An important chapter in classes 9 and 11, is the one on the biological classification of species. The broad division of five kingdoms was first introduced by Robert Whittaker. The first kingdom is that of the bacteria comprising prokaryotes called kingdom monera. In the article below, the general features of monerans, some examples and a discussion about bacteria take place.

Classification according to Hackel

Under the classification of Hackel, things were divided into plants and animals; that is kingdom Plantae and kingdom Animalia. 

The word for kingdom monera is derived from the Greek word moneres, which Hackel said meant simple. But later it was found that it meant single or solitary.

What are monerans?

Monerans form the biological kingdom composed of prokaryotes which are bacteria. Now, these organisms do not have a well-defined body and are just made up of a single cell and lack a nucleus. Carl Woese further divided the kingdom monera under two sections called bacteria and archaea respectively.

Eubacteria

Eubacteria is a member of the kingdom monera which translates to ‘true bacteria’ or ‘bacteria’. They are generally found in every habitat. Eubacteria is important in agriculture and medicine. Some monerans from this category are Lactobacilli and E.Coli.

Archaebacteria

They are presupposed to be ancient forms of bacteria and blue-green algae hence the name archaebacteria. Generally, these forms of bacteria thrive in extremely hot climates.

Some monerans from this category are methanogens and thermophiles.

Some general characteristics of the kingdom monera

• They are unicellular organisms, which means single-celled organisms.
• Their genetic material is not enveloped by a sheath and neither is it encased in the nucleus.
• Monerans obtain nutrition from absorption, photosynthesis and chemical synthesis.
• Monerans are generally non-motile and if they do move they do so with the help of flagella.

Different shapes of bacteria

1. Cocci: These types of bacteria are round in shape.
2. Bacilli: These bacteria are shaped like a rod.
3. Vibrios: These kinds of bacteria are shaped like a comma. They are generally motile. 
4. Spirillum: These types are spiral. They are motile too and have flagella present at both ends.

What is the structure of bacteria?

1. Capsule: A slimy layer or capsule is present on some bacteria outside their cell walls. They also encompass some amino acids and nutrients. These capsulated bacteria are generally considered virulent, which means, disease-causing. Some examples include mycobacterium tuberculosis and anthracite.
2. Cell wall: Almost all bacteria in the kingdom monera have a rigid cell wall. The cell wall is composed of proteins and lipids.
3. Plasma Membrane: Situated on the inner side of the cell wall, it is a thin and selectively permeable membrane.
4. Cytoplasm: Any cell is composed of a sappy matrix that contains the rest of the components of the cell and is called the cytoplasm. It is generally made up of enzymes and lipids.
5. Nucleoid: Instead of a nucleus, like other cells, a nucleoid lacks a clearly defined nuclear membrane and the genetic material is present without any sheath. 
6. Flagella: These are thin appendages rising from a cell body. They help the bacteria attain motility.

Cyanobacteria

Often called blue-green algae, this member of the monerans is considered one of the most important ones in the ecology. They not only add oxygen to the atmosphere but also fix the nitrogen in the atmosphere. Cyanobacteria can make their food and is photosynthetic. Some the types of cyanobacteria have a symbiotic relationship with other plants and animals. Their association with plant roots makes it easier for them to fix nitrogen in the atmosphere.

Conclusion

In the above sections, we came to know what organisms comprise the kingdom monera and what are the general characteristics of monerans, their nutrition methods and a few examples of monerans were also discussed.