The Function of the Appendix

In “The Appendix: Useful and in Fact Promising,” (LiveScience; posted: 24 August 2009 07:05 am ET)  Charles Q. Choi writes:

Parker and his colleagues recently suggested that the appendix still served as a vital safehouse where good bacteria could lie in wait until they were needed to repopulate the gut after a nasty case of diarrhea. Past studies had also found the appendix can help make, direct and train white blood cells. Now, in the first investigation of the appendix over the ages, Parker explained they discovered that it has been around much longer than anyone had suspected, hinting that it plays a critical function. “The appendix has been around for at least 80 million years, much longer than we would estimate if Darwin’s ideas about the appendix were correct,” Parker said. Moreover, the appendix appears in nature much more often than previously acknowledged. It has evolved at least twice, once among Australian marsupials such as the wombat and another time among rats, lemmings, meadow voles, Cape dune mole-rats and other rodents, as well as humans and certain primates. “When species are divided into groups called ‘families,’ we find that more than 70 percent of all primate and rodent groups contain species with an appendix,” Parker said. © Imaginova Corp. All rights reserved.