All life on Earth is related, which means we all must share a single common evolutionary ancestor. And now it appears that this ancestor might have been a single, planet-spanning organism that lived in a time that predates the development of survival of the fittest.
The Last Universal Common Ancestor is the great-grandparent of everything that has ever lived on Earth. Scientists had long assumed it was a crude, simple thing, more a chemical mishmash than anything else. But our earliest ancestor holds some surprises.
Lots of organisms rely on symbiotic relationships, in which two species rely on each other for survival and one lives inside the other. But citrus mealybugs enjoy a triply symbiotic relationship unlike any we've ever seen...with one absolutely crucial exception.