Whether we’re talking about tigers, trees, or tarantulas, evolution happens at the level of the population. In this episode of Crash Course Biology, we’ll find out how natural selection, gene flow, genetic drift, and other processes...

Climate change shakes up all of Earth’s systems, including the living ones. In this episode of Crash Course Biology, we’ll see how climate change’s effects rattle the entire chain of life. Changes felt in one population ripple out to...

On its own, a huge DNA sequence is a meaningless pile of data — so, how do biologists figure out what it means? They turn to the power of bioinformatics! In this episode, we’ll learn what bioinformatics is, how it works, and how...

Your DNA contains all the instructions your body needs to function. In this episode of Crash Course Biology, we’ll figure out what this giant instruction manual looks like and how this three-billion-letter code gets copied into your...

Why do animals do what they do? It’s a huge question, and in this episode, we’ll learn how scientists break it down. We’ll talk about the proximate and ultimate studies they use to understand animal behavior, and some of what they’ve...

The cell membrane is a protein-studded phospholipid bilayer that not only protects our cells, but also regulates what goes in and out. In this episode of Crash Course Biology, we’ll look at the structure of the bilayer, learn about its...

This is a love letter to water, life’s solvent, and one of the most wonderful molecules around. In this episode of Crash Course Biology, we’ll learn about how water’s polarity and hydrogen bonding help it sustain life on a larger scale....

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...

Ecology is the study of the interactions of living things with each other and their environment. It’s a field that not only lets us explore the interconnections between living things, but also how our environment affects us, and how we...

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...

We've been talking about the unavoidables recently. Last time, we covered Death. This time, it's taxes. So, what are taxes? Why do we pay taxes? What is all that tax money used for? This week, Adriene is going to cover all that and more....

Profit, revenue, income, assets, cash flow -- all these words mean money, but they all have specific uses. In business, money is important to us and we want to describe it as accurately as possible.

In which John Green teaches you about World War I and how it got started. Crash Course doesn't usually talk much about dates, but the way that things unfolded in July and August of 1914 are kind of important to understanding the Great...

So we have Weather and Climate... but are they the same thing? No, no they are not. But they are both super important to how the geosphere is shaped. In this episode of Crash Course Kids, Sabrina chats with us about the differences...

So, what's the difference between 'weather' and 'severe weather'? Is it just how hard the wind is blowing? Is it just thunder and lighting? Well, it can be some or all of those things. In this episode of Crash Course Kids, Sabrina talks...

Sex is complicated for different reasons in different cultures. But, it's the entire purpose of life, so there's no reason to blush. In this episode of Crash Course Psychology, Hank talks about Kinsey, Masters and Johnson, Sexuality,...

In which John Green teaches you WHY World War I started. Or tries to anyway. With this kind of thing, it's kind of hard to assign blame to any one of the nations involved. Did the fault lie with Austria-Hungary? Germany? Russia? Julius...

At the end of World War II, the nations of Europe were a shambles. Today we'll learn about how the various countries and blocs approached the problem of rebuilding their infrastructure and helping their residents recover. You'll learn...

How much should you get paid for your job? Well, that depends on a lot of factors. Your skill set, the demand for the skills you have, and what other people are getting paid around you all factor in. In a lot of ways, labor markets work...

There are several ways the world could end, and scientists have given a lot of thought to what the last living thing will be.

As the 19th century gave way to the 20th, Black Americans were searching for ways to think about how and where they would fit into a post-slavery society. There were several competing schools of thought. Booker T. Washington and W.E.B....

So today Craig is going to look at political ideology in America. We're going to focus on liberals and conservatives and talk about the influencers of both of these viewpoints. Now, it's important to remember that political ideologies...

This week, Mike is teaching you about the most mythic of mythological creatures: Dragons. Cultures across the world (and across Westeros) tell stories of dragons, and their power to destroy, their power to prop up kings, and their power...

This week, Mike is teaching you about the most mythic of mythological creatures: Dragons. Cultures across the world (and across Westeros) tell stories of dragons, and their power to destroy, their power to prop up kings, and their power...