Roughly 540 million years ago, something happened to fuel the explosive growth of complex, multi-cellular life, all over the planet, according to recent research.
Researchers led by Arizona State University (ASU) geologist L Paul Knauth found that such a profusion of life had been triggered by a massive greening by non-vascular plants.
Knauth and co-author Martin Kennedy, University of California, presented an alternative view of published data on thousands of analyses of carbon isotopes found in limestone that formed in the Neoproterozoic period, prior to the Cambrian explosion.
"An explosive and previously unrecognized greening of the Earth occurred toward the end of the Precambrian and was an important trigger for the Cambrian explosion of life," said Knauth.
"During this period, the Earth became extensively occupied by photo-synthesizing organisms," he added.
"The greening was a key element in transforming the Precambrian world - which featured low oxygen levels and simple, bacteria dominant life forms - into the kind of world we have today with abundant oxygen and higher forms of plant and animal life."
These findings appeared in the online version of Nature.