Ancient Mass Extinction Led to Dominance of Tiny Fish

According to new research led by Lauren Sallan, an assistant professor of earth and environmental science, a mass extinction 359 million years ago known as the Hangenberg event triggered a drastic and lasting transformation of Earth’s vertebrate community. Beforehand, large creatures were the norm, but for at least 40 million years following the die-off the oceans were dominated by markedly smaller fish.

“Rather than having this thriving ecosystem of large things, you may have one gigantic relict, but otherwise everything is the size of a sardine,” said Sallan.

The finding, published in Science, suggests that small, fast-reproducing fish possessed an evolutionary advantage over larger animals in the disturbed, post-extinction environment. It may have implications for trends we see in modern species today, such as in fish populations, many of which are crashing due to overfishing.

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To watch Sallan discuss her findings, click here.