Monera is one of the five kingdoms, or super-groupings, that scientists use to classify living creatures. Specifically, the monera kingdom comprises all prokaryotes, such as blue-green algae, primitive pathogens, and other single-celled organisms with free-floating genetic material. Bacteria belong to this kingdom.
Numerous classifications exist for monera bacteria, but a common one is this: archaebacteria, which are some of the oldest living organisms; mycoplasmas, which some of the smallest living organisms and lack a cell wall; and eubacteria, or "true bacteria." On a more microscopic level, monera bacteria distinguish themselves by their shape, need for oxygen, reaction to the Gram test, food production and phyla.
Monera bacteria generally take one of three basic shapes: Cocci are shaped like spheres, bacilli are shaped like rods, and spirilla are shaped like spirals. Other types of monerans are pleomorphic, which means that they can appear in several shapes. For example, Mycobacterium tuberculosis, a culprit behind tuberculosis, can be either spherical or rod-shaped.
A bacterium's shape is also called its morphology.
Need for Oxygen
Monera bacteria can be anaerobic or aerobic. Aerobic bacteria require oxygen, such as "nitrogen-fixing" bacteria, which live in the earth's soil and convert nitrogen gas into ammonium. Oxygen, however, causes anaerobic bacteria to dwindle. One example is the bacteria in propionic acid, which forms the holes in Swiss cheese. Yet other bacteria are facultative, meaning they can survive with or without oxygen.
Reaction to the Gram Test
Some monera bacteria contain high amounts of peptidoglycan, a substance that gives strength and shape to their cells walls. To detect these bacteria, scientists generally turn first to the Gram test, which goes like this:
To begin, scientists stain a bacteria sample with crystal violet, a dark purplish chemical. Then, they rinse that sample and apply other chemicals for stability and color contrast. If the bacteria holds the stain, they are "Gram positive" and have cell walls rich in peptidoglycan. This quality distinguishes them from "Gram negative" bacteria, which have either low peptidoglycan content or an outer membrane that resists crystal-violet.
Gram positive and Gram negative are some of the most basic classifications for monera bacteria.
Monera bacteria nourish themselves in one of two ways: Autotrophic bacteria, or autotrophs, produce their own food through direct sources of energy. One special type of autotrophs are called "photoautotrophs." Like green plants, these bacteria can produce their own food by absorbing the sun's rays. Other autotrophs live in extreme environments, for example near active volcanoes or on the ocean floor.
Heterotrophs, on the other hand, must search out organic forms of carbon. Unlike autotrophs, they cannot produce their own food.
Phyla depends on the bacteria's genetic makeup. Scientists currently recognize 15 phyla, which range from Aquificae, which live in hot springs and ocean vents, to Verrucomicrobia, which are common in soil.