Appendix A

Appendix A: Major Divisions of Life

I. Definition of Taxonomy

Taxonomy – the branch of biology concerned with identifying, naming and classifying species of organisms. Taxonomy takes large groups of organisms and divides them up into smaller and smaller groups.

II. The Classification Categories of Taxonomy

The following are the classification categories of taxonomy. These categories move from general to specific and are discussed on page 308 of the textbook. To help you understand how taxonomy works, the common domestic cat is provided as an example of how an organism fits into these categories.

A. Divisions of Taxonomy

A useful mnemonic for remembering the divisions is: Dashing King Phillip can order fresh green salad.

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

B. Classification of the domestic cat Notice how each division becomes more specific.

Kingdom	Animalia	all animals.
Phylum	Chordata	all animals with backbones.
Class	Mammalia	all animals with backbones that are also mammals.
Order	Carnivora	all animals with backbones that are mammals and eat meat.
Family	Felidae	all animals with backbones that are mammals, eat meat and are cats.
Genus	Felis	a division of the Family Felidae that includes most of the small cats. Most of the large cats are in a different Genus (the Genus Panthera).
Species	catus	the domestic cat, a specific type of small cat in the Genus, Felis.

C. More Categories

It is important to remember that each one of the categories described above has several categories within that division. For example, there are over twenty different Phyla in the Kingdom Animalia. Chordata (animals with backbones) is one of these Phyla, the other Phyla classify all sorts of other animals (worms and bugs and the like). The following are some examples of major Phyla in the Kingdom Animalia. Within each of these Phyla, there would be several Classes.

1. Major Phyla of the Kingdom Animalia

Poriferans - the sponges	Cnidarians - jellyfishes and others
Platyhelminthes – flatworms	Nematodes - roundworms
Mollusks - clams, snails, and others	Annelids - segmented worms
Arthropods - crustaceans, arachnids, and insects	Chordates - fish, amphibians, reptiles, birds, and mammals

D. The Three Domains Taxonomy divides all life into three domains, listed below. Within the Domain Eukarya, it is important for you to know its 4 kingdoms. The eukaryotic kingdoms are also divided up into phyla, etc.. However, just some major phyla are included here. This is to reduce the need to learn the difficult names used for the various phyla.

1. Domain Archaea:

Archaeobacteria - primitive bacteria, live in extreme environments.

2. Domain Bacteria:

Eubacteria - the true bacteria

Cyanobacteria – Blue-green algae

3. Domain Eukarya

A. Kingdom - Protista: Single celled or colonial eukaryotes.

Protozoans - single celled eukaryotes

Algae - live in water, never form true roots like plants (even seaweed)

Slime Molds - live in moist places

B. Kingdom - Fungi: The different types of fungus.

Yeasts

Molds (bread mold etc…)

Mushrooms

C. Kingdom - Plantae: The plants.

Nonvascular plants - have no cells that transport water throughout the plant (mosses, etc…).

Vascular plants - do transport water between roots and leaves.

D. Kingdom-Animalia: The major phyla are listed above.

Appendix A: Major Divisions of Life

Last changed: January 21, 2007