Final answer:
Primates are called 'of the first rank' as part of Linnaeus's taxonomic classification because they are highly evolved creatures with complex adaptations. The hierarchal system includes various ranks from the broadest category of the domain to the specific level of species, facilitating clear communication in the scientific community.
Step-by-step explanation:
The term primate comes from the Latin for "of the first rank," which is reflective of the hierarchical taxonomic system developed by Carolus Linnaeus. Linnaeus used this term because he observed that primates, including humans, were highly sophisticated creatures with complex behaviors and traits—many of which were adaptations to arboreal life. In his Systema Naturae, he classified organisms into hierarchical levels: kingdom, class, order, genus, and species, with additional categories such as domain and family being added later on. This system facilitated a universal method for naming organisms called binomial nomenclature, which gives each species a unique, two-part name recognized worldwide, thus promoting clear scientific communication. The order Primates is divided into prosimians and anthropoids, reflecting a range of adaptations and evolutionary histories among its members.