From a dolphin’s mouth to the Atacama desert in Chile, microbes can turn up where scientists least expect them. Using DNA sequencing technology, a team of researchers recently published a new version of biology’s tree of life to include many of these elusive microbes. Microbiologist Karthik Anantharaman of the University of California, Berkeley says that these organisms just didn’t fit many of biology’s definitions.

"There’s a particular group of bacteria that we are calling the CPRs, or the candidate phyla radiation. And the common thread through all of these organisms is that they’re extremely tiny. So if we opened up any microbiology textbook today, they would tell you that the average size of a bacteria is about one micron. But these organisms are smaller than .1 microns. So they’re ten times smaller in diameter and a thousand times smaller in volume. And over the last 15 years, we have deciphered that biology can be very unpredictable."