pro Kerasiotes bacteria and archaea make up 60% of Earth's biomass. And by that I mean, if you took all the living organisms of Earth and you put them on a scale right, 60% of the weight that you'd be reading on that scale would be due to pro carry Ah, tick cells, right. These little microscopic organisms, they were the first life forms, Uh, and they also happen to be the most prolific. They're everywhere. I mean, they're inside us there on our skin, there, inside other creatures. If you take a scoop of ocean water, you're going to get a ton of them in there. I mean, these guys air everywhere, and they're also crazy places to like deep sea hydrothermal events. Um, they're just amazing organisms. And the reason I'm saying all of this is because it is, in a sense, tragic. How little we really get to talk about them in introductory biology. Okay, so we're doing a quick review of them here, But by no means should you take that as an indication that these air unimportant or un interesting organisms there actually some of the most important, most interesting life forms on the planet. Um, introductory biology just tends to be a little more focused on Thebes, up of organisms that, you know, humans interact or visibly interact with on a day to day basis. Okay, so take microbiology. It's truly fascinating. And now we're going to briefly, you know, almost criminally briefly discuss archaea, which are pro carry. It's similar to bacteria, but they have certain features that differentiate them from bacteria. And, of course, you carry outs. So they're of a similar size and shape to bacteria. But unlike bacteria they do not use, kept it a glide hand in their cell walls. The chemical composition of their membranes is distinct from both bacteria and eukaryotes. Now, just like bacteria, they have a circular loop of DNA, right? That's their chromosome. You'll find it in a nuclear oId in the cell. Uh, they also lack membrane bound organelles and a nucleus. Right? So they are, you know, pro carry its. They have all those defining pro carry attic features. However, uh, there are some interesting differences between them and bacteria. For one, their genetic machinery that they used for transcription and translation right gene expression happens to be more similar to you carry outs than bacteria, which is pretty fascinating. And it's also one of the reasons that you carry outs are thought you have evolved from Arcadia, not bacteria. And you might notice that in our little tree of life down here, right, here's our our route. Right. That's sort of the origin point. And we have a pro are sorry. Bacteria. Oops. Bacteria here. And, um, thes in red. Are you Kerasiotes? And then actually in green here, we've got our Arcadia, and you can see that, uh, the eukaryotes and the archaea have a common ancestor. So, um, additionally, archaea reproduce a sexually similar to bacteria, but like bacteria, they're capable of form of forms of gene transfer. And we're going to get into how that works in a different video. So take away is archaea are similar to bacteria, but there are some biochemical differences that separate them as a class of organism. Now, the thing most people tend to know about Arcadia is that they're extremophiles. But this is actually, um and anecdotal. I mean, certainly there are many species of extremophiles within Arcadia, but there are many, many, many types of Arcadia that don't live in extreme environments, right? So, really, the whole RK are extremophiles is not a good generalization. Um, now, looking at, uh, taking a look at this image here, these air some really famous archaea which you will find in Yellowstone. This is what's known as the Grand prismatic pool. It is a a sulfur rich hot spring, and the archaea that live in there are known as thermal files, right? They like heat. And, uh, you know, they will live in these hot springs, which are, I don't know, close to boiling point roughly. Um, they can also be found in these deep sea hydrothermal events that exude incredibly, uh, hot, hot, hot temperatures. I mean, you know, uh, way beyond boiling point. Right? So, you know, they don't all just like the most extreme temperatures. They like a range of temperatures. And that's really the point I'm trying to impress in general. Is that archaic? Could be found in all different types of environments. Um, some cool ones that I happen to like are the hail of files. And these like to live in salty environments. Um, including environments as salty as the dead sea. Right. Just in has such a high salinity level that, you know, if you were to swim in it, you feel the difference in density of the water. You know, it just feels very thick. Uh, now, Bethany Jen's are a really cool type of Arcadia. They produce methane as a byproduct of their metabolism, and these air found all over the place, they live in swamps, right? That's that kind of funky gross smell that you smell in swamps is, um, from methane in part and that stupid myth antigens. And also they live in the guts of animals and cows, for example. Are ruminants have thes Muthanna genes that live inside them? And that's, um, where the methane that they fart comes from. Now, the last thing I want to point out is, you know, main theme of biology, structure, fits, function. Right. So, uh, here we have the normal sort of fost Philip ID. Um, phosphate lipid, bi layer. Right. This is composed of what you can kind of think of a generic or vanilla Foss. Philip, it's right. And this you'll find in, you know, just regular old pro Kerasiotes eukaryotes. Whatever. Here, On the other hand, we have are, um, fossil lipids from the hot spring bacteria, and you'll notice that the actual chemical structure of these is pretty different. Right? And it's made of these ice a cream units. That's what, uh, thes air called Don't worry about the name. The main point is these false Philippines will stick together much more tightly, which is how the membranes of these hot spring pro Kerasiotes will resist breaking down at those high temperatures. So again, like structure, fits function and you're going to see these biochemical differences between theme the cells of Arcadia and he sells off bacteria. All right, that's all I have for this video. I'll see you guys later.
