species vs subspecies

species

noun
  • A category in the classification of organisms, ranking below genus; a taxon at that rank. 

  • A group of plants or animals having similar appearance. 

  • A mineral with a unique chemical formula whose crystals belong to a unique crystallographic system. 

  • Either of the two elements of the Eucharist after they have been consecrated. 

  • Visible or perceptible presentation; appearance; something perceived. 

  • A component part of compound medicine; a simple. 

  • A particular type of atom, molecule, ion or other particle. 

  • Type or kind. (Compare race.) 

  • Coin, or coined silver, gold, or other metal, used as a circulating medium; specie. 

subspecies

noun
  • A rank in the classification of organisms, below species. 

  • A taxon at that rank, often indicated with trinomial nomenclature (such as Felis silvestris silvestris in zoology and Pinus nigra subsp. salzmannii in botany). 

  • A subdivision of a species in other scientific disciplines. 

How often have the words species and subspecies occurred in a corpus of books? (source: Google Ngram Viewer )