Dinosaurs Quickly Dominated Earth After Mass Extinction

Kristin Hugo

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Extinction events are critical to the history of life on Earth. Although everyone knows about the one that killed the dinosaurs, a mass extinction was also integral to creating a world where dinosaurs reigned—and we now know their takeover was fast.

Researchers at the University of Bristol in England used a mathematical model of animal life to confirm just how quickly the dinosaurs and their kin came to dominate Earth following the extinction event known as the Carnian Pluvial Episode. The dinosaurs took over in 2 million years—an extremely short time in the history of Earth—according to their study published in the Journal of the Geological Society.

Using a new statistical method called "breakpoint analysis" to evaluate fossil data, the researchers determined that the Carnian event occured about 232 million years ago. At that time, volcanic eruptions spewed chemicals in the air, dramatically altering Earth's climate. The resulting intermittent wet and dry periods were unfavorable to succulents, and conifers and other hardy plants took over. This change in the global ecosystem brough diversity of life to a sharp decline.

Soon after, 230 million years ago, the oldest known dinosaur evolved, and the reptiles came to dominate the skies, seas and land.

Mass extinctions "are usually easy to identify because of the sudden extinctions, followed by a gap, and then the recovery of life," according to a University of Bristol press release. The Carnian event, however, "was less easy to identify because the different sites around the world were hard to date and cross-match."

The Carnian event led to the spread of the dinosaurs across Earth, but it also eventually made way for species including crocodiles, turtles, lizards and even mammals, according to the release.

The researchers said hope their new approach can be used to pinpoint other mass extinction events in Earth's history.

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