now we're going to talk about taxonomy and how we organize living organizations so we're going to go through different taxonomic levels that that going to have some pretty unfamiliar words to them um but it's just a like a file cabinet of living organisms at the broadest level we have what we call the domains and there's three domains to living organisms so you can see here down at the bottom here this is basically the origin of all living living organisms on earth this is the start of life after a short period of time life divided into two branches one of the branches became what we call bacteria so bacteria is the first domain these are all single celled they're prokaryotes so prokaryotes are just the bacteria that are unicellular they don't have a have a nucleus and they have a cell wall the other lineage that went on for a little bit and divided again one of those branches became the archaea these are also single-celled prokaryotes they have a cell wall that's made out of different materials and these are what we call extremophiles so they live in harsh environments stuff where there might be not oxygen or it's really hot or really salty or whatever it might be the other branching continued on became the eukaryotes this is what you typically think of when you think of life we are eukaryotes eukaryotes are single celled or multicellular organisms that have a nucleus some have cell walls as well like plants humans are a good example of these this so which one of these would not be a eukaryote we have a house sparrow here we have a tree we have an amoeba and we have bacteria here i believe e coli so this one would not be a eukaryote all three of these would be eukaryotes so now we're going to describe the taxonomic rankings so you can see down here at the bottom we have domain so this is where we're going to have the bacteria archaea or eukaryotes and then we have kingdom phylum class order family genus and species and we're going to use the domestic dog as an example so the domestic dog scientific name is canis lupus i'm going to break that word down down for you later but species is the only word the only taxonomic rank that'll have two words this is also the same scientific name as gray wolves because domestic dogs are artificially selected from gray wolves so in science when we want to refer to a domestic dog or grey wolf we use the term canis lupus now the first part of this word is the genus so canis cannas is a genus to a lot of the dogs that you're familiar with this includes coyotes so both coyotes and domestic dogs and gray wolves are in the genus canis if we take another step back to family now we're in all dogs so family canada includes all all canines all dogs this includes coyotes domestic dogs gray wolves foxes all dogs that you can think of we're going to step back in another bit to order and these are all the carnivora the mammals all mammalian carnivores roughly so this is like the tigers and the lions and that also all the canines we can then take another step back to class and now it's all mammals this includes rabbits and deers and the platypus and the echidna and whales everything in there we can then take another step back to phylum which is chordata so anything with a spinal forward so komodo dragons and snakes and lizards and fish and all the other stuff that we've already talked about and then kingdom so this is all animals not including the ones that don't have a spinal cord so spiders and ants and the cockroaches and everything else we've talked about as well and then what domain should these be in well these would be eukaryotes because we know they're not prokaryotes and they're not which means they're not bacteria or archaea so this will eukaryotes include all the plants all the fungi all the animals and also protists which is a group i'm going to talk about too much so another way to think about this is domain towards domain is the most inclusive includes the most organisms and up here is the most specific it has the most specific organisms you can kind of remember this in several ways so there's several mnemonics dear king philip came over for good soup so domain kingdom final class order family genus species do kangaroos prefer cake or frosting generally speaking you can go with your own mnemonics as well another way to look at this is do what's called a phylogeny which is like a tree that describes how living things are related so we described we went through how they're related based on their taxonomy we can look at that in a different way so we have domestic dog canis lupus is very closely related to coyotes so we branch them like that with canis you include foxes and you got the group candidate so coyotes are more closely related to foxes because this branch length is less and then there's second most related to foxes the candidate now what's important to realize though is in order to determine how related something is said to something else you can add up the branch lengths so calculate the distance here and here and here you can see how related they are so if you calculated the branch links from foxes to coyotes and then again from foxes to domestic dogs you get the same branch links and so foxes are equally related to coyotes and domestic dogs then you have carnivora mammalia chordata animalia and eukaryotes so this is just the taxonomic taxonomy portrayed in a phylogeny and we'll deal with phylogenes a lot more what do you think squirrels would be on this phylogeny so we know squirrels aren't carnivores and we know that they're mammals so we'd probably place a like squirrel branching off from right here where would mountain lions be so mountain lions are mammals they're also why we're going to be in carnivora so and we know they're cats so we have that line is branching off right here now another important piece to know is how to write out a scientific name so we already the scientific name is the scientific name for a species so we have canis uh lupus that we just talked about for domestic dogs we're gonna use the example of a tyrannosaurus rex here that everybody's familiar with that one so scientific name the species name always consists of two words the genus and the specific epithet now there's some rules here the genus is always capitalized the specific epithet is never capitalized when you write these out they're always italicized and you can refer to the genus by itself so if i was to say just tyrannosaurus i'm referring to all species in the genus tyrannosaurus or say the genus canis i'd be referring to domestic dogs gray wolves coyotes all of those combined now you can never have the specific epithet by itself so i can't just say rex that doesn't that doesn't uh specify anything so this physical prophet never stands alone um so you can write it if you write it like this tyrannosaurus you're saying there's a species of transfers i'm referring to i'm not quite sure which one if you write it like this just tyrannosaurus then i'm referring to all tyrannosaurs so go and perform this little task here make sure you're familiar with it so find a scientific name write out that scientific name find one species that is the same in the in the same genes as you described and identify the genius and specific epithet in the species name for each so that would give you a little practice working through this this process we're going to just use scientific names a lot in this class you should make sure you're very familiar with how to write these out and how to and what these mean if you have any questions please reach out