The classification of life, starting with Aristotle's attempts. Botanist Carl Linneaus worked out a system in 1735 whose primary categories are still in use. From largest to smallest, here is how we fit them:

• Kingdom: Animalia (animals)
• Phylum: Chordata (with nerve chords)
• Subphylum: Vertebrata (and backbones)
• Superclass: Gnathostomata (and jaws for biting)
• Class: Mammalia (the young feed on mother's milk)
• Order: Primata (primates
• Suborder: Haplorrhini (dry-nosed)
• Family: Hominidae (erect, walking mammals)
• Genus: Homo (humans and their close relatives, all now extinct but us)
• Species: Homo sapiens (this two-name genus/species form is called binomial nomenclature)