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Paleontologists from the University of Oxford (UK), and Harvard and Yale universities in the United States revealed the secret of the appearance of the first multicellular animals (Metazoa) on Earth. According to the findings of scientists that living organisms originated about 800 million years ago. This was reported in an article published in the journal Interface Focus is the Royal society of London.
A molecular clock show that the first animals there were about 833-650 million years ago, although the oldest animal fossils date from just 580 million years ago. This discrepancy is explained by the fact that the environment was not always suitable for the formation of fossils (this process is called fossilization) and their conservation. However, in the new work, scientists have found that suitable fossilization conditions existed before.
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The researchers studied fossils of several geological formations: landscae group in Siberia the age of one billion years, as well as deposits of sedimentary rocks Svanbergfjellet (Spitsbergen) and Bennett (Arctic Canada), formed 800 million years ago. From the deposits of cut thin plate, which contained microfossils are fossilized traces of organisms. Using the focused ion beam, scientists have managed to produce vertical slices of fossil creatures and their immediate environment.
Infrared Microspectroscopy samples showed that the fossils are surrounded by kaolinite — minerals rich in aluminum. It is known that kaolinite that inhibit the growth of bacteria and slowing down the destruction of fossils has played a leading role in the formation of the Burgess shale (Cambrian period, 508 million years ago) in the Rocky mountains. In the shales of the Burgess paleontologists still find a huge variety of ancient organisms of the Cambrian period, including arthropods, worms, sponges and other multicellular creatures, which are difficult to classify.
In samples from Siberia, Spitsbergen and Arctic Canada was completely absent traces of Metazoa, although the studied sediments were formed under the same conditions as the Burgess shale. Based on this, the researchers came to the conclusion that the multicellular animals before 800 million years ago did not exist. Before that the planet was inhabited by bacteria, archaea, single-celled eukaryotes, green algae and other primitive organisms.
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