The Journal of Evolutionary Biology recently published a study by Smith et al, which used comparative anatomical and phylogenetic approaches to show that the human appendix is not just a vestigal remnant of our evolution, like the tailbone, but is in fact a functional aspect of our gastrointestinal system.
Following up on their original study two years ago, the research group reports that the appendix is now thought to act as a repository for the beneficial, symbiotic gut bacteria, so that in times of infection with 'bad' bacteria (ie: those causing diarrhea), the 'good' bacteria have a safe hiding place. When the infection passes, the 'good' bacteria can then spread out and repopulate the intestinal tract. This finding helps explain why the appendix has persisted in our anatomy through 80 million years or more.
Appendicitis, or infection of the apppendix, occurs when the appendix is blocked and bacteria inside over-multiply. If left too long, the appendix can burst. Appendices are routinely removed in cases of infection, with a reported lifetime risk of appendicitis in the USA of 8.7% in men and 6.7% in women (Addiss et al, 1990). This condition is now believed to occur mostly because our appendix does not need to work as hard as it did earlier in our evolutionary history, when we had less sanitation and more cases of ingesting 'bad' bacteria. The study's lead author suggests that the answer may lie in devising ways to challenge our immune systems today in much the same manner that they were challenged back in the Stone Age: "If modern medicine could figure out a way to do that, we would see far fewer cases of allergies, autoimmune disease, and appendicitis." (quote from Science Daily).
This research finding is also illustrative of one of the finer points of Darwin's hypotheses on evolution which was disproven as modern science and technology enabled the type of analyses not available in Darwin's era . Darwin believed the appendix was a remnant of the cecum, a digestive organ found in other animals, however this new data shows many animals with both a cecum and appendix.
Image from the NIDDK
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Michael Steinberg
doctorwascher
Paul Hinrichs
Mary Elizabeth Williams
Cary Tennis
Dave Cullen
Salon.com
Comments
ruicanuck, I'm not sure about that. I'm not a surgeon or immunologist seeing patients, so I wouldn't speculate about current medical practices. I wouldn't be surprised if alternative therapies develop given this new finding, however.