From Asgard to Earth: Tiny tubes may reveal the moment complex life began

Stromatolites—and their close relatives, microbial mats—could be mistaken for what seems like a bunch of old dark rocks. But instead, they are dense, layered communities of microbes. Long before complex life such as animals or plants existed, stromatolites breathed the first molecules of oxygen into Earth's atmosphere. Now, in a study published in Current Biology, researchers say they may also hold insights into how complex life began.