Charles Darwin famously imagined evolution as a tree full of branches, a metaphor that biologists have since used to depict how life is structured. Now, researchers have given the tree of life another overhaul.
A team of scientists from the University of California, Berkeley, have been collecting the genomes of new microbial species over the last few years, and wanted to know how they fit on the existing tree of life. The old tree contained three mains “trunks”: eukaryotes (which includes animals, plants, fungi, protozoans, and us), bacteria, and collections of microbes that live in extreme environments.
The team from University of California, Berkeley took the genome data from 2,072 existing species along with 1,011 of their new species to work out where the newly discovered species fit in. They used a supercomputer to imagine different configurations of the tree and work out which made most sense, reports the New York Times.
Their findings reinforce findings made in earlier trees, which showed the whole of the eukaryote section—that’s the one in which we can find our own species—as a single, spindly branch. But the new tree shows that the branches made up of bacteria overshadow the eukaryotes more than ever, meaning there’s even more diversity in bacterial life than previously thought.
Many of the new species with such amazing diversity were found in rather mundane places, such as Californian meadows, while many are also incredibly simple creatures. But while that suggests we may yet see the tree grow further, scientists speaking to the Times seem to disagree about whether or not the tree of life is reaching its limits.