The Extinction of the Ediacarans

The Ediacarans dominated the oceans for tens of millions of years but died out when active animals appeared and dramatically disturbed their quiet and calm environment.

First complex creatures before animals came to a messy end.

Life in the Ediacaran Sea, display at the US National Museum of Natural History (Photo by Ryan Somma, cc-by-sa-2.0)
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The Ediacarans were the first large and complex life forms on our planet, and dominated the oceans for more than 40 million years.  These organisms are known today by rare and delicate fossils, but their biology is a great mystery to paleontologists. 

Part of the reason for that mystery is that the Ediacarans disappeared when the first large animals appeared about 540 million years ago, and left no descendants.  Dr. Marc Laflamme, a paleontologist from the University of Toronto at Mississauga, and his colleagues, think they now know what happened to the Ediacarans

By examining fossil sediments from Namibia that run through the period of the Ediacaran extinction, they think they've found signs of "ecosystem engineering" by the newly evolved, vigorous and active animals, who dug up ocean sediments, stirred up the water, and basically made the oceans uninhabitable for the sedentary and delicate Ediacarans.

Related Links

- Paper in Proceedings of the Royal Society B
- Vanderbilt University release