Chapter 26 Phylogeny and the Tree of Life Overview: Investigating the Tree of Life Phylogeny is the evolutionary history of a species or group of related species. The discipline of systematics classifies organisms and determines their evolutionary relationships. Systematists use fossil, molecular, and genetic data to infer evolutionary relationships. Taxonomy is the ordered division and naming of organisms. Binomial Nomenclature In the 18th century, Carolus Linnaeus published a system of taxonomy based on resemblances. The two-part scientific name: Genus species. The first letter of the genus is capitalized, and the entire species name is italicized Both parts together name the species. This is the species specific epithet. Hierarchical Classification