hi everyone and welcome to learn a little biology for free with mr. stroke in this video is going to cover classification taxonomy binomial and phylogenetic or phylogeny classification so we'll begin with the binomial system and this is the way that you can name organisms and it's a universal method so regardless of the country language all scientists will follow the binomial system and this is where a organism is named and the first part is their genus and the second part the name is the species so by Gnomeo by means to know meal means name so there's two parts to the name and we've got some examples down here we've got the new zealand robin which is the common name that we use in english and then we've got it by known your name at the bottom so the Patrika is the genus Australis is the species robin so we can see here we've got the Arista 'kiss is the genus part of the name and the radicular is the species now the way that this is conventionally presented is it would always be in italics the genus gets a capital the species does not so the advantage of this is it gives you a much much better idea of how closely related organisms are because if we just use this common name which we've used in the English language it's very misleading we've got the New Zealand Robin and we've got just a Robin here and you might think from those names that they're very closely related but they're not actually and we can see that from the binomial name they're not the same species they're not even the same genus so they are not very closely related so that's the advantage of the biome your system number one it's universal so everyone will use the same system but also it's a way for you to see how closely related different species are to see are they in the same genus so another example we've got hair is we've got a tiger and a Jaguar and this time we can see that's the name the common name gave no indication as to the fact that they are closely related but they are actually closely related so although there are different species they're both in the Panthera genus so that then gives you information that these two species are closely related so why do some species look similar even though there are different species and we've got here the example of a camel and a llama so they've got lots of similar physical observable features and the reason for this links back to natural selection and evolution so they both live in similar environment so they might have similar climatic conditions they're thought they're going to be exposed to similar selection pressures and that then leads us through the stages of natural selection so that means similar alleles within their gene pools will have the selective advantage those will then give that individual an advantage to survival that we produce and pass on that annual so you'll find that the same or very similar alleles will become common in those two different species populations and because the Aniel is coming for a protein that means that making similar proteins and therefore similar characteristics so classification systems then and this links to what we were looking at with the binomial naming system one way to classify is using this hierarchy system and you do need to know what a hierarchy means in terms of classification and it's always a to mark question on an APA paper and it's always these exact two answers so number one small groups arranged within large groups number two there's no overlap between the groups so what does that actually mean having a look at this diagram we can see we have a hierarchy and we'll go through definition with the hierarchy so domain is the broadest way to classify organisms and that just classifies into three groups okay up prokaryotes eukaryotes then we have the kingdoms phylum class order family genus and species and we call each of these groups is called a different taxa so where it says a hierarchy small groups arranged within large groups if we look at species and genus so species are our smaller groups but within the same genus you can have lots of species so for example we looked at a tiger and a Jaguar two different species but they're both found within the same genus so that is our smaller groups arranged within a larger group so the small group of species but you have lots of different species within a genus and that's the same as you travel up our hierarchy now where it says there's no overlap between groups what we mean here is although there's lots of different species that are in the same genus there is no overlap in those species so a tiger is a completely different species to a Jaguar they cannot make fertile offspring together so that's what the definition it means now this exact classification system you do need to know off by hearts and the most common way this gets assessed is they will give you all of these taxa lined up in order but they'll miss some of them out and you have to fill in what are the missing taxa so they come up with a mnemonic just to help you to remember domain kingdom phylum class order family genus species so what is the point of going to all this effort to classify organisms in the first place well there are absolutely millions of species there's still lots are undiscovered as well so we need a way to organize them the reason for that is it helps us to understand relationships between organisms that helps us to track changes now whether that is tracking and understanding evolution or the impacts of climate change or the impacts that humans are having it can be a whole range of reasons and as I said we use the binomial system genus and species but also this classification system the Linnaeus system is universal so that means you can share data globally to help keep track of organisms so the way that organisms are then put into these different groups you have to be able to identify similarities and differences and originally this was just based on visible differences and similarities so it could be appearance behavior fossil records the downside with that is some members of the same species can look completely different so if you think about dogs for example dogs they're allowed to differ breeds that can look completely different but they're still all the same species or on the other hand you could have two different species which look very very similar so you might mistake two different species and think they're the same one so that's why it's no longer done just on appearance and we use much much more modern and accurate methods and these are your four methods that you need to know now the top three it explicitly says on a QA spec that you need to know looking at how similar the DNA base sequences or looking at how similar the mRNA basic base sequences or looking at how similar amino acid sequences are the more similar the sequence the more closely related the organisms are the fourth one is actually only on the spec where it says students should be able to also have an awareness of immunological comparisons as well and this is where you compare how closely related organisms are based on how similar their antigens are on their own cells and therefore any self antibodies they make they compare the shapes and the more similar the shape the more closely related they are so the last thing then is the phylogenetic classification so phylogeny or phylogenetic classification this is still the idea of grouping organisms according to some kind of similarity but this time it's specifically focusing on evolutionary origins and evolutionary relationships so this is a really useful classification system to be able to look at how closely related different species are but also where it says study in relationships what we mean by that is studying which species share common ancestors and what that means is a species that they evolved from and you can see that on phylogenetic trees so that's what we've got here through a whole range of different species including humans right at the top and every time there is a branch in this tree so what forks or splits into in this case two different species this point here represents the human and chimpanzee most recent common ancestor so that is the species that humans and chimpanzees evolved from so when you learn more about speciation the common ancestor is the original species but it diverged into humans and chimpanzees and then the further to the left we go is going further back in time and if we go all the way back we can see every single one of the species on this list here ultimately evolved from the same common ancestor it just would have been many many many many many generations ago we haven't got an indication of years here but it can't be as far back as millions of years that this common ancestor existed so that is it for classification I hope you found it helpful if so please give it a thumbs up and subscribe to you up-to-date [Music]