What is the method of naming organisms by their genus and species called?

The method of naming organisms by their genus and species is called binomial nomenclature. This system was developed by Carl Linnaeus in the 18th century and is fundamental to the field of taxonomy. It provides a standardized way to name species, ensuring that each species has a unique and universally accepted name.

In binomial nomenclature, the name consists of two parts: the first part is the genus name, which is capitalized and identifies a group of species that are closely related; the second part is the species identifier, which is not capitalized. This two-part naming convention helps avoid confusion that can arise due to the common names of organisms, which can vary by region and language.

The other methods listed are related to biological classification but serve different purposes. Phylogenetic classification focuses on the evolutionary relationships between organisms rather than simply naming them. Taxonomic hierarchy refers to the ranking system used to categorize organisms into different levels, such as domain, kingdom, phylum, and so forth, rather than the specific naming of a species. Systematic categorization encompasses a broader range of classification methods and inclusion of evolutionary history but does not specifically denote the naming convention used for individual species.