2. Kingdoms and Domains: Scientists debate how many
kingdoms there are.
The three-domain system
Bacteria Archaea Eukarya
The six-kingdom system
Bacteria Archaea Protista Plantae Fungi Animalia
The traditional five-kingdom system
Monera Protista Plantae Fungi Animalia
BioEd Online
3. Domains
There are 3 Domains
Bacteria- cells contain cell walls with
Peptidoglycan (polymer that has 2 kings
of sugar).
Archaea- cells contain cell walls without
Peptidoglycan.
Eukarya- contains Eukaryotic cells.
Contains the Kingdoms Protista, Fungi,
Plantae and Animalia
6. Kingdom Protista
Eukaryotic organisms that can be
unicellular or multicellular. Has no organs.
Ex: plant like protist = algae
Ex: animal like protist = protozoans
Ex: fungus like protist = molds & mildews
7. Kingdom Fungi
Unicellular or Multicellular Eukaryotes that
absorbs nutrients (heterotrophs).
Contains chitin
Ex: Mushrooms
10. DOMAIN Bacteria Archaea Eukarya
KINGDOM Eubacteria Archaebacteria Protista Fungi Plantae Animalia
CELL TYPE Prokaryote Prokaryote Eukaryote Eukaryote Eukaryote Eukaryote
Cell walls with Cell walls Cell walls of Cell walls of Cell walls of No cell walls or
CELL cellulose in chitin cellulose; chloroplasts
peptidoglycan without
STRUCTURES some; some chloroplasts
peptidoglycan
have
chloroplasts
NUMBER OF Most unicellular; Most Multicellular Multicellular
Unicellular Unicellular
CELLS some colonial; multicellular;
some some
multicellular unicellular
MODE OF Autotroph or Autotroph or Autotroph or Heterotroph Autotroph Heterotroph
NUTRITION heterotroph heterotroph heterotroph
Streptococcus, Methanogens, Amoeba, Mushrooms, Mosses, ferns, Sponges,
EXAMPLES Escherichia coli halophiles Paramecium, yeasts flowering worms,
slime molds, plants insects, fishes,
giant kelp mammals
Editor's Notes
Kingdoms and Domains In the 18 th Century, organisms were considered to belong to one of two kingdoms, Animalia or Plantae. As biologists gathered more information about the diverse forms of life on Earth, it became evident that the two-kingdom system did not accurately reflect relationships among different groups of organisms, and the number of kingdoms increased. In 1969, Robert Whittaker proposed a five-kingdom system consisting of monerans, protists, fungi, plants and animals. In the last few years, comparative studies of nucleotide sequences of genes coding for ribosomal RNA and other proteins have allowed biologists to recognize important distinctions between bacteria and archaebacteria. The graphic on this slide illustrates the phylogenetic relationships drawn from this information using a three-domain and a six-kingdom arrangement, compared to the traditional five kingdom system. References Woese, C. R. & Fox, G. E. (1977). Phylogenetic structure of the prokaryotic domain: the primary kingdoms. Proceedings of the National Academy of Sciences of the United States of America. 74(11), 5088-90.
