 Principles of Systematics, module number one, first of all we will cover basic terminologies of Principles of Systematics, our first terminology is taxonomy, we can define that taxonomy as theory and practice of classification of organism, basically taxonomy two words first word is taxes which means arrangement and second word is greek word which means nomos or nomos arrangement or laws basically in taxonomy we arrange organisms into different groups and subgroups caroless lineus introduced the term taxonomy, it is also called father of modern taxonomy caroless lineus, swedish, botanist, zoologist and a maher position they divided organisms into different categories, according to them we can divide organisms into three categories similarly they introduced the system of binomial nomenclature and hierarchical classification in binomial nomenclature we give a name of two parts, first part represents its genus and second part represents its species caroless lineus said that we can divide all organisms into three categories and all organisms can easily be adjusted in these three categories among them the first category was animals, second category was plants and third category was minerals our second term is classification, classification is basically arrangement of organisms into groups and subgroups based on the similarities and differences they have basically in this we divide organisms into different groups and subgroups based on similarities and differences because of classification the study of organisms becomes very easy and convenient we can divide organisms into different groups on the basis of different factors for example we can divide organisms based on nuclear membrane for example nuclear material has a definite nuclear membrane absent whereas eukaryotic cells have a nuclear membrane, it is bounded by a definite nuclear membrane similarly we can divide organisms based on number of cells we can divide organisms based on number of cells similarly we can divide organisms into various groups on the basis of mode of nutrition many organisms are herbivores who feed on plant matter many are carnivores who eat meat similarly some organisms can consume plant and animal matter, we call them omnivores similarly many organisms feed on detritus matter, we call them detri-vores similarly we can divide the organisms on the basis of body organization many organisms have silo, which is a body cavity if all these characters are present in an organism we call them true silo and in such organisms we call them silo mate and in such organisms these silo don't exist, we call them as silo mate and some organisms have silo in them but if the characters are not complete then we call these organisms as pseudo silo mate or false silo mate and this total is called father of classification basically he made many groups, many categories for organisms he divided organisms on different basis on different groups for example he classified organisms based on the presence of blood or absence he divided organisms based on two footed or four footed similarly he classified organisms based on hairs or feathers similarly he classified organisms based on shell or shell absence but unfortunately he failed to give any consistent system of classification