The Evolution of the Heart (A Love Story)

In order to understand where hearts came from, we have to go back to the earliest common ancestor of everything that has a heart. It took hundreds of millions of years, and countless different iterations of the same basic structure to lead to the heart that you have today.

Season 2 Episode 12 Length 09:00 Premiere: 02/14/19

Recent Episodes

The Fiery Rise of Flowering Plants

S8 E11 Length 10:45 Premiere Date 02/10/26

When Ancient Weeds Fooled Us

S8 E10 Length 11:37 Premiere Date 01/27/26

How Brawn Led to Brains

S8 E9 Length 12:14 Premiere Date 01/13/26

When a Tiny Land Bridge Triggered an Ice Age

S8 E8 Length 10:27 Premiere Date 12/17/25

What Was Greenland Like When it Was Green

S8 E7 Length 09:07 Premiere Date 12/02/25

How Chewing May Have Beat Extinction

S8 E6 Length 09:35 Premiere Date 11/18/25

Specials

When Dinosaurs Threw Up A Mystery

Length 09:15 Premiere Date 07/22/25

Did Dinosaurs' Extinction Give Us Fruit?

Length 10:47 Premiere Date 07/15/25

Why Paleontologists Can’t Stop Fighting About Spinosaurus

Length 08:37 Premiere Date 07/01/25

The Dinosaurs Too Big To Be Dinosaurs

Length 12:22 Premiere Date 06/17/25

Season 2 Episodes

Show Episodes

Show Clips & Previews

Were These Monsters Inspired by Fossils? (ASL)

S2 E59 Length 12:18 Premiere Date 10/29/19

When Giant Lemurs Ruled Madagascar (ASL)

S2 E58 Length 10:09 Premiere Date 09/25/19

When We Took Over the World

S2 E57 Length 11:47 Premiere Date 05/14/19

The Ghostly Origins of the Big Cats

S2 E56 Length 07:32 Premiere Date 05/31/19

When Penguins Went From The Sky To The Sea

S2 E55 Length 10:33 Premiere Date 03/26/20

When the Sahara Was Green

S2 E54 Length 07:50 Premiere Date 03/26/20

How a Hot Planet Created the World's Biggest Snake

S2 E53 Length 07:45 Premiere Date 03/09/20

When the Rainforests Collapsed

S2 E52 Length 07:40 Premiere Date 02/21/20

A Short Tale About Diplodocus' Long Neck

S2 E51 Length 09:18 Premiere Date 02/21/20

How South America Made the Marsupials

S2 E50 Length 09:51 Premiere Date 02/20/20

The Giant Dinosaur That Was Missing a Body

S2 E49 Length 12:00 Premiere Date 01/30/20

The Neanderthals That Taught Us About Humanity

S2 E48 Length 09:09 Premiere Date 01/23/20

That Time the Mediterranean Sea Disappeared

S2 E47 Length 11:10 Premiere Date 01/21/20

The Fuzzy Origins of the Giant Panda

S2 E46 Length 08:20 Premiere Date 12/19/19

The Forgotten Story of the Beardogs

S2 E45 Length 09:37 Premiere Date 12/19/19

Why Male Mammoths Lost the Game (w/ TierZoo!)

S2 E44 Length 11:02 Premiere Date 12/19/19

When Giant Hypercarnivores Prowled Africa

S2 E43 Length 09:17 Premiere Date 12/19/19

How We Domesticated Cats (Twice)

S2 E42 Length 07:47 Premiere Date 11/08/19

Were These Monsters Inspired by Fossils?

S2 E41 Length 12:18 Premiere Date 11/06/19

When Hobbits Were Real

S2 E40 Length 09:10 Premiere Date 11/06/19

The Case of the Dinosaur Egg Thief

S2 E39 Length 07:28 Premiere Date 11/06/19

When Antarctica Was Green

S2 E38 Length 11:03 Premiere Date 11/06/19

When Giant Lemurs Ruled Madagascar

S2 E37 Length 10:09 Premiere Date 11/06/19

How Pterosaurs Got Their Wings

S2 E36 Length 08:33 Premiere Date 11/06/19

When Bats Took Flight

S2 E35 Length 11:09 Premiere Date 10/24/19

The Raptor That Made Us Rethink Dinosaurs

S2 E34 Length 08:35 Premiere Date 10/24/19

The Missing Link That Wasn’t

S2 E33 Length 09:54 Premiere Date 10/24/19

Was This Dinosaur a Cannibal?

S2 E32 Length 10:37 Premiere Date 10/24/19

When Giant Deer Roamed Eurasia

S2 E31 Length 06:53 Premiere Date 08/13/19

How Earth's First, Unkillable Animals Saved the World

S2 E30 Length 10:12 Premiere Date 08/11/19

How Volcanoes Froze the Earth...Twice

S2 E29 Length 10:29 Premiere Date 08/11/19

When We Met Other Human Species

S2 E28 Length 12:56 Premiere Date 08/11/19

When Ichthyosaurs Led a Revolution in the Seas

S2 E27 Length 09:38 Premiere Date 06/25/19

When the Synapsids Struck Back

S2 E26 Length 10:10 Premiere Date 06/19/19

How Evolution Works (And How We Figured It Out)

S2 E25 Length 12:09 Premiere Date 06/13/19

The Hellacious Lives of the "Hell Pigs"

S2 E24 Length 07:17 Premiere Date 06/13/19

The History of Climate Cycles (and the Woolly Rhino)

S2 E23 Length 13:14 Premiere Date 06/03/19

The Croc That Ran on Hooves

S2 E22 Length 08:41 Premiere Date 05/01/19

The Mystery Behind the Biggest Bears of All Time

S2 E19 Length 10:41 Premiere Date 04/25/19

When We Tamed Fire

S2 E18 Length 11:46 Premiere Date 04/25/19

When Giant Scorpions Swarmed the Seas

S2 E17 Length 11:38 Premiere Date 04/04/19

When We First Made Tools

S2 E16 Length 09:08 Premiere Date 04/01/19

The Giant Bird That Got Lost in Time

S2 E15 Length 08:33 Premiere Date 03/12/19

The Island of Huge Hamsters and Giant Owls

S2 E14 Length 11:41 Premiere Date 03/12/19

How 7,000 Years of Epic Floods Changed the World

S2 E13 Length 09:28 Premiere Date 03/01/19