Power up the WHAT IF time machine because today, you’re traveling back to witness the most radical changes ever known in Earth’s history. You’ll watch our planet give birth to strange new animals and see continents taking shape. We’re going to the time that defines our existence, the Paleozoic Era.

But if you traveled back to this ancient time, how would your body react to the new climate? What kind of creatures would you eat? And how hot would the planet get?

The Paleozoic era began 530 million years ago when the Earth woke up from an ice age. This era lasted for 289 million years, but you might not even last five minutes in this climate. But hey, if you are as resilient as the life in these waters, you just might stay alive. In these oceans, life has the perfect space to begin. And like all great things, it started small.


Good luck trying to find a meal. 543 million years ago, all life on Earth lived below a thick layer of mud on the seafloor. But don’t get out your lobster bib yet. The only things you’d find here are microbes. So chewy. Your menu won’t be getting any bigger for a few million years, until the Cambrian Explosion, the big event that would kick-start life on Earth.

The cyanobacteria would pump more oxygen into the atmosphere, making it easier for you to breathe. So take a deep breath and enjoy life on this doomed continent. Maybe you could make a stew out of the new shelled animals popping up in the oceans.


During the Ordovician period 485 million years ago, you would watch North America and Europe merge to become the supercontinent known as Gondwana. Grab your parka though, because as this landmass moves over the south pole, a massive ice age would spread across the globe.

Under the water, jawless fish would roam the sea, dominating the ocean. Algae and sponges would begin living on coral reefs. And back on land, the first plants would take root. But 80% of the life in shallow seas would die as sea levels plummet when the new ice age begins.


Starting about 444 million years ago, you would see the glaciers melt. This event would create a climate similar to what we have now. The ocean would be full of sea scorpions the size of dogs, so look out. These opportunistic predators may confuse you for dinner.


In the Devonian period, three continents blanketed the planet. 419 million years ago, much of Earth’s landmass remained underwater. You would need to live near the shoreline to harvest the resources you need to stay alive. Since trees would be covering the world for the first time, you could build shelter and even start a fire.

With the soil rich in nutrients, you could begin to farm plants. While you would rule the land as an apex predator, the ocean would belong to the early sharks. And they look hungry.


Travel back 358 million years, and you would see life near the equator would thrive while the rest of the world would experience deadly temperature changes. The first reptiles would start appearing. Look out for that Ophiacodon.

They can grow almost 3 m (10 ft) tall. Even dragonflies can have wingspans of 75 cm (2.5 ft). One of those could feed you for a while. But don’t settle in yet. There’s one more period to visit before this era comes to an end.


All the changes we saw have led to this event, the Permian period. About 299 million years ago, almost every landmass on Earth had merged into the supercontinent known as Pangea. This massive land stretched from pole to pole, with vast deserts in the center. The wild temperature changes would kill amphibians, but don’t worry.

You wouldn’t be alone here. The Eryops would tower over you, standing 2 m (10 ft) tall. This lizard-like creature devoured its prey whole. If you keep out of its way, you might enjoy the new oxygen levels thanks to more trees sprouting up everywhere.

But you would see a violent end to this period. Whether it’s meteors, exploding volcanoes or methane clouds, 96% of all life would Earth die out, the highest extinction rate ever known. If you made it through, get back in the time machine.

You made it through one of the most defining eras in the history of this floating rock. But what if your time machine broke down and you were stuck in the Devonian period?

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