The world's oldest `` almost all animal ancestors '' 550 million years ago are excavated
The oldest fossil, 550 million years old, has been discovered in the interior of South Australia. Fossils are crowded with small creatures like rice grains of 2 mm to 7 mm, and a research team who excavated fossils reports that it may be the world's oldest fossil of most animal ancestors including humans . .
Discovery of the oldest bilaterian from the Ediacaran of South Australia | PNAS
Fossil hunters find evidence of 555m-year-old human relative | Science | The Guardian
https://www.theguardian.com/science/2020/mar/23/fossil-ikaria-wariootia-bilateral-organism-human-relative
Creatures trapped in a fossil from 550 million years ago have been given the scientific name ' Ikaria wariootia ' after the indigenous people living in the area where they were discovered.
And when the research team checked the structure of the body of Ikaria wariootia, it turned out that the size of both ends was different. `` This may seem like a little thing, but Ikaria wariootia had a body that was distinguished back and forth, '' said Scott Evans, a member of the research team and a researcher at the Smithsonian National Museum of Natural History. I've shown it, 'he emphasized. The research team argues that 'Ikaria wariootia may be the oldest bilateral animal on earth, as it has been identified.'
The most primitive animal among multicellular animals is the
Bilateral animals are characterized by the fact that the embryo after fertilization is composed of three germ layers , and the body is clearly distinguished from the front and back, and is symmetrical. Many animals on the earth, such as dogs, birds, and insects, belong to this bilateral as well as humans. In other words, the oldest bilateral symmetric animal discovered this time can be said to be the ancestor of many animals on earth, including humans.
Previous studies had suggested that bilateral animals appeared in the Ediacaran era (approximately 620 million to 542 million years ago), but the fossils that support the theory are biological It is said that this is the first time that a fossil of the Ediacaran bilateral animal itself has been found.
In addition, the researchers analyze traces of holes through which organisms have passed, suggesting that Ikaria wariootia may have contracted muscles like an earthworm and moved through shallow marine sediments. The following image is an image of Ikaria wariootia.
'Ikaria wariootia appears to have emerged from the burrows for food and oxygen, indicating that Ikaria wariootia had acquired the ability to sense what was around him,' Evans said. And commented.
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