What water, chemistry and temperature cycles fostered the chemical reactions that allowed life to emerge on our planet? Because life arose in the largely unknown surface conditions of Earth’s early ...

In this feature, explore the history of life on Earth as we know it today, from the earliest bacteria to the first modern humans. Flash is a plug-in that allows for increased interactivity.

LUCA, the root of the evolutionary tree from which Bacteria and Archaea diverged, represents a key node in life’s history ... from Bristol’s School of Earth Sciences noted that LUCA’s ...

But as experts on the entangled history ... 10 billion years—and the time Earth took to produce humans—5 billion years, rounding up. He imagined three possibilities. In one, intelligent life ...

But the origins of life on our ... it from the Earth's atmosphere and then sent home. Michelle Thompson is an associate professor of Earth Atmospheric and Planetary Sciences at Purdue University.