processes, but we're not likely to see anything new within our lifetimes.

"I expect if you go back and look at early humans, you can look at the skeleton and see it looks somewhat different than we do," she said.

Crews pointed out that the gallbladder is an accessory part of the digestive system, and the appendix plays a role in the body's immunity.

James M. Cheverud, professor of evolution at Washington University in St. Louis, agreed that eliminating one organ during development may have repercussions to other organs.

For example, the "notochord," which evolutionists believe is one of the earlier versions of a backbone, plays a vestigial role in human adults since it becomes the gel in the middle of a spinal disc and can become herniated, what's commonly known as a slipped disk.

"While it may seem vestigial in adult function, it plays a crucial role during development," said Cheverud. "If we didn't have the notochord, we wouldn't live." That's because one of the many functions of the notochord is to develop our spines, nervous system and body length in the embryo.

For other organs such as the appendix, Cheverud said, "These do function in trying to eliminate infection; it's really when they fail in their task when there is a problem."

Cheverud added that for many organs, "Whether there is a function, that is a tough question."

For appendix-free Trimble, that question has an easy, though unscientific, answer.

The only artifact that remains from Trimble's appendix is a six-inch scar across his belly.

"Without being qualified as medical doctor," said Trimble, "I don't see any reason why we need an appendix."

Michelle Rupe Eubanks can be reached at 740-5745.

Trevor Stokes can be reached at 740-5728.