Experiments Show the Record of Early Life Could Be Full of 'False Positives'
Published:01 Feb.2021 Source:Geological Society of America
For most of Earth's history, life was limited to the microscopic realm, with bacteria occupying nearly every possible niche. Life is generally thought to have evolved in some of the most extreme environments, like hydrothermal vents deep in the ocean or hot springs that still simmer in Yellowstone. Much of what we know about the evolution of life comes from the rock record, which preserves rare fossils of bacteria from billions of years ago.
But that record is steeped in controversy, with each new discovery (rightfully) critiqued, questioned, and analyzed from every angle. Even then, uncertainty in whether a purported fossil is a trace of life can persist, and the field is plagued by "false positives" of early life. To understand evolution on our planet -- and to help find signs of life on others -- scientists have to be able to tell the difference.