Taxonomy – the science of classifying organisms

Why do we need a system to classify and name organisms?
Here are some common names:

spider monkey	sea monkey	sea horse
gray wolf	firefly	crayfish
mud puppy	horned toad	ringworm
black bear	jellyfish	spiny anteater

These names can vary by region and can also be misleading. Is a sea horse really a horse?

Naming Organisms:

Organisms have common & scientific name -all organisms have only 1 scientific name
-usually Latin or Greek
-developed by Carolus Linnaeus

This two-word naming system is called…..

Binomial Nomenclature

-written in italics (or underlined)
-1st word is Capitalized –Genus
-2nd word is lowercase —species

Examples: Felis concolor, Ursus arctos, Homo sapiens, Panthera leo , Panthera tigris.   These can also be abbreviated as  (P. tigris or P. leo)

Linneaus also devised the system we use to organize animals.  This system uses large groups divided into subgroups (like the way you organize folders on your computer)

Kingdom —  Phylum — Class — Order — Family — Genus — Species

	Human	Lion	Tiger	Pintail Duck
Kingdom	Animalia	Animalia	Animalia	Animalia
Phylum/Division	Chordata	Chordata	Chordata	Chordata
Class	Mammalia	Mammalia	Mammalia	Aves
Order	Primate	Carnivora	Carnivora	Anseriformes
Family	Homindae	Felidae	Felidae	Anatidae
Genus	Homo	Panthera	Panthera	Anas
Species	sapiens	leo	tigris	acuta

Each organism has a group and subgroups. The organisms with the most similar groups will be most closely related.  Note that both the lion and the tiger are in the same genus, but are considered to be separate species.

There are currently 6 kingdoms – organisms are placed into the kingdoms based on the number and type of cells they have,  and their nutritional needs.

	number of Cells	energy	cell type	examples
archaebacteria	unicellular	some autotrophic, most chemotrophic	prokaryote	“extremophiles”
eubacteria	unicellular	autotrophic and heterotrophic	prokaryote	bacteria, E. coli
fungae	most multicellular	heterotrophic	eukaryote	mushrooms, yeast
plantae	multicellular	autotrophic	eukaryote	trees, grass
animalia	multicellular	heterotrophic	eukaryote	humans, insects, worms
protista	most unicellular	heterotrophic or autotrophic	eukaryote	ameba, paramecium, algae

Additional Links on Taxonomy

Build a Cladogram |  Tree of Life Web Project