This is a cup of yaupon tea. It is the only caffeinated drink that is native to North America. It is not closely related to this, which is a cup of black tea, much less this, which is a cup of coffee. Or this, which has guano. Or this, which is yerba maté. And none of those are related to this, which is chocolate. 

But all of those things have caffeine. 

Now, you might be thinking, "No, Hank. Chocolate has theobromine." 

And yes, that is chocolate's main stimulant, but chocolate always has a little bit of caffeine and sometimes, quite a bit of it. 

Tea, coffee, kola, cacao, guarana, yaupon, yerba maté - none of these plants shares a common ancestor that created caffeine. They all developed it a hundred percent on their own, in totally different parts of the world, which seems very weird, but it actually isn't the weird part. 

Actually, if you know enough, the fact that these all make caffeine isn't weird at all.  There is something weird - it's the thing that we always look past - but first, we have to talk about caffeine, which looks like this.

You might often see it tattooed on someone's forearm. But one thing you should see tattooed on more forearms is this, which is adenosine triphosphate or ATP. 

You think your energy comes from caffeine? Well, wait until you hear about ATP. But we're not gonna talk about the various ways that the body stores energy. No, instead, over here, you're going to notice a little group of atoms that looks not terribly unlike caffeine.
That little bit, if you break it off ATP, is called adenine.

And it is a very important molecule. You might recognize it as one of the four nitrogenous bases of both DNA and RNA. 

Once life had adenine to work with - and it had it pretty much the whole time - it did a lot with it. All living things, including plants, have enzymes that do a bunch of chemistry on adenine, turning it into hormones, waste products and energy storage.  Messing with adenine is one of the main things that life does. So, it's not surprising that occasionally, a plant might start making a bit of this adenine-derived molecule called caffeine - probably because some other adenine-related synthesis wasn't going quite right, but it resulted in a new thing. And oftentimes, when a plant creates this unnecessary accidental byproduct, that plant will be more likely to survive and reproduce than nearby plants because caffeine is a bug poison. 

Now, it's also a people poison. If you eat four or five grams of it, you will die. But it's more potent of a poison for bugs. Part of that's just dose: a bug has to eat a lot of leaves to get the nutrients it needs to survive, and it's going to eat a lot of caffeine along the way and it's going to get super-dosed with this molecule. 

The wild thing is that caffeine does the same things in our bodies that it does in bug bodies. It just does it more dangerously in bugs because they get a higher dose and also, bugs are worse at processing the molecule. It does, like, three different things to bugs, and it does all three of those things to us. 

So, the most important thing that it does in us, the biggest biochemical effect it has on us is mimicking the neurotransmitter, adenosine, which you might guess, also adenine-derived. But with all the different activity that it has inside of bugs, it makes them seize up and jitter and shuts down their nervous systems and then they die.

It can also, by the way, poison plants. And you're never gonna guess how it does that. By mimicking adenosine! It does the same thing in plants! 

There's also some plant-specific effects, but basically, if a plant evolves to be able to contain a bunch of caffeine, which is toxic to the plant, but it also evolves immunity along with evolving the caffeine so that it can keep the bugs off of it. 

An additional thing that will happen is that it will poison the soil around it for any plant that isn't immune to caffeine, and that can be another advantage for the plant that makes caffeine. So basically, pretty much any time a plant evolves a mutation that causes it to churn out a little bit of caffeine, that plant gets eaten less.  And because it's so similar to a bunch of other molecules that plants are already making, caffeine is easy to evolve and provides a large survival advantage. So, it has evolved many times - probably way more times than we know about. 

Maybe the best fact I learned about, researching this video, is some plants even evolve the ability to put a little bit of caffeine in their nectar, so that bees will, instead of dying, get high off of the nectar and be more likely to return to that flower. 

What? What? What? I love that! 

Now, there's also some closely related molecules like theophylline, which there is a little bit of in tea and theobromine, which is the big one in chocolate, and they act basically the exact same way. They are also insecticides, though not as potent as caffeine, and they have very similar effects on a person's body, though again, not as potent as caffeine. 

Because, again, the reason it kills bugs and the reason it evolved is also the reason we like it. It's messing with our physiology, but just enough that it gives us that little extra pep and is also a little bit addictive without being so addictive that it ruins your life.  

The weirdest thing about all of this isn't that each of these plants independently evolved caffeine; it's that humans independently evolved drinking teas made from each one of these caffeinated plants. And yes, coffee is technically a tea.  Also, the Olmecs originally ate cacao as a tea. Though, probably, it was so wildly and intricately spiced that you wouldn't recognize it as a tea; definitely, a drink, though. 

These are groups of humans separated by oceans and millennia, and they're all drinking caffeine. This is amazing! We love caffeine! We love it so much. The practice of drinking caffeine teas has arisen seven different times. Tea in China in East Asia, coffee in the Horn of Africa and Arabia, cacao in Meso-America, kola nut in West Africa, guarana in the Amazon basin, yerba maté in the southern coast of South America and yaupon in south-eastern North America. 

But John, there is an eighth way! An eighth way that we get caffeine now, which is what's in here. What plant do you think the caffeine in sodas comes from? Guess? Do you have it in you? 

That's right. The chemical plant. 

Did I shake it too much? I did. 

Now, we could and sometimes do use the caffeine left over from decaf coffee. But that comes with a bunch of flavor from the coffee and is actually more expensive. So mostly, beverages are caffeinated with caffeine made entirely by humans. We make it from scratch now. We're like, "Plants, I don't need you. I don't need you." 

Mmm, derived from petroleum. 

God, I don't love that drink, John. I'm sorry. 

Now, by far, my favorite way of getting caffeine is tea, green tea or black, which are actually from the same plant - just prepared differently. I like tea because there's less caffeine per drink, which is great for me. There's also more theophylline, which produces a milder vibe. 

I'm sweaty. Geez. What.. am I on drugs right now? 

There is some interesting research that an amino acid called L-theanine, that is in tea, can kind of combine with the caffeine to give you a more chill vibe while keeping you aware. But to get real deep into that, I feel like I need to make a whole video about it. Regardless, my mornings are little bit more delightful with a cup of tea than with a cup of coffee. Just for me. I think that's part of why it remains the most popular drink in the entire world.

John, after I first wrote this video, which is a while ago now, I realized I needed to do a thing. I decided to put together an experience, because that's one of my favorite things about teas: the experience. And so, the experience I have created is a six-month subscription to Keats and Co. Loose-Leaf Tea. 

Each month, you get a different tea, and you also get a little video from me where I talk about how I'm going to try to calm down for a second. 

Okay. Let's take it again. 

Every month, you get a different tea, and you also get a little video from me where I talk about how I prepare my tea and have a cup while I  chat with the camera. The teas are gonna swap back and forth between caffeinated and herbal, and I've designed it to, sort of, start simply and then build from there. It's called Hank's Tea Experience , and the quantity is limited; shipping is free, and all the profit goes to help in the fight against tuberculosis, which may be the only thing more ubiquitous in the human story than caffeine. 

John, I'll see you on Tuesday.