First animals developed complex ecosystems before the Cambrian explosion

The evolutionary stage for the Cambrian explosion was set when animals formed complex ecological communities more than 500 million years ago, according to a study by Rebecca Eden, Emily Mitchell, and colleagues at the University of Cambridge, UK.

Around 500 million years ago, the first animals evolved. The fossil record shows that after an initial boom, diversity declined in the run-up to the dramatic burgeoning of biodiversity. The drop in diversity is thought to be evidence of a mass extinction event that took place roughly 500 million years ago.

Researchers analyzed the meta community structure of three fossil assemblages that span the last 32 million years of this geological period to evaluate the evidence for an Ediacaran mass extinction. They used published paleoenvironmental data, such as ocean depth and rock characteristics, to look for metacommunity structure indicative of environmental specialization and interactions between species. The analysis showed that the community structure in the later fossils was becoming more complex, suggesting that species were becoming more specialized and engaging in more inter-species interactions towards the end of the Ediacaran era.

The authors say that the cause of the diversity drop in the late Ediacaran period was competitive exclusion. The features of ecological and evolutionary dynamics were established by the first animal communities in the late Ediacaran, according to the analysis.

Mitchell says that the factors behind the explosion, namely community complexity and niche adaptation, actually started earlier than previously thought. The Ediacaran was the source of the explosion.

More information: "Metacommunity analyses show an increase in ecological specialisation throughout the Ediacaran period" PLoS Biology (2022). DOI: 10.1371/journal.pbio.3001289 Journal information: PLoS Biology Citation: First animals developed complex ecosystems before the Cambrian explosion (2022, May 17) retrieved 17 May 2022 from https://phys.org/news/2022-05-animals-complex-ecosystems-cambrian-explosion.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.