The dominant theory on the origin of life is that life began in hydrothermal vents deep on the bottom of the ocean. Now, there's evidence that life may have begun in hot springs on land.
Earlier this year, scientists found 3.77 billion-year-old bacteria fossils, which turned out to be the oldest evidence of life on Earth. It supported the theory that life emerged from the oceans.
The oldest evidence of life on land is younger than the aforementioned bacteria fossils. However, there are new findings that suggest that microbes were present on land and in the ocean at roughly the same time. The big question now is which sparked life first—hot springs or hydrothermal vents in the oceans?
In a 1871 letter to his friend, the botanist Joseph Hooker, Charles Darwin postulated that life began “in some warm little pond with all sorts of ammonia & phosphoric salts — light, heat, electricity etc present”. Mr. Darwin may have been on to something.
A team of scientists found fossils of microorganisms in 3.5 billion-year-old rocks in a volcano in the Dresser Formation. The Dresser Formation lies in the Pilbara region in western Australia. The area had contained hot springs when the microorganisms were alive.
Researchers found bubbles in the rock that are evidence of the existence of ancient microbial substances. The fossils also contained stromatolites, which are layers of rock formed by layers of microorganisms. The rocks that contain the fossils are geyserite, which only occur around volcanic freshwater hot springs.
Tara Djokic, one of the study's authors, believes that it's more plausible that the origin of life is a hot spring instead of an oceanic hydrothermal vent. According to Djokic, the ingredients of life can occur in higher concentrations in hot springs. Hot spring waters circulate and thus can bring more minerals into the mix. These factors, especially the rich mixture of minerals, make it more likely that life began in terrestrial hot springs.
Still, these new findings don't mean that we should rule out the theory that the origin of life occurred in hydrothermal vents. However, the theory that life began on land now has more weight.
While we can't be completely sure yet where exactly life on Earth began, the findings can help with the search for life on another planet. Scientists have been hunting for evidence of life on Mars for years, but have so far come up with nothing. Of course, scientists haven't stopped looking.
The formation of both Mars and Earth occurred at around the same time. These fossil findings can help scientists look for signs of life on Mars in the right places, thus saving time, effort, and resources. There's already evidence that Mars also had hot springs as old as ancient hot springs on Earth.
Thus, these findings can pinpoint the origin of life not only on Earth, but also on Mars. Of course, previous theories on how life on Earth came about still hold weight. However, with this new evidence, we may need to rethink some things.
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