Phylum Arthropoda (870,000+ species)

• Class Crustacea (40,000 species) -- shrimp, lobsters, copepods, barnacles
• Class Chelicerata (63,000 species) -- horseshoe crabs, spiders, scorpions, daddy long legs
• Class Chilopoda (3,000 species) -- centipedes
• Class Diplopoda (10,000 species) -- millipedes
• Class Insecta (750,000+) -- butterflies, cockroaches, ants, etc.

• Class Polyplacophora (550 species) -- chitons
• Class Gastropoda (75,000 species) -- snails, slugs
• Class Bivalvia (2,000 species) -- clams, oysters, scallops
• Class Cephalopoda (660 species) -- squids, octopi, chambered Nautilus

Phylum Chordata (~43,000 species)

• Subphylum Urochordata (2,000 species) -- sea squirts
• Subphylum Cephalochordata (25 species) -- amphioxus
• Subphylum Vertebrata (~41,200 species)
  • Class Agnatha (65 species) -- lampreys, hagfish
  • Class Chondrichthyes (800 species) -- sharks, skates, rays
  • Class Osteichthyes (18,000 species) -- bony fish
  • Class Amphibia (3,100 species) -- frogs, salamanders
  • Class Reptilia (6,000 species) -- snakes, lizards, turtles
  • Class Aves (9,000 species) -- birds
  • Class Mammalia (4,200 species) -- mammals