Researchers have analyzed the phylogenies of 448,112 bacterial lineages to better understand the global diversification dynamics of bacteria. The study provides estimates of speciation and extinction rates, and also estimates that there are up to 1.9 million extant bacterial lineages on Earth. The results indicate that bacterial diversity has been increasing over the past 1 billion years, and that current extinction rates are slightly below estimated speciation rates. In addition, the majority of bacterial lineages that have inhabited Earth over time are now estimated to be extinct, which is in contradiction to previous theories that bacteria are unlikely to go extinct.

The study provides important insight into the evolutionary history of bacteria, which are difficult to study in the fossil record of Earth.

The study, “Bacterial diversification through geological time,” was published in the journal Nature Ecology & Evolution. The work was supported by NASA Astrobiology through the Exobiology Program.