Fossil Record Reveals Ancient Predator-Prey Interactions

Understanding how the historical basis was set for the current biodiversity is an important part of understanding our own origins as a species. Thanks to a new study, we now have a better grasp of the things that shaped our planet's species, their interactions, and their chances for survival.

The research focused on the Hangenberg extinction event which took place some 360 million years ago, at the end of the Devonian Period. The latter spanned between 416 and 359 million years ago.

The extinction event mostly affected the world's oceans, killing off most fish species, and leaving behind mainly the distant ancestors of sea lilies and starfish. In all fairness, this event is what facilitated the emergence of Tetrapods.

These are animals from which all dinosaurs and mammals eventually evolved. Our species, Homo sapiens, is also a direct descendant of these early ancestors. Until now, experts have had a hard time understanding how it was possible for this shift to occur at the end of the Devonian Period.

“This is the first time that specific, long-term predator-prey interactions have been seen in the fossil record. It tells us a lot about the recovery from mass extinctions, especially mass extinctions that involved a loss of predators,” says expert Lauren Sallan.

She holds an appointment as a graduate student at the Univeristy of Chicago Department of Organismal Biology and Anatomy. The scientist was also the lead author of a new paper detailing the findings, which is published in the esteemed journal Proceedings of the National Academy of Sciences (PNAS).

What the new research demonstrated was the long-term effects that extinction events have on ecosystems. The reasons why crinoids (sea lilies, starfish, etc.) managed to endure after the Hangenberg extinction event is because their predators were wiped out.

“This study demonstrates a clear example of processes that operate in ecological time – predator-prey relationships – becoming significant in evolutionary time,” says William Ausich, PhD.

“This means that ecological patterns and processes taking place today may have very long-reaching evolutionary effects. And although that idea may not seem particularly surprising at first, respected evolutionary biologists have long argued that it was not possible,” he adds.

Ausich is a professor of Earth Sciences at the Ohio State University (OSU), and also a coauthor of the PNAS paper. He explains that such studies could reveal in more depth how ecosystems react to major changes such as those brought on by extinction events, Daily Galaxy reports.