Kingdom Monera

Kingdom Monera contains all known organisms consisting of prokaryotic cells. In contrast, organisms in the other four kingdoms (Animalia, Plantae, Fungi, and Protista) are composed of eukaryotic cells. Some members of the Monera are unicellular organisms; others are simple colonies of undifferentiated cells. Depending on the organism, some colonies may be very simple, consisting of only two cells. Other monera may have colonies of four cells, and some may consist of a filament of cells like a string of beads.

Nutritionally, some members of the Kingdom Monera are autotrophic while others are heterotrophic. The most commonly encountered members of the Kingdom Monera are bacteria and cyanobacteria (formerly called blue-green algae). Cyanobacteria and some bacteria are photosynthetic autotrophs. Some bacteria are chemosynthetic autotrophs—they get energy for life processes from chemical bonds. Other bacteria are heterotrophs, and absorb the complex nutrients they need from the environment. There are two major groups of bacteria, and some authorities separate one of the groups of bacteria into their own kingdom, producing a total of six kingdoms. For this introductory set of on-line readings we have not followed that classification system, and have kept all the bacteria within the Kingdom Monera.