A 6 Kingdom System

There are six kingdoms recognized, separated (somewhat imperfectly) by form (morphology) and mode of nutrition: Classifications of this nature differ among biologists, this is not a cause for concern, but an indication of healthy debate.

Note that the basis for this classificatory scheme is cellular features, such as the presence or absence of membrane-bound organelles.

The Six Kingdoms are: (For more visual denotation scroll down)

1. Archaebacteria--Prokaryotic, unicellular, nutrition by absorption (heterotrophic). This group of bacteria-like organisms live in harsh (high temperature, salinity, etc.) environments similar to that of ancient earth (hence the name). They cell wall structure is different than that of typical bacteria. A recent study revealed that their genome is 44% unique from that of other prokaryotes or eukaryotes. They are, however, more closely related to the latter. Based on this enormous genetic difference (most closely related species are different by 0.5%) has lead many biologists to consider them a new kingdom, or higher domain.

2. Eubacteria--Prokaryotic, unicellular, nutrition mainly by absorption (heterotrophic) with some photo- or chemosynthesis (autotrophic) "all single celled organisms with no membrane surrounding the genetic material (Bacteria, Blue-green algae) and circular DNA. These organisms play a major role in global recycling, breaking down dead organisms to nutrients. Eubacteria often form mutualistic relationships (both benefit) with many other organisms including corals and humans. Many human diseases are caused by Eubacteria; bubonic plague, typhus, syphilis, gonorrhea, botulism, and most other forms of food poisoning.


All of the remaining 4 kingdoms are Eukaryotes (membrane surrounding the genetic material =nucleus) - DNA bonds with proteins to form chromosomes. The cells also have internal membrane system of organelles.

3. Protista--typically unicellular, eucaryotic, nutrition by absorption, ingestion and photosynthes. Most single celled organisms with membrane surrounding the genetic material (e.g. Amoebae). Multicellular forms do not form organs from tissues. Some of commercial value, algae produce thickening agents used in ice cream, tooth paste, floor polish, cosmetics, thick shakes, etc. Three major human diseases are causes by protistians, Malaria (Plasmodium); amoebic dysentery (Entamoeba); and African Sleeping Sickness and Chagas' disease (Trypanosoma). In the oceans, much of the plankton is protistian. Diatom and dinoflagellates are the base of most aquatic food webs and supply up to 90% of the atmospheric O2.

All of the remaining three kingdoms are multicellular eukaryotes that form organs from tissues but have different mechanisms to obtain their nutrition

4. Fungi-- multicellular, eucaryotic organisms, nutrition by absorption (heterotrophic), cell walls made of chitin digest externally and absorb nutrients, Also play a major role in global recycling. Break down dead organisms to nutrients. Food sources for humans. Some cheeses get their flavor from fungi. We also ingest their reproductive structures (mushrooms). Yeast is used to leaven bread and produce ethyl alcohol for making beer and wine. Some produce hallucinogens - perhaps leading to some of the darkest chapters in human history.

5. Plantae-- multicellular, eucaryotic, rigid cell walls, nutrition by photosynthesis (make their own nutrients converting solar energy into chemical energy in the bonds of sugar molecules; autotrophic). Plants are a major food source for many other organisms. Most of our plant foods come from Angiosperms, the flowering plants. All fruits (including nuts and grains) are flowering plant reproductive structures.

6. Animalia-- multicellular, eucaryotic, nutrition mainly by ingestion with internal digestive tract, ingest and internally digest their food. Most, but not all, groups display locomotion (animation, hence the name). We interact with this group in many intimate ways, from food to pets.


The Six Kingdoms

How are organism placed into their kingdoms?

       Cell type: Prokaryote or Eukaryote

       Their ability to make food: Autotroph or Heterotroph

       The number of cells in their body: Unicellular or Multicellular




       Autotrophs & Heterotrophs


Description: http://1.bp.blogspot.com/-g94lYbQmRqo/Txfv3ujK9dI/AAAAAAAAD-U/STaFDl-zgU8/s400/bact2.jpg

The bacteria you know

        The Good(probiotics, bacteria that make yogurt and cheese, decomposers, etc)

        The Bad (Staphylococcus, streptococcus, salmonella, etc.)

        And the Ugly

Description: http://t0.gstatic.com/images?q=tbn:ANd9GcQXNF_exET9CRMLtsl_Y-L-UFCfECdQ5emlK7c80zxy3Ma9_U0JDescription: http://t2.gstatic.com/images?q=tbn:ANd9GcTRkuH10ZrcqcemrKfSKoZbU2xpQinGJ0cSz_l1lWeB_4L3EMer6g



       Autotrophs & Heterotrophs


Bacteria found in extreme environments:  thermal vents, salt lakes, no oxygen environments, highly acidic environments.

They differ chemically from Eubacteria in their cell wall, cell membrane, tRNA, and DNA, and ribosomes.



       Autotrophs & Heterotrophs

       Unicellular & Multicellular

Description: http://t0.gstatic.com/images?q=tbn:ANd9GcSjuDC6dY7pHtRjKDOWFtw6H5Dl5OZR6ZG6dCL8BlUU4iOMVZwCxg  Description: http://t1.gstatic.com/images?q=tbn:ANd9GcTByrf5ZVUQ0pBLjlkcs4Wj1AYJDO4ALaBrY9eE1c9O7vOIDN6-_A 

Parmecium, Euglena, Amoeba, algae, kelp




       Multicellular (yeasts are the exception)

       Cell wall

Description: http://t2.gstatic.com/images?q=tbn:ANd9GcTcuuao5p9taZ6usS_mtbVHo5dyJ4OXTvzwpJhRYi1L_hRWn3MX 

Mushrooms, molds, yeast





       Cell wall

Description: http://t0.gstatic.com/images?q=tbn:ANd9GcRtNQ0dX9cuUqBZCdlikbyGUOmUfOKrPYPDAdEK9FuP2ltWs_oUdov5VLMo Description: http://t3.gstatic.com/images?q=tbn:ANd9GcQJQ4pgB9IInGgrqq6eL4uyvyx1fpC_H7Vi0OvB1UIm5sUp_rFwzw 

Mosses, coniferous trees, deciduous trees, flowering plants






Jellyfish, worms, snails, insects, fish, amphibians, reptiles, birds, and mammals



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