A New Molecular Window on Early Life

In recent years, the boundary between the Archean and the Proterozoic--2500 million years ago--has been the boundary between a relatively well-studied biology preserved in fossils and a shadowland for paleobiological evidence for life on Earth. Brocks et al . now extend the chemical evidence for biomolecules from the previous 1700 million years to 2700 million years, by identifying biomarkers characteristic for cyanobacteria and eukaryotes in Archean rocks from rocks from Western Australia. The results show that a key attribute of eukaryotic physiology had already evolved 2700 million years ago.