CLASSIFICATION

Finding Order in Diversity

TAXONOMY•Discipline of classifying organisms

•Assigning each organism a universally accepted name

WHY CLASSIFY?

1. To name organisms 2. To group them in a logical

way

WHY CLASSIFY?

3. Classification makes life easier. What are some ways we classify?

CLASSIFICATION

• Organisms are put into groups that have biological significance

SCIENTIFIC NAMES

1. Using common names is confusing because many organisms may have several different common names.

2. The cougar is also known as the mountain lion, puma or catamount…thus the need for a scientific name.

Photo courtesy Texas Parks and Wildlife Department © 2004

Felis concolor

BINOMIAL NOMENCLATURE

• Developed by Carolus Linnaeus– Swedish botanist

• Two-word naming system – First name: Genus– Second name: species

BINOMIAL NOMENCLATURE

• First name: Genus– first letter is capitalized– italics or underlined

Ursus arctos

Grizzly bear picture is reproduced with permission from WWF. © 2004 WWF- World Wide Fund For Nature (Formerly World Wildlife Fund). All Rights Reserved. www.panda.org.

• Second name: species– first letter is lower-case – Italics or underlined

Ursus arctos

BINOMIAL NOMENCLATURE

LEVELS OF CLASSIFICATION

Domain KingdomPhylumClassOrderFamilyGenus

Species

LEVELS OF CLASSIFICATION

• Domain – largest and most inclusive

• Species – smallest and most specific

Three Domain System

KingdomsEubacteria

Archaebacteria

Protista

Plantae

Fungi

Animalia

DOMAIN EUKARYA

DOMAIN ARCHAEA

DOMAIN BACTERIA

CLASSIFICATION & RELATIONSHIPS

• The more taxonomic levels that two organisms share, the more closely related they are considered to be

What do the scientific names of the polar, grizzly and panda bears tell you about their similarity to each other?

Ursus maritimus

Ursus arctos

Ailuropoda melanoleuca

Pictures reproduced with permission from WWF. © 2004 WWF- World Wide Fund For Nature (Formerly World Wildlife Fund). All Rights Reserved. www.panda.org.

Organism

Cat Wolf Fly

Kingdom

Animalia Animalia Animalia

Phylum

Chordata Chordata Arthropoda

Class Mammalia Mammalia Insecta

Order Carnivora Carnivora Diptera

Family Felidae Canidae Muscidae

Genus Felis Canis Musca

Species

F. domesticus

C. lupus M. domestica

1. What type of animal is Musca domestica?

2. From the table, which two animals are most closely related?

3. At what classification level does the evolutionary relationship between cats and wolves diverge (become different)?

Animal; insect

Cat and Wolf

Family Level