New Research Suggests: 'Cascade of Events' Caused Explosion of Life

The Big Bang. The Cambrian Explosion. The Quest for Fire.

The universe isn't short on fireworks, and it's easy - when thinking back on the prehistoric past - to imagine a single match lighting those fuses. Only now, researchers suggest that in the event of the Cambrian Explosion, there was no single cause.

"The Cambrian Explosion is one of the most important events in the history of life on our planet, establishing animals as the most visible part of the planet's marine ecosystems," lead researcher David Harper from Durham University said in a press release. "It would be naïve to think that any one cause ignited this phenomenal explosion of animal life. Rather, a chain reaction involving a number of biological and geological drivers kicked into gear, escalating the planet's diversity during a relatively short interval of deep time."

The Cambrian explosion, which occurred around 542 million years ago, was an evolutionary turn in the history of animal life on Earth. Prior to it, most life forms were single-celled organisms. After it, more complex species such as crustaceans, sponges, and mollusks helped lay the foundation for life as we know it today.

For Harper and co-researcher Paul Smith of Oxford University, the conclusion that the explosion wasn't created by a single cause but rather by a "cascade of events" does come with a caveat; they believe the antecedent cause to be the rising of sea levels and the subsequent expansion of the ocean floor.

From the explosion, all of the major groups of animals that we recognize today came to be; specialization of activity (such as burrowing and swimming) first appeared, and modern ecosystems built on complex biodiversity were established.

Said Smith: "This is a period of time that has attracted a lot of attention because it is when animals appear very abruptly in the fossil record, and in great diversity...

Because it is such a major biological event, it has attracted much opinion and speculation about its cause."

Apparently, he means "causes."