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- Mar 16, 2016
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- The Desert
Tiny, tubular structures uncovered in ancient Canadian rocks could be remnants of some of the earliest life on Earth, scientists say.
The straw-shaped “microfossils,” narrower than the width of a human hair and invisible to the naked eye, are believed to come from ancient microbes, according to a new study in the journal Nature. Scientists debate the age of the specimens, but the authors' youngest estimate — 3.77 billion years — would make these fossils the oldest ever found.
Claims of ancient fossils are always contentious. Rocks as old as the ones in the new study rarely survive the weathering, erosion, subduction and deformation of our geologically active Earth. Any signs of life in the rocks that do survive are difficult to distinguish, let alone prove. Other researchers in the field expressed skepticism about whether the structures were really fossils, and whether the rocks that contain them are as old as the study authors say.
But the scientists behind the new finding believe their analysis should hold up to scrutiny. In addition to structures that look like fossil microbes, the rocks contain a cocktail of chemical compounds they say is almost certainly the result of biological processes.
If their results are confirmed, they will boost a belief that organisms arose very early in the history of Earth — and may find it just as easy to evolve on worlds beyond our own.
If these really were living bacteria at some point, and the dating process is mostly accurate, we might have to flip on its head what we thought of how life evolved when the Earth was only several hundreds of millions of years old. Specifically, many scientists believed that more complex life like bacteria (complex relatively speaking from the primordial soup theory) didn't evolve until later(2.5-2.9 bya) because of the tumultuous condition of early earth.
What is exciting too is the prospect that given the hypothetical that all of this is true, bacteria could/can survive in conditions harsher than we currently observe--leading some speculation that they may have done the same on other planets. It doesn't answer the grandaddy question of them all, "how did life first appear?" but gives us a reason to think that life is hardier than we think.