Climate change potential trigger for complex life on earth

How did we get here? Understanding the evolution of complex life forms on Earth is probably one of our most fundamental questions. Scientists turn to the Cambrian explosion, a time roughly 542 million years ago, for answers.

Up to that point, Earth was home to simple, single-cell organisms. Then, suddenly, animals and plants made their appearance. To find out why that happened scientists look at fossils and other evidence that has since been set in stone.

One of these scientists is Mark McMenamin. The field paleontologist and geology professor at Mount Holyoke College in Massachusetts studies prehistoric life and its origins. He and his team discovered a Triassic giant amphipod in Nevada, believed to be the oldest of its kind and predating other amphipoda by at least 170 million years. He’s also examined the remains of a gigantic Triassic kraken in Nevada and filed the first-time report of an early Cambrian sponge in Mexico. Along the way, he wants to find out why these life forms came into existence.

McMenamin already has an idea. “Geochemical changes on earth are directly linked with evolution and biological transformation,” he says. This means that a change of climate may have inspired evolution to come up with new and more diverse forms of life to fit the new conditions. To prove his point, he looks at rock records of natural disasters like wildfires, floods or hurricanes as signs of ancient climate change.

McMenamin noticed a particular pattern of plant imprints in stone from the Mesozoic era in the Connecticut Valley region. He wasn’t sure whether he was dealing with the fossilized aftermath of a hurricane or a flood, so he reached out to peers on ResearchGate. His question caught the attention of researchers working across a range of disciplines, and numerous suggestions were put forward.

tornado rock

One geoscientist proposed looking for trees twisted in a spiral. A biologist suggested looking at the sedimentary structure in the area and its potential chaotic flow of direction. And an anthropologist said large fragments of shredded plant material would help uncover the mystery.

“By refining the image of ancient tornado activity, I hope to better understand the evolution of organisms living at that time,” Mcmenamin says. He picked up the twisted tree hypothesis that came up in the Q&A to confirm whether it really was a hurricane that edged the strange patterns in the rock. This insight may not only help understand how life diversified some 500 million years ago – but may also offer clues how climate change could act as a driver for evolution in the future.

Photo of a tornado in Oklahoma City, USA, courtesy of National Oceanic and Atmospheric Administration (NOAA) ; Rock photo courtesy of Mark McMenamin.