by Roberto — Sys­tem­atic clas­si­fi­ca­tion of or­gan­isms is a fun­da­men­tal part of bi­ol­ogy. Yet, de­spite its be­ing es­sen­tial, the species con­cept has a prob­lem; there is still no uni­ver­sally ac­cepted de­f­i­n­i­tion.