 So let's talk about the Archaeans. Remember, okay, first let me tell you this. If you had an Archaean and a bacterium and you set them both right next to each other and you looked at them, you would literally be like, that thing is a bacteria. That is, like, they're identical. And they're both prokaryotes. They both are... well, Archaeans aren't nearly as diverse or popular as bacteria. And however, they have the histone proteins that they share with eukaryotes. So where are you going to see some Archaeans? We actually see them living in crazy, extreme environments. For example, this is a picture of Yellowstone National Park. This is a hot springs, a boiling hot springs. Don't fall in that. And don't throw a rock for your dog. My dog fetches rocks. Most dogs would not fetch rocks, but my dog, my dog won't fetch a stick. But rocks, she'll totally go swim after rocks, but she doesn't get them because, you know, they sink. All right, anyway, don't throw a rock or a stick for your dog at this boiling mud pot hot springs in Yellowstone because it's boiling in there. But critters can live. Can most bacteria live in there? No, can you live in there? No, like cells pop living in boiling environments like this. The cell itself cannot survive. And yet Archaeans can. How do they do this? Not only do they live in boiling mud pot crazy heat, they live in crazy, salty concentration zones. Like they can live in the ocean. They can live in places where it's even saltier than the ocean, which means that they can withstand like some crazy pressures. They can live in super acidic environments or super basic environments. They can even live in frozen environments. They can just be fine. They're just doing their thing. They are structurally different and that's what enables them to do this. Some things that make them structurally different, their cell membranes are kind of more solid. Like, remember how we talked about cell membranes or like this, this, what was it called? Fluid matrix, fluid mosaic. Fluid mosaic where things just kind of float around and move around. Archaeans have a more solid cell membrane, which makes sense because it's going to be less likely to break apart if it is more solid. What else is there that you need to know? Oh, they can live without oxygen. Like they often are, they just live in extreme places. You might be like, okay, that's awesome, but who cares? And the fact is that we care, well, scientists care because if they have enzymes that can function at super high temperatures or super salty zones, our enzymes would stop working. But if their enzymes can keep working, we could actually harvest their enzymes and get their enzymes to do work for us in factories and not have to control the temperature. And I'm thinking about like mass producing something and having enzymes that can function in the high temperatures that result when you're like producing something. And I'm sure that I can't get any more specific than that, but I'm sure that in lecture we can come up with some examples of why heat is produced when you mass produce things. Now let's talk about eukaryotes. Now, so we're going to talk about single cell eukaryotes first, which are our group of protists.