1. Chapter 9
The Classification
of Organisms

2. Why Classify?
To place organisms in some systematic order

3. Taxonomy
The science of classifying organisms into groups

4. To assign an organism to a particular group
Classify
To assign an organism to a particular group
Identify
To determine the group to which an organism belongs

5. The Classification
Hierarchy

6. Aristotle Based his groupings on appearance
Artificial classification system
His system was used for almost 2,000 years.

7. Carolus Linnaeus Designed a new classification system in the mid-1700s
His system was based on observable characteristics but was more developed and adaptable.

8. Today’s System of Classification
Start with the broadest group or classification and work down to the most specific category.

9. Kingdom
Phylum
Class
Order
Family
Genus
Species

10. Rules for the Hierarchy
Each group can be divided into several groups on the next level.
Each group has characteristics that all levels under the group possess.
Each level can be subdivided before reaching the next level.

11. Kingdom Archaebacteria
Kingdom Eubacteria
Kingdom Archaebacteria
Kingdom Protista
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia

12. The Kingdom Eubacteria
Prokaryotic cells
Cell walls contain peptidoglycans.
Most abundant organisms on the earth

13. The Kingdom Archaebacteria
Prokaryotic cells
Cell walls do not contain peptidoglycans.
“Extremophiles”

14. The Kingdom Protista Eukaryotic cells Unicellular or colonial
Protozoans and algae

15. The Kingdom Fungi Eukaryotic cells
Unicellular or colonial (lack tissues)
All are heterotrophic.
Examples: molds, yeasts, and mushrooms

16. The Kingdom Plantae Eukaryotic cells Multicellular with tissues
Most are autotrophic.
Examples: trees, ferns, flowers, grains

17. The Kingdom Animalia Eukaryotic cells Multicellular with tissues
All are heterotrophic.
Examples: worms, sponges, insects, vertebrates

18. Scientific Names Binomial nomenclature
“Two-name” naming system proposed by Linnaeus
System of naming organisms in which each organism is given a genus name and a species name

19. Scientific Names Binomial nomenclature
Gives organisms a “genus-species” name

20. Using Scientific Names
Example: Canis familiaris
“Canis” (Genus: capitalized)
“familiaris” (Species: not capitalized)
Both names are underlined or italicized.

21. Why Latin?
Dead language
Known by scholars
Highly descriptive

22. Species A population of organisms
Structurally similar but with a degree of variation
Can interbreed and produce fertile offspring