Scientists at the University of California, Los Angeles, say they've discovered a microorganism that hasn't evolved in more than two billion years -- the longest-ever absence of evolutionary behavior in a single species.
Researchers say the deep sea creature -- whose evolutionary stasis is detailed in the journal PNAS -- doesn't disprove evolution so much as bolster Darwin's case.
"The rule of biology is not to evolve unless the physical or biological environment changes, which is consistent with Darwin," lead study author J. William Schopf, a professor of earth, planetary and space sciences at UCLA, explained in a press release.
"These microorganisms are well-adapted to their simple, very stable physical and biological environment," Schopf said. "If they were in an environment that did not change but they nevertheless evolved, that would have shown that our understanding of Darwinian evolution was seriously flawed."
Schopf and his colleagues used a variety of spectroscopic imaging techniques to study sulfur bacteria fossils embedded in deep sea rocks of varying ages. Analysis of the microorganisms from 1.8 billion-year-old rocks from Western Australia and 2.3 billion-year-old rocks collect off the coast of Chile proved that ancient sulfur bacteria looks the exact same now as it has for more than two billion years.
Schopf says it is certainly fascinating (and perhaps, unexpected) that some types of life haven't evolved for nearly half the history of the planet Earth, but that the discovery fits perfectly with Darwin's ideas.