Cambrian explosion explained

An article in the online version of Nature by ASU geoscience prof Paul Knauth and a colleague offers a new explanation for the cause of the Cambrian explosion. In "The Precambrian greening of Earth," they conclude that,

a massive greening of the planet by non-vascular plants, or primitive ground huggers, as Knauth calls them, roughly 700 million years ago virtually set the table for the later explosion of life through the development of early soil that sequestered carbon, led to the build up of oxygen and allowed higher life forms to evolve. [right, carbonate layers hold carbon isotope evidence of the late Precambrian greening of the Earth. These are located in the Old Dad Mountains in California. Credit, Paul Knauth, ASU]

[taken in part from an ASU news release posted on Eurekalert]