A multicellular organism that lives without oxygen


You're looking at the first multi-cellular, anaerobic organism known to humans. Anaerobic, of course, means this little critter lives entirely without oxygen. We've long known that single-celled organisms could live this way, but this discovery comes as a bit of surprise. Even more fascinating (to me, at least) is the fact that this organism, part of a species called Loricifera, has no mitochondria. I didn't realize this, but anaerobic organisms have an entirely different organelle, called hydrogenosomes, that power their cells. I'm not sure whether hydrogenosomes have the same sort of origin story as mitochondria—i.e., separate organisms that took up residence in a host cell and became part of its machinery—but that's the first thing I'm researching tonight when I get a chance.