Researchers say multicellular life could have arisen in Earth’s oceans more than 2 billion years ago, only to fall victim to a drop in oxygen levels.
That scenario is based on a study of concentrations of the element selenium of sedimentary shale, led by researchers at the University of Washington. The findings – published online in the Proceedings of the National Academy of Sciences – shed light not only on the origins of life on Earth, but on the potential for detecting life on distant planets.
