The document discusses the history of taxonomy and several early influential taxonomists: 1) One of the earliest was Caesalpino in the 1500s who classified 1500 species based on growth habit, fruit, and seed form. 2) The Bauhin brothers in the 1600s published a work listing 6000 species and helped establish genera and species as major taxonomic levels. 3) John Ray in the 1600s established species as the ultimate taxonomic unit and published a work with 18,000 plant species based on multiple characters.