More than half a billion years ago, life on Earth wasn't very interesting. No cats, dog, people, dinosaurs -- not even plants.
What did the landscape look like back then? Endless miles of green "pioneer vegetation," say according to researchers at Arizona State University and the University of California, Riverside.
The scientists think they've found the answer to what triggered an explosion of more complex, multi-cellular life that led to the plants and animals we know today. Before that explosion could occur, the researchers wrote in the science journal, Nature, these primitive, photosynthesizing life-forms covered the planet, dumping vast amounts of oxygen into the atmosphere.
ASU geologist L. Paul Knauth led the research, says Science Daily:
It was a massive greening of the planet by non-vascular plants, or primitive ground huggers, as Knauth calls them. This period, 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.
In other words, if it wasn't for this early green movement, we wouldn't have the Sierra Club or Toyota Priuses.