SSS 2008-08-13（在线收听）

This is Scientific American's 60-Second Science. I'm Adam Hinterthuer. Got a minute?

Since so many species in a food web are interconnected, the demise of a one can mean extinction for several others that depend on it for food. Thanks to things like climate change and habitat destruction, this "bottom-up extinction" has ecologists scrambling to save key species. Stefano Allesino says they may just want to Google the problem.

Speaking on August 4th at the Ecological Society of America's annual conference, Allesino outlined a new way to rank the species of an ecosystem. Google uses a complicated algorithm to rank web pages that best match a query. Basically, a single webpage ranks low, but rises in importance if a handful of other pages link to it. The highest ranked sites have thousands of these well-connected pages linked to them.

Inspired by this system, Allesino’s formula gives importance to a species if it supplies food to another. And, if that species serves as food for several organisms, it climbs up the rankings. Higher ranked species, says Allesino, should become the focus of conservation efforts. And that means there's finally a perk to being the foundation of the food web.

Thanks for the minute for Scientific American's 60-Second Science. I'm Adam Hinterthuer.