Classification – Arrangement
of plants or animals into groups based on their characteristics. There are many
ways plants and animals can be classified, e.g., as land or sea forms, day or
night, useful or nuisance, etc. While these classifications are often used to
organize popular books, scientific classification or taxonomy attempts to
classify animals based on their actual relationships with each other. This is
done by intimate studies of anatomy and physiology (such studies revealed that
sea turtles belong with snakes and lizards, while porpoises and whales belong
with the mammals, and neither is a fish...as both were once loosely classed);
by study of the fossil record; and, in recent years, DNA tests. Classification
details change from time to time as new evidence emerges and as scientists
change their minds over where to draw lines between groups: this is called the "lumpers versus
splitters" debate, and it never really ends. NOTE: The classification
categories given below are the basic ones. When additional levels of
classification are needed, prefixes "super," "sub," etc.,
are used to create new levels between these basic ones.
Kingdom – A very large
classification of living things, such as the plant kingdom or animal kingdom.
Phylum – A large
group of related plants or animals, usually with one major feature in common,
such as the Phylum Chordata (the creatures with a notochord, including all the
vertebrates
Class – A
subdivision of a phylum embodying creatures that share at least one trait in
addition to the phylum-defining one(s). Within the phylum Chordata are the
classes of major concern to zoo people: amphibians, reptiles, birds and
mammals. Examples of the traits that define a class would be the feathers on
birds and the milk that mammal mothers feed to their young.
Order – A
subdivision of a class embodying creatures that share at least one trait in
addition to the class-defining one(s). Within the mammal class, for example,
there are orders for the bats, the carnivores, the rodents and others. Examples
of the order-defining traits would be the wings of bats and the special teeth
of carnivores and rodents.
Family – A
subdivision of an order embodying creatures that share at least one trait in
addition to the class-defining one(s). Within the carnivore order, for example,
there is a dog family, a cat family, a bear family and a weasel family. A
defining traits of a family might be the short muzzle and retractible claws
possessed by most cats.
Genus – A group,
usually small, of closely related species. The first name in a two-word species
name is actually the name of the genus the species belongs to, e.g., the
domestic dog named "Canis familiaris" belongs to the genus
"Canis."
Species
–
A specific kind of animal whose members can breed with each other and have
normal babies together.