Join the Amoeba Sisters as they introduce the cardiac conduction system! This video mentions conductive cardiac cells (focusing on pacemaker cells) in the SA and AV nodes and discusses general steps of spontaneous depolarization. It also...

Join Pinky and Petunia in a cell types review game! This review game focuses on comparing cell characteristics of animals, plants, fungi, "protists," archaea, and bacteria. Clues may include prokaryote/eukaryote, autotroph/heterotroph,...

If DNA is just a string of letters, could AI learn to read it … or even write it? Bioengineering researcher Eric Nguyen reveals how AI has upended the rules of biology, potentially creating a future where disease is cured with...

While we think we know a lot about dinosaurs – like how they moved and what they ate – for a long time, we haven’t been able to ID one seemingly basic thing about their biology... Which are males and which are females?

How did ants take over the world? Well, it looks like they didn’t achieve world domination all by themselves. They may have just been riding the wave of a totally different evolutionary explosion.

Around 6,000 years ago, in the Sahel region of Africa, a lone female mosquito buzzed through the lush, green savannah. She couldn’t know it, but the planet itself was about to change in ways that would see her descendants evolve to live...

How and why the giraffe's neck emerged in the first place has been a mystery that generations of biologists have argued over – one that has made us reconsider our understanding of how evolution actually works over and over again.

We all know Charles Darwin's theory of evolution, right? Natural selection? But what about his lesser-know theory of evolution: sexual selection. Let’s talk about how animals like peacocks, whose eye-catching physical traits make them...

Life’s been around on Earth for at least 3.7 billion years. But for most of that time, it was incredibly boring — just simple little cells squirming around in water. It only got interesting in the last few hundred million years. And that...

Have you ever looked at a cloud and seen a face? Or the front of a car and seen a face? Or an electrical outlet and seen a face? You definitely have. We all see faces everywhere we look thanks to a fun quirk of the human brain called...

Imagine the scale of raindrops if you were the size of a small bird. Or mosquito. Flying through a drizzle should be deadly! Like flying through falling cars and boulders. And yet it’s not, because nature has given them a...

How did dinosaurs become birds—and what good is half a wing? Join Joe and a few brave chickens as they recreate a brilliant experiment that helps solve one of evolution’s greatest mysteries: the origin of feathered flight.

Across life on Earth, blood comes in red, blue, green, purple, even clear. But why? And what makes your blood different from mine? This video will teach you everything you need to know about the strange world of blood—what it does, why...

In this menstrual cycle video, explore the ovarian cycle and uterine cycle with the Amoeba Sisters! This video will walk through major events in phases of the ovarian cycle (follicular phase and luteal phase) and phases of the uterine...

Join the Amoeba Sisters as they introduce the basics about cladograms and phylogenetic trees. The Amoeba Sisters walk through the process of building a basic cladogram and mention vocabulary such as: shared ancestral character, shared...

Join the Amoeba Sisters as they introduce angiosperms (flowering plants) before exploring flower parts, pollination, and double fertilization in angiosperms! This video also talks about the importance of pollinators.

Join the Amoeba Sisters as they explore the action potential. This video discusses resting membrane potential before going into the phases of the action potential including vocabulary such as depolarization, repolarization, and...

A biologist’s natural habitat is anywhere questions about life are being asked—whether the subject is a nematode or a narwhal, a single cell, or a whole ecosystem. In this episode of Crash Course Biology, we’re flipping the microscope...

Science offers a way of discovering and understanding the world around us, driven by questions and tested with evidence. And it’s a twisty-turny team effort— you won’t find many lone geniuses out there, or straight lines from hypothesis...

Biology is the study of life—a four-letter word that connects you to 4 billion years worth of family tree. The word “life” can be tricky to define, but a shared set of characteristics helps biologists identify living things. In this...

You can dye your hair, you can get a tan, but the color of your eyes is pretty much set in stone - or is it? From weird diseases to temper flare-ups and even iris implants, here are just a few ways that your eye color might not be so...

Plants may not seem like they’re doing much, but if you look closer, you’ll find a whole world just lurking beyond the surface. We’re talking chemical defenses, highways, and even ways to change the weather. In this episode, we’ll learn...

Life on Earth has weathered boiling-hot oceans and volcanic-ash-darkened skies—but that’s nothing like the climate change we’re experiencing now. In this episode of Crash Course Biology, we’ll talk about the greenhouse effect, learn why...

If cells and organs never talked to each other, an animal would fall apart faster than a boy band after the popular one goes solo. Thankfully, that’s where the nervous and endocrine systems come in! In this episode of Crash Course...