And by making our planet biologically singular, the Columbian Exchange completely remade the populations of animals, particularly humans. And vitally, this cross-pollination also made possible such wonders as contemporary pizza. So we're going to break Columbian Exchange down into four categories. Diseases, boy you're looking good, smallpox, I'm glad you've been eliminated. Animals, plants, and people. Mr. Green, Mr. Green, people are animals. Yeah, that's true, me, from the past, but just for the sake of simplicity we're- Also, if you think about it, microbes are kinda animals, and plants are too, I mean- Oh my god, shut up before I kill you and create a time travel paradox.