What is it about?

Major changes in diversity are recognized as significant events throughout the fossil record of animals. Here we compile a global database of the oldest animal communities, the Ediacara Biota, to investigate potential factors responsible for changes between faunal assemblages. We find an extinction of 80% of organisms around 550 million years ago. Our results demonstrate that this is not due to irregularities in the fossil record, and instead reflects true biotic turnover. The disappearance of a range of ecologies and preferential survivorship by animals who could likely withstand lower oxygen concentrations across this interval suggest that a global reduction of oxygen availability may have been responsible for this extinction.

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Why is it important?

Our findings show that, like all previously recognized major mass extinctions in the fossil record, the extinction of some of Earth's oldest animals was caused by environmental change.


This article was truly a group effort. In response to limited travel during 2020 and 2021, a group of graduate students at the University of California, Riverside compiled the comprehensive dataset of Ediacaran fossils used to conduct this work. It is a fantastic example of adapting to unusual circumstances to produce something of importance.

Scott Evans
Virginia Polytechnic Institute and State University

Read the Original

This page is a summary of: Environmental drivers of the first major animal extinction across the Ediacaran White Sea-Nama transition, Proceedings of the National Academy of Sciences, November 2022, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2207475119.
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