The 8 main characteristics of the Monera Kingdom

There are many living beings that populate the Earth. The different types of animals and plants are probably the first that come to mind when thinking about living things, but not are the only ones: there are other creatures such as fungi or algae, and even many that are invisible to the naked eye, such as bacteria.

The latter are often a reason for fear for the population, as they are associated with dangerous diseases, but It is true that some of them are also part of our bodies and help us carry out processes such as digestion.

When we talk about bacteria, we are talking about one of the main representatives of the Monera kingdom, according to the division into kingdoms of the different living beings. This kingdom, the oldest of all and the first to emerge as well as the most abundant, has a large number of unique properties that distinguish it from other kingdoms. That is why throughout this article We are going to talk about the main characteristics of the kingdom Monera, to understand how are the forms of life that are usually included in this concept.

• Related article: "The 10 branches of Biology: its objectives and characteristics"

What is the Kingdom Monera? A short description

We call kingdom monera a set of living beings classified in the same category due to the similarities between all its members and the differences towards the rest of the set of living beings, following the classification into kingdoms proposed by Ernst Haeckel and later expanded by various authors.

the monera kingdom groups a broad set of unicellular beings without a cell nucleus, whose DNA is scattered in the cytoplasm and characterized by a great simplicity in its configuration (in fact monera comes from the Greek "moneres", simple). This kingdom is what has traditionally been known as the kingdom of bacteria, which can be classified by their shape in cocci. if they resemble spheres, bacilli if they are rod-shaped, spirilla if they resemble a ringlet or a spring, and vibrios if they are shaped like eat.

However, the group of cyanobacteria also forms part of it, which differs from bacteria in that they are unicellular algae capable of photosynthesis, and the of the archaebacteria (which have an internal functioning more similar to the rest of the kingdoms than to that of the bacteria and are capable of surviving in the most extreme).

Interestingly, despite probably being the most primitive group phylogenetically speaking (they were the first inhabitants of the planet) and the one with the greatest presence in the world, was the last to be discovered (although not incorporated into the classification of the kingdoms, this honor corresponding to the kingdom fungi or of the fungus). It was incorporated as its own kingdom by Alexander Barkley in 1939 (although divided and later by Herbert Copeland as we know it today.

However, today the concept of kingdom monera, and even that of kingdom as a classificatory system, is increasingly in disuse. In addition, it has been observed that the representatives of the kingdom Monera should be separated into two: archaea (including the archaebacteria) and bacteria (including both bacteria and cyanobacteria), due to the large differences between these groups.

Main characteristics of the Kingdom Monera

As previously mentioned, the Monera kingdom presents a series of characteristics and particularities that have meant that up to now they have been classified as one of the main types of living beings. In this sense, we can highlight the following characteristics as the most relevant.

1. are prokaryotic organisms

One of the distinctive characteristics of the Monera kingdom is that all of its representatives are prokaryotes, that is, they are living beings that do not have a cell nucleus. Thus, DNA is not condensed and protected by a structure, but is found distributed throughout the cytoplasm of the cell. It is the only one of the kingdoms that presents this characteristic, being the most primitive group of living beings.

• You may be interested in: "The 3 types of bacteria (characteristics and morphology)"

2. circular DNA

Partly linked to the previous point. If we think about DNA, the image of a double helix surely comes to mind, just as it occurs in human DNA strands. However, in the Monera kingdom this type of distribution does not occur, but rather there is a structure in the form of a double circular chain, closed. Interestingly, this structure is also found in the mitochondria of animals as well.

3. They are unicellular

Although animals and plants are made up of millions of cells, moneras They are much simpler organisms that are composed of a single cell.. They do not form tissues or organs, nor do they need them to survive. Despite this, some specimens are grouped into large groups (although they continue to be living beings individually).

4. Asexual reproduction

Another characteristic of this kingdom is that all its components present mostly asexual reproduction and based on mitosis: Bacteria reproduce through binary fission or bipartition, in which the same individual generates copies of its DNA and divides into identical and independent individuals, or budding in which a miniature version of itself is generated on the body and it grows until break off.

However, in some cases a genetic exchange with other bacteria does take place, through contact or through the transformation of DNA within the being itself.

• You may be interested in: "Differences between mitosis and meiosis"

5. scrolling methods

Another aspect to take into account is that although some are immobile, in many cases the Moneras can also move. This is because may have flagella and cilia with which they can move by helical movement or from front to back and vice versa.

6. Size

The components of the kingdom of Moneras They are the smallest creatures that exist (with the possible exception of viruses, if we consider them living things), often no more than a few micrometers.

7. feeding methods

Moneras can have different feeding systems. As a general rule, they are heterotrophic, that is, they feed on external elements or other creatures.. In this sense they can be parasitic, symbiotic or saprophytic (they feed on the residue of other beings).

However, many bacteria and all cyanobacteria are autotrophs, generating the nutrients they need to live from inorganic matter, such as through photosynthesis.

8. Breathing

Most living beings are obligate aerobes, that is, they need oxygen to survive. However, in the kingdom Monera There are specimens that can survive without oxygen (facultative anaerobes) or even for which oxygen is deadly (in fact, one of the first extinctions Massive growths occurred among the obligate anaerobic organisms when this atmosphere began to prevail in our atmosphere. element).

Bibliographic references:

• Campbell, N. (2003). Biology: Concepts & Connections. San Francisco: Pearson Education.
• Margulis, L. and Schwarz, K. v. (1982). Five Kingdoms. An Illustrated Guide to the Phyla of Life on Earth. W.H. Freeman, San Francisco.
• Murat, D.; Byrne, M.; Komeili, A. (2010). Cell Biology of Prokaryotic Organelles.. Cold Spring Harbor Perspectives in Biology 2(10). doi: 10.1101/cshperspect.a000422.