Fossil study finds how sea level changes shaped early life on Earth – ThePrint – ANIFeed

Edinburgh (UK), August 4 (ANI): A newly developed timeline of early animal fossils suggests a link between sea level fluctuations, variations in marine oxygen and the emergence of the earliest ancestors of today’s animals.

The first animals found at this time were all marine, at a time when oxygen levels in the air and ocean were much lower than they are today.

Although early life forms before this time were mostly simple single-celled and multicellular organisms, creatures of the Ediacaran Period began to become more complex, with multiple cells organized into body plans that allowed them to feed, reproduce, and move across the ocean floor.

This era also marked the emergence of so-called bilateral animals – which exhibit symmetrical body plans, in common with most living species, including humans.

By compiling data from different sources – including radioactive dating and geochemical information about the rock layers in which the fossils were found – the team mapped all the major fossil discoveries and various environmental datasets onto a single timeline.

The new chronology allowed the team to study biodiversity trends over the period in question in more detail than before.

They combined these insights with other chemical clues from the geological record, confirming a link between major changes in global sea levels, intervals when shallow marine environments gained more oxygen, and the emergence and diversification of the first groups of animals.

These dynamics set the stage for several significant explosions in biological diversity, known as the Avalon, White Sea, and Cambrian sets, each marking the arrival of new groups of animals and the decline of others.

By reconstructing environmental conditions in deep time, the study reveals new insights into the ancient forces and pressures that shaped early life on our planet.

The team also identified gaps in the fossil record, suggesting that current knowledge about early animals is skewed by the clusters of locations around the world where fossils have been found and studied.

Dr Fred Bowyer, from the University of Edinburgh’s School of Geosciences, said: “Constructing a timescale of early animal evolution using the rock record is a daunting task, only possible through international, interdisciplinary research. But an integrated global approach is crucial. It exposes biases in our records, while also revealing patterns in fossil appearances, sea-level cycles and ambient oxygen.”

Mariana Yilales Agelvis, a PhD student in the School of Geosciences who co-authored the study, said: “Knowing what drives biodiversity is a fundamental piece of knowledge in the puzzle of life. I feel very privileged to have built on decades of interdisciplinary global research and contributed to a better understanding of the role that sea level plays in early animal evolution.” (ANI)

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