BOB HIRSHON (host):
Micro-microbiology. I’m Bob Hirshon and this is Science Update.
Listener Misha Salas-Winers from Rockville, Maryland, asked what the smallest living thing is. We turned to microbiologist Mike Conrad of the University of North Carolina at Chapel Hill. He says the smallest we know of is a parasitic bacterium called Mycoplasma genitalium. It’s about one five-thousandth of a millimeter in diameter.
MIKE CONRAD (University of North Carolina at Chapel Hill):
And some viruses can be much smaller, even, say, ten times smaller – like poliovirus is one of the smallest virues.
But many scientists don’t consider viruses to be true life forms, because they can’t do anything outside their hosts. If you’ve got a science question, big or small, call us at 1-800-WHY-ISIT. If we use it on the show you’ll win a Science Update mug. I’m Bob Hirshon, for AAAS, the science society.