Welcome to Quantum Magazine's podcast. Each episode we bring you stories about developments in science and mathematics. I'm Susan Vallett.

Evolution is usually depicted as a consequence of the never-ending war between living things. The physical

environment around those living things plays

a part, but it's secondary to the intimate relationships that organisms have with one another.

These relationships are known to be the driving force of evolution, but it turns out that might

be just a recent development.

We hear about the ecological relationships as the primary force of evolution all the time,

from talking about symbiosis to the ongoing competitions between species called Red Queen's races.

But it wasn't always that way.

For example, in the oceans, ecological success was closely tied to the inanimate forces

steering ocean chemistry until only about 170 million years ago.

Complex organisms had been evolving since at least the beginning of the Cambrian period.

Killian Eikencier is a doctoral candidate at the University of Plymouth.

That's, what, 300 million years of evolution in the paedioshoic,

and all the time they were still, well, so susceptible to these

very basic geochemical shifts. Well, yeah, I find it surprising. I can see her, his advisor

Uveh Baltazar, and their colleagues showed something else in a paper last summer in nature

geoscience. They showed certain tiny marine creatures that emerged in the Jurassic

changed evolution in the ocean. About 250 million years ago, at the end of the Permian period,

life on Earth suffered an unprecedented blow. Something, perhaps massive volcanic activity in what are now the Siberian traps,

devastated the global ecosystem. It eliminated 90% or more of all marine species and upward of 70% of those on land.

The nearly cleaned slate marked the dawn of the Mesozoic era. Life was slow to recover.

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