Phylum Arthropoda
Ticks are Arthropods, which are living creatures that have a hard exoskeleton, jointed legs and no backbone. Crustaceans such as crabs, lobsters and shrimp are also arthropods.
Class Arachnida
Creatures in the Arachnida class have two body parts, eight legs and no antennae. Scorpions, spiders, ticks and mites are part of this family.
Subclass Acari
The subclass Acari includes spiders and mites as well as ticks. Acari go through three distinct nymphal stages as they mature.
Suborder Parasitiformes
Parasitiformes include many varieties of parasitic species, the most famous of which are ticks and mites.
Ixodidae and Argasidae
Dr. Larisa Vredsoe, at the University of California--Davis, divides ticks into two categories. Hard ticks, called Ixodidae, have a hard outer shell. Soft ticks, from the Argasidae family, have soft bodies.