You may have heard some pretty bold claims about xylitol, a sugar substitute that's in a lot of things. And while it's definitely bad for dogs, it's great for people, and there's a lot of research out there about some surprising ways...

Biology connects all of life—all of YOUR life. In the final episode of Crash Course Biology, Dr. Sammy is taking your questions. No matter how big, small, or personal, biology is in them all! He’ll show us how biology can help us solve...

Bacteria often get a bad rap, but they’re some of our best partners in science and medicine! In this episode, we’ll explore what bacteria are doing with their DNA — including how they can trade it around. We’ll learn about chromosomes...

Science fiction is full of superpowered mutants, but in reality, mutations are much more diverse and complex. Sometimes, they can change someone’s entire body, and other times, we don’t notice them at all! In this episode, we’ll unpack...

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...

It’s not nature versus nurture—it’s both! In this episode of Crash Course Biology, we’ll explore how complex interactions between genes and the environment shape all sorts of traits, from human skin color to honeybees’ “royal jelly.”

How do traits get passed down in our DNA? And what do genes have to do with cat fur? In this episode of Crash Course Biology, we’ll untangle the simplest patterns of inheritance, and reassure our redheaded friends—you’re not going anywhere.

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...

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...

The Milky Way is often described as measuring 100,000 light years across and containing the mass of a trillion Suns. But our home galaxy is actually far bigger, and might be much less massive. Astronomers aren't sure what the exact stats...

You might think that an animal either lays eggs or has live young. But these species prove it's a lot more complicated than that.

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....

At more than 2 meters long, Aegirocassis was not only the biggest radiodont ever, but it also may have been the biggest animal in the Early Ordovician. This bizarre marine giant may have only been possible, thanks to a major revolution...

While clubs are practically synonymous with ankylosaurs, we’ve only started to get to the bottom of how they worked and how this unusual anatomy developed in the first place.

Strange geologic landmarks in the Pacific Northwest are the lingering remains of a mystery that took nearly half a century to solve. These features turned out to be a result one of the most powerful and bizarre episodes in geologic...

Woolly mammoths, our favorite ice age proboscidean, disappeared from Europe and North America at the end of the last ice age, about 10,000 years ago. Today, we’ve teamed up with TierZoo to solve one of the mysteries about these...

For some reason, animals keep evolving into things that look like crabs, independently, over and over again. What is it about the crab’s form that makes it so evolutionarily successful that non-crabs are apparently jealous of it?

These odd rodents belong to a genus known as Ceratogaulus, but they’re more commonly called horned gophers, because, you guessed it, they had horns. And it turns out the horns probably had a purpose - one that rodents would likely...

It might surprise you but cephalopods have a pretty good fossil record, with one major exception. If squids were swimming around in the same oceans as their closest cousins, where did all the squids go?

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 the short window of time when we took over the world.

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.

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.