All Moneras are prokaryotic, and all prokaryotes are classified as Monera. A prokaryotic cell differs from a eukaroytic cell because a prokaryote does not have its DNA in a specialized organelle (eukaryotes have their DNA in an organelle called the nucleus). Prokaryotes instead store their DNA in an area called the nucleoid region, which is not separated from other parts of the cell. Additionally, prokaryotes all reproduce asexually; a single Monera creates two new organisms when it splits in half through the process of binary fission.
Monera are very diverse in their food sources. Some are animal-like in that they consume nutrients from other organic material, and they use flagella (whip-like appendages on the exterior of the cell) to chase down their food. Others are plant-like in that they use a primitive form of photosynthesis to make nutrients (scientists believe that the evolutionary source of chlorophyll in plants come from single-cell organisms). Some Monera get their food in ways that no other non-Monera organisms can do, such as the Chemilithotrophic species of bacteria, which oxidizes inorganic substances in order to get carbon.
Almost all bacteria that people encounter on a day-to-day basis is eubacteria. All bacterial infections in human beings are caused by eubacteria because several species of eubacteria survive through parasitism (they attach themselves to a host organism and draw out nutrients). Eubacteria are generally classified based on how they react to the Gram stain test (Gram positive bacteria turn purple when stained; Gram negative bacteria turn reddish). About 75% of eubacteria are Gram negative.
Archaeabacteria (or just Archaea) are a relatively newly discovered group of organisms. Their defining feature is the ability to live in climates that are considered inhospitable to most other forms of life. For example, they have been found on the ocean bottom in extremely hot deep sea vents and in extremely salty ocean water. Their food sources vary dramatically; the ones found in the deep sea vents use carbon dioxide to produce methane in order to survive. Scientists believe that Archaea may be the original life forms that developed on Earth.