Life on Earth is constantly shaped by our ever-changing planet. Mountain ranges and sea barriers cut species off from one another, causing new species to emerge or older ones to die out. Volcanoes give birth to islands that pioneering species later settle, becoming adapted to their newfound homes.

But this planetary-wide sculpting is a two-way street, as the National Geographic series One Strange Rock explores in its latest episode. Once life got its start billions of years ago, it got to work utterly transforming the way our planet's surface and atmosphere are structured.

More than two billion years ago, microbial life started harnessing the sun's power via photosynthesis, belching out oxygen in what's called the Great Oxygenation Event, a chemical