It is not certain when or by whomandwere first technically distinguished asgenusandspecies. The distinction does not appear in Plato's extant writings, whereas Aristotle seems to take it for granted in theTopics, which is usually regarded as among his earliest treatises. In his dialogues Plato seems able to useinterchangeably to denote any group or division in a diairesis, including the group that is to be divided.

Dans la biologie d'Aristote, on voit volontiers, après Balme, une biologie sans espèces, la reproduction apparaissant alors comme une transmission de ressemblances individuelles. La prise en compte des diverses références à la ressemblance dans la théorie de la génération, montre cependant que pour Aristote, il existe des types; s'il y a plus d'une façon de garantir la perpétuation de ceuxci, la place des ressemblances individuelles est en tous cas mineure. It is now often thought with Balme that Aristotle's zoology is (...) a zoology without species, in which reproduction is but the transmission of individual resemblances. If one takes into account all the references to individual, sexual and specific resemblances in the theory of generation, one can see that, according to Aristotle, types exist; there is more than one way of perpetuating a type, but individual resemblances always remain a question of minor interest. (shrink)

It is not certain when or by whom S0009838800011642_inline1 and S0009838800011642_inline2 were first technically distinguished as genus and species. The distinction does not appear in Plato's extant writings, whereas Aristotle seems to take it for granted in the Topics, which is usually regarded as among his earliest treatises. In his dialogues Plato seems able to use S0009838800011642_inline3 interchangeably to denote any group or division in a diairesis, including the group that is to be divided.