A couple of weeks ago, the New York Times Magazine published its 2007 “Year in Ideas” issue — their annual compendium of the year’s most interesting and offbeat research. I wrote up five of their scientific and technological entries. The entire issue is online here for free, but I’m also archiving my pieces here for posterity’s sake.

This one’s about a new theory for why the appendix exists! That lovely image above, by Bryan Christie Design, accompanied it.

The Appendix Rationale

For years, the appendix got no respect. Doctors regarded it as nothing but a source of trouble: It didn’t seem to do anything, and it sometimes got infected and required an emergency removal. Plus, nobody ever suffered from not having an appendix. So human biologists assumed that the tiny, worm-shaped organ is vestigial — a shrunken remainder of some organ our ancestors required. In a word: Useless.

Now that old theory has been upended. In a December issue of The Journal of Theoretical Biology, a group of scientists announce they have solved the riddle of the appendix. The organ, they claim, is in reality a ”safe house” for healthful bacteria — the stuff that makes our digestive system function. When our gut is ravaged by diseases like diarrhea and dysentery, the appendix quietly goes to work repopulating the gut with beneficial bacteria.