Over 600 million years ago, sheets of ice coated our planet on both land and sea. How did this happen? And most importantly for us, why did the planet eventually thaw again? The evidence for Snowball Earth is written on every continent today.

We all belong to the only group of hominins on the planet today. But we weren’t always alone. 100,000 years ago, Eurasia was home to other hominin species, some of which we know our ancestors met, and spent some quality time with.

As a scientific concept, evolution was revolutionary when it was first introduced. With the help of all three of our hosts and the Smithsonian National Museum of Natural History’s new Deep Time Hall, we’ll try to explain how evolution actually works and how we came to understand it.

Despite the name, we don’t know where the so-called “hell pigs” belong in the mammalian family tree. They walked on hooves, like pigs do, but had longer legs, almost like deer. They had hunched backs, a bit like rhinos or bison. But as is often, if not always, the case, there is some evolutionary method to this anatomical madness.

Throughout the Pleistocene Epoch, the range of the woolly rhino grew and shrank in sync with global climate. So what caused the climate — and the range of the woolly rhino — to cycle back and forth between such extremes?

All of today’s big cat species evolved less than 11 million years ago and yet their evolutionary history remains an almost total mystery. But scientists have recently discovered a major clue about the origins of the big cats, one that could provide a whole new starting place for solving this puzzle.

From our deepest origins in Africa all the way to the Americas, by looking at the fossils and archaeological materials we have been able to trace the path our ancestors took during thee short window of time when we took over the world.

The short-faced bears turned out to be remarkably adaptable, undergoing radical changes to meet the demands of two changing continents. And yet, for reasons we don’t quite understand, their adaptability wasn’t enough to keep them from going extinct.

The ability to make and use fire has fundamentally changed the arc of our evolution. The bodies we have today were, in many ways, shaped by that time when we first tamed fire.

Sea scorpions thrived for 200 million years, coming in a wide variety of shapes and sizes. Over time, they developed a number of adaptations–from crushing claws to flattened tails for swimming. And some of them adapted by getting so big that they still hold the record as the largest arthropods of all time.

The tools made by our human ancestors may not seem like much when you compare them to the screen you’re looking at right now but their creation represents a pivotal moment in the origin of technology and in the evolution of our lineage.