Kingdom Monera

What is the Kingdom Monera?

The kingdom Monera is the name of a classification of living beings that grouped prokaryotic unicellular organisms and it was composed mainly of bacteria and archaea, the most abundant life forms on the planet.

Prokaryotic organisms are composed of a single cell without a defined nucleus. In fact, the word monera comes from the Greek coins, which refers to the “simple” and “solitary”. Hence, he used to describe the organisms of this kingdom.

Currently, the kingdom Monera is not considered one of the seven kingdoms of nature. These organisms are now classified into two different kingdoms: Archaea (kingdom Archaea) and bacteria (kingdom Bacterium).

But why was Monera considered a separate kingdom for so long? In 1866, the German naturalist Ernst Haeckel had divided living beings into three large groups: animalia, plants Y protist.

The organisms of the Monera kingdom were part of the Protista kingdom in one of its subdivisions, in which the eukaryotic cell organisms were also included.

But later, in the year 1920, the French biologist Édouard Chatton discovered the existence of cells without a defined nucleus and established two groups of cells that he named eukaryotes and prokaryotes.

Subsequently, Hebert Copeland, an American biologist, proposed in 1938 the creation of the kingdom Monera, in which prokaryotic organisms were.

You may be interested:  What is Science

However, in the 1970s, the American microbiologist Carl Woese noticed that two different groups existed within the Monera kingdom: bacteria and archaea, giving rise to the creation of two new kingdoms, with which Monera ceased to exist. be considered a kingdom unto itself.

Characteristics of the kingdom Monera

Draft-ID-Kingdoms of Nature-Do Not Publish

Bacterium Escherichia colicausing gastrointestinal infections.

Among the general characteristics that differentiate the organisms that belong to the Monera kingdom, the following can be named:

  • are prokaryotic cells: that is, they lack a cell nucleus.
  • They are the smallest cellular organisms that have been found, between 0.2 and 3 microns in diameter.
  • Your respiration can be aerobic or anaerobic.that is, that some of the bacteria in this kingdom need oxygen to exist and others do not.
  • They can live individually or in a groupsuch as colony-forming bacteria.
  • They can move autonomouslythanks to the cilia and flagella that some of these organisms have.
  • Its habitat is variedcan be found both on land and in water, on and within other living beings.
  • They reproduce asexuallyby division or bipartition.
  • Nutrition is usually heterotrophicThey depend on other organisms for their livelihood. In some cases it is autotrophic when they can synthesize their own nutrients.
  • The morphology is variedSome are round, stick-shaped or corkscrew-shaped.

Classification of the kingdom Monera

The classification of bacteria has changed over the years thanks to new findings made by scientists. In principle there were two classifications, bacteria and cyanobacteria.

Then the classification proposed by Woese was used, which was made up of four divisions:

You may be interested:  Meaning of Scientific Text


They are unicellular prokaryotic microorganisms. Its name was due to its similarity to bacteria, although today it is known that they are different organisms and even have their own kingdom (Archaea).

Some examples of archaebacteria are the methanogenic archaea, the crenarchaeota, and the halobacteria.

gram positive

They are prokaryotic microorganisms with a cell wall rich in peptodoglycan, a network of amino acids and sugars that protects the cell membrane of the bacteria.

Examples of this type of microorganisms are lactobacilli, micrococci, staphylococci and actinobacteria.

gram negative

They are bacteria whose cell wall is poor in peptidoglycan but rich in lipids.

Meningococci, Chlamydia, and intestinal bacteria, such as Escherichia coliare some examples.


They are bacteria that do not have a cell wall, very difficult to detect under the microscope due to their almost imperceptible size. Some of them are pathogenic parasites of vertebrates, including humans.

Examples of mycoplasmas are anaeroplasmatales, entomoplasmatales, mycoplasmatales bacteria and the Mycoplasma pneumoniaewhich can cause pneumonia in humans.

Examples from the kingdom Monera

Draft-ID-Kingdoms of Nature-Do Not Publish

Clostridium botulinumthe bacterium that causes botulism.

Below are some examples of the organisms that were considered to be part of the kingdom Monera, which are largely bacteria.

  • C.hlamydia trachomatis: Gram negative bacterium that causes sexually transmitted infections.
  • vibrio vulnificus: is a Gram negative bacterium that causes infections in humans.
  • bifidobacteria: bacteria found in the colon and involved in digestion.
  • Escherichia coli: bacterium that causes gastrointestinal infections.
  • Lactobacillus casei: is a Gram positive bacterium, produces lactic acid and is found in the intestines and mouths of humans.
  • Clostridium botulinum: is a bacillus that is found in the soil and that generates the toxin that causes botulism.
You may be interested:  Meaning of Molar Mass

See also:

  • kingdoms of nature
  • animal Kingdom
  • Kingdom Plantae
  • fungi kingdom
  • protist kingdom
  • Classification of living things into domains and kingdoms