Notes for 2.2 B

Biologists use seven levels of classification.

Linnaeus named about 4000 species.

• All 4,000 organisms Linnaeus named were plants or animals.

• Today, scientists have named over a million species.

• Linnaeus used appearance to classify organisms.

Naming Species

• genus—a group of species that have similar characteristics

• binomial nomenclature—a two-word naming system developed by Linnaeus (genus, species)

• Chameleo graciis

Naming Species (cont’d.)

• binomial--two names• nomenclature—list of names

• Ursus arctos

Using Scientific Names

• The scientific name must include both the genus and species names in order to be clear.

• Rules to follow:– Genus names comes first; the first letter is

capitalized, and the entire name is in italics or underlined.

– Species name is also italicized but not capitalized.Rhodedendron maximum

Organisms can be classified into seven levels.

• Major Taxonomic Levels• Kingdom

• Phylum • Class

• Order • Family

• Genus • Species

• Note: There are many subdivisions of the seven main taxonomic levels, such as Subphylum, Subclass, Infraclass, and so on. You may see many of these other sublevel taxa listed in the taxonomic tree of an organism. See pages 54-55 for examples.

Cont’d.

• In order to remember the levels of classification, create a memory aid such as:

• King• Phillip• Called for an• Order of • Fried• Great• Swordfish.

Dichotomous keys and field guides help people identify organisms.

• dichotomous key—a series of paired statements, each with only 2 answers, that can be used to identify an organism’s genus and species

• will give you the scientific name• See page 57B for an example.

Field Guides

• Field guides include paintings or photographs, maps, and other information .

• See page 58 B for an example.