Researchers have found a type of bacteria in California's Mono Lake that substitutes arsenic for phosphorous. Arsenic is normally a deadly element for terrestrial life, and phosphorous is normally required. Because of the high arsenic content of Mono Lake, the bacteria managed to substitute one for the other to survive, and now thrives on it. It's the equivalent of finding life based on silicon instead of carbon.
The ramifications are that life can be much more plentiful than ever dreamed of, except in science fiction, taking advantage of any conditions thought to be anathemic to it. It pushes the expectation that life can be anywhere more toward one that life will be anywhere, that a world is much more likely to have life than thought possible. Another recent determination that there are three times as many stars as previously thought even more greatly expands the living universe.
This could also be a problem for those who reject evolution, as it shows that natural selection is responsible for the bacteria's survival and is an ongoing process.