1. Kingdoms and Domains 18.3

2. Domain
• Most inclusive taxonomic category; larger
than a kingdom.

3. Bacteria
• Domain of unicellular prokaryotes that
have cell walls containing peptidoglycan.

4. Eubacteria
• Kingdom of unicellular prokaryotes
whose cell walls are made up of
peptidoglycan.

5. Archaea
• Domain of unicellular prokaryotes that
have cell walls that do not contain
peptidoglycan.

6. Archaebacteria
• Kingdom of unicellular prokaryotes
whose cell walls that do not contain
peptidoglycan.

7. Eukarya
• Domain of all organisms whose cells have
nuclei, including protists, plants, fungi,
and animals.

8. Protista
• Kingdom composed of eukaryotes that
are not classified as plants, animals, or
fungi.

9. Fungi
• Kingdom composed of heterotrophs;
many obtain energy and nutrients from
dead organic matter.

10. Plantae
• Kingdom of multicellular photosynthetic
autotrophs that have cell walls
containing cellulose.

11. Animalia
• Kingdom of multicellular eukaryotic
heterotrophs whose cells do not have
cell walls.

12. Key Concept
• What are the six kingdoms of life as
they are now identified?
–The six-kingdom system of
classification includes the kingdoms
Eubacteria, Archaebacteria, Protista,
Fungi, Plantae, and Animalia.

13. Key Concept
• What is the three-domain system of
classification?
–The three domains are the domain
Eukarya, Which is composed of
protists, fungi, plants, and animals; the
domain Bacteria, which corresponds to
the kingdom Eubacteria; and the
domain Archaea, which corresponds to
the kingdom Archaebacteria.