An early start to the Earth’s biosphere
DOI: 10.1063/PT.5.023591
Nature : The Cambrian period, roughly 500 million years ago, was marked by a seeming explosion of diverse multicellular organisms. For the past 10–15 years, the carbon-isotope signature in Precambrian limestone has been studied for clues to what prompted this burst of life.Wild fluctuations in carbon-isotope values during the late Precambrian were interpreted as sudden, drastic changes in the global carbon cycle, such as methane releases or glaciations that could have altered ocean conditions to such extremes that an evolutionary burst was plausible. But new analysis suggests that photosynthetic organisms spread over land earlier than previously thought, and the subsequent rise in atmospheric oxygen was what triggered the Cambrian explosion
Related Link The late Precambrian greening of the Earth .
