Fossils suggest organisms diversified sooner than expected


From microscopic bacteria to beautiful flowering trees, insect colonies and huge whales, life is abundant on our planet. There are millions of different species in every corner of our world. When did the barren rock that was the Earth become a hive so rich in organic activity? New research suggests that the diversity of life we ​​see today may have started much earlier than previously thought.

The Earth is about 4.6 billion years old. Its beginnings were unstable: strewn with asteroids and experiencing extreme atmospheric and geological changes. Once things were settled, the “primordial soup” of chemicals left behind saw the beginnings of life with the appearance of the first single-celled organisms. New fossil discoveries suggest that these organisms began branching into different species much earlier than expected – possibly as early as 300 million years after Earth was formed.

Although that seems like a long time (and, don’t get me wrong, it is), it’s a relatively short time in geological terms and that surprises many scientists.

Learn About Early Life on Earth: Rethinking the Origins of Complex Life

A study published in Scientists progress looked at a rock from Quebec, Canada, estimated to be between 3.75 and 4.28 billion years old. The fist-sized rock contains microscopic filaments, knobs and tubes postulated in a previous Nature article believed to have been made by bacteria, predating the previously accepted first signs of ancient life by 300 million years. But some scientists weren’t convinced these structures were biological.

the Scientists progress The article presents new findings arising from further analysis. There is a description of a larger and more complex structure – a stem with parallel branches measuring almost a centimeter. While the researchers admit that some of the other shapes may not be biological, they argue that the “tree-shaped” branching fossil is most likely biological, as there are no known purely chemical reactions that could have created it. .

The authors also explain how the microorganisms could have obtained their energy. The chemical byproducts imply that ancient microbes lived on iron, sulfur and possibly also carbon dioxide and a form of photosynthesis without oxygen.

Lead author Dr Dominic Papineau of University College London said: “Using many different lines of evidence, our study strongly suggests that a number of different types of bacteria existed on Earth a long time ago. between 3.75 and 4.28 billion years ago.”

“That means life could have started as soon as 300 million years after Earth was formed. In geological terms, that’s fast – about one lap of the Sun around the galaxy,” he added. .

Another tantalizing aspect of the research is what it might mean about the possibility of life in other parts of the universe.

“These findings have implications for the possibility of extraterrestrial life. If life is relatively quick to emerge, given the right conditions, it increases the chances that life exists on other planets,” Papineau said.

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