Kingdom Monera


In the animal world, living things have different sizes and functions within nature . Some of them can become so tiny that they are even invisible to the human eye, but at the same time they are very powerful regardless of their size, this is the case of the Monera kingdom , the kingdom made up of bacteria . The Monera kingdom is a kingdom in biology that comprises prokaryotes , which are single- celled organisms that do not possess a true nucleus. This kingdom is the oldest group of organismsthat has existed on earth, as well as the most numerous .


What is the Monera kingdom?

The Monera kingdom is the kingdom of organisms and microorganisms considered prokaryotes , mainly bacteria that are found throughout the earth’s surface and that due to their structure , have a microscopic size

  • What does it consist of
  • Characteristics of the Monera kingdom
  • Source
  • Evolution
  • Classification of the Monera kingdom
  • Habitat
  • Nutrition
  • Reproduction
  • Breathing
  • Cell types of kingdom Monera
  • Dominion of the Monera kingdom
  • Diseases
  • Examples of organisms
  • Profits
  • Damages
  • Importance

What does it consist of

The Monera kingdom in the area of biology consists of all those different organisms and microorganisms that are characterized mainly by their unicellular formation , in other words, organisms that have only one cell. Although they are a simpler organism than the rest of all living organisms, their presence is much greater than them, mainly because it is considered that there are around 4000 and 9000 different species of prokaryotes or bacteria.


Characteristics of the Monera kingdom

The main characteristics of the Monera kingdom are the following:

  • The bacteria or microorganisms that belong to this group do not have a clearly defined nucleus within their cellular structure .
  • They do not have elements common to the rest of living beings such as mitochondria.
  • They are composed of a single prokaryotic cell , which does not have a defined nucleus.
  • They can be autotrophs capable of creating their own food or they can also be heterotrophic and obtain their food source from other organisms.
  • They are the most primitive group in the world and are part of the five biological kingdoms.
  • They have a rigid cell wall that surrounds the plasma membrane .
  • The genetic material in cells is found floating freely in the cytoplasm.
  • Their reproduction is asexual .
  • They are mobilized by means of cilia or flagella .


In 1866, the German naturalist known as Ernst Haeckel proposed the taxon monera as a phylum and for this reason he is often noted as the first scientist to speak about the kingdom Monera. In this year, Haeckel divided living beings into animals , plants and protists and in the last kingdom he was in charge of including a set of organisms that he called moneras , which would be the simplest of all. In this classification there were also eukaryotes and prokaryotes. In 1969, the last major classification was made with the already accepted monera taxon, it was the classification made by Robert Whittaker .


The Monera kingdom is considered the oldest kingdom of all; and contemporary prokaryotes as the most abundant in the world. Fossils belonging to the Monera kingdom have been discovered in rock strata dating back 3.5 billion years. There is a well-accepted theory that prokaryotic cells began to live permanently inside larger cells and later became the current mitochondria and chloroplasts of eukaryotic cells.. Prokaryotes have been around for a long time and evolved in response to various selection pressures.

Classification of the Monera kingdom

The Monera kingdom is classified as follows:

  • Bacteria : they are the most abundant organisms and include prokaryotic microorganisms , which do not have a defined nucleus . They have different sizes and depending on the species they can vary in size. They are able to survive in extreme environments , in radioactive waste , in the depths of the sea and on land . They can also live on the skin and in the digestive tract , some are harmless or beneficial.
  • Archaea : are microorganisms that define the limits of life on Earth. They have no nucleus and are microscopic . Their cells are wrapped in materials that give them high resistance to antibiotics . They have great biotechnological potential . They can live in extreme environments , in high and low temperatures. They are used for the production of bioplastics.


The different members that make up the Monera kingdom can live individually or they can also live in groups . They can survive and inhabit practically any type of habitat , such as aquatic , terrestrial, and can even inhabit the human body . They are also capable of withstanding temperatures that are quite cold or very high , so they can adapt to living anywhere on the planet. Some of them tend to inhabit internal parts of animalsand they are even beneficial for digestion. But when some of them inhabit animals, they can cause health problems , serious illness and even death .


Nutrition can vary, but it is basically based on two types of nutrition :

  • Autotrophic nutrition : they produce their own food and can be chemosynthetic  and photosynthetic . In chemosynthetic nutrition, bacteria produce their food using inorganic chemicals as an energy source. Chemosynthetics is the method bacteria use when they do not have sunlight.
  • Heterotrophic nutrition : it is when they obtain their food from other organisms . Its main source of nutrition is organic carbon . There are three types of heterotrophic nutrition:
    • Saprophytic nutrition : they feed on decomposing organisms.
    • Parasitic nutrition : they feed on living organisms.
    • Symbiotic nutrition : organic matter is obtained from another living being, benefiting both.


Reproduction in the Monera kingdom is very fast and also quite effective . Most organisms reproduce asexually , multiplying by cleavage or bipartition . Because they have the ability to do this for a short period of time, a bacterium can produce up to a million offspring in a few hours.


The type of breathing that occurs in the Monera kingdom can be of three different types, which are:

  • Obligate aerobes : they are those that must have oxygen in order to survive.
  • Obligatory anaerobes : they are those that cannot survive when oxygen is present.
  • Facultative anaerobes : are those that can survive with or without oxygen.

It is important to mention that some of the bacteria are autotrophic organisms , and for this reason they are able to obtain carbon from carbon dioxide . In turn, organisms that can use light to obtain its energy are known as photoautotrophs . The chemotrophs are the type of bacteria that derive their energy from the inorganic compounds such as hydrogen sulfide and the use of energy to run the cell activities.

Cell types of kingdom Monera

In the Monera kingdom, organisms have cells without a nucleus , they do not have mitochondria , they do not have a nuclear membrane, and they have a rigid cell wall that surrounds the plasma membrane . Some organisms have a slimy layer made up of sugars .

Dominion of the Monera kingdom

With respect to the domain that Monera has in the kingdom, there are two different types that are the bacteria that are the main representatives of the kingdom and the archaea domain .


Among the most common diseases that are caused by organisms of the kingdom Monera mentioned the following:  infections , throat, skin infections, pneumonia , meningitis , dysentery swine, gastritis and ulcers , diseases sexually transmitted infections , diarrhea , gastritis , etc.

Examples of organisms

Some examples of organisms of the Monera kingdom are:

  • Koch’s bacillus
  • Chlamydia
  • Escherichia coli
  • Salmonella
  • Clostridium septicum
  • Neisseria gonorrhoeae
  • Helicobacter pylori
  • Staphylococcus
  • streptococcus


The Monera kingdom includes bacteria that can be favorable because they have the ability to kill organisms that cause pathogenic diseases . They can also be involved in the production of antibiotics , such as streptomycin, which is used to treat infections. They also work as decomposers of plant matter and dead animals, help in bio control in the area of agriculture and in the production of cheese and yogurt .


In the Monera kingdom we find a type of bacteria known as methanogens which generate methane , a gas that damages the environment and has been associated with global warming . These bacteria are present in the intestines of ruminants, and it is they that eliminate methane as a by-product of digestion . Many of them can infect live hosts and cause a number of diseases . 


The importance of moneras is found in the ability they have to interact with other living organisms, either through symbiosis , a process that favors immunity and digestive processes , through the contribution of photosynthesis releasing oxygen into the atmosphere or, on the contrary, due to its ability to cause diseases of different severity.

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