How Many Kingdoms are There in Biology

Introduction

There are five types of Kingdoms in biology. Classification is a process that groups organisms based on similarities and differences. It systematically simplifies the study of a large range of species. In 1969, R.H. Whittaker suggested the five-kingdom division based on certain characteristics, including method of feeding, thallus organisation, cell structure, evolutionary connections, and reproduction, all of these served as the basis for this categorization. Five types of kingdom classification are Monera, Protista, Fungi, Plantae, and Animalia.

Classification oof Kingdoms

The taxonomy of living beings did not initially produce the five-kingdom division that we observe today. The first two kingdoms, Plantae and Animalia were categorised by Carolus Linnaeus.

The two-kingdom categorization was in place for a very long period, but it was not permanent since it did not consider many important factors. Eukaryotes and prokaryotes, unicellular and multicellular organisms, and photosynthetic and non-photosynthetic organisms could not be distinguished from one another.

There were many species that could not be classed as either plants or animals, thus just placing all the organisms in the plant or animal kingdom was inadequate.

Due to the misunderstanding, a new categorization system was developed that had to take into consideration factors including cell wall existence, cell structure, mechanism of reproduction, and mode of nourishment. R. H. Whittaker developed the five-kingdom categorization as a consequence.

These kingdoms are as follows:

Kingdom Monera

In Kingdom Monera, bacteria are included.

Characteristics of Monerans:

• Bacteria are minute organisms that are present everywhere.

• Monerans have cell walls and are prokaryotic.

• A combination of polysaccharides and amino acids make up the cell wall.

• Both heterotrophic and autotrophic bacteria exist.

• Bacteria that produce heterotrophic food might be saprophytic or parasitic.

Based on their form, Monerans bacteria can be divided into four types:

• Coccus - These are spherical shaped.

• Bacillus - These are rod-shaped bacteria.

• Vibrium - These are comma-shaped.

• Spirillum - These are spiral-shaped.

Kingdom Protista

characteristics of protista:

• They are eukaryotic, unicellular creatures.

• For locomotion, some of them contain cilia or flagella.

• Cell fusion and zygote development are the processes used in sexual reproduction.

Protists are divided into the following subgroup groups:

• Chrysophytes: This class of organisms includes diatoms and golden algae (desmids). They can be found in both freshwater and the ocean.

• Dinoflagellates are typically marine, photosynthetic organisms. They can appear as red, blue, brown, green, or yellow depending on the primary pigments in their cells.

• Euglenoids: The majority of them inhabit freshwater habitats with still water. They don't have a cell wall; instead, they have a pellicle, which has a rich layer of protein.

• Slime Moulds: These grow on their own. Their body glides across rotting branches and leaves while feeding organic matter. They clump together in a favourable environment and were formerly known as Plasmodial slime moulds.

• The heterotrophic protozoans live either as parasites or as predators.

Kingdom Fungi

Moulds, mushrooms, and yeast are all members of the kingdom fungi. They are used for various household and commercial purposes.

Characteristics of Fungi :

• Yeast is single-celled otherwise all the members of Kingdom Fungi are filamentous.

• Their body is made up of hyphae, which are long, thin constructions that resemble threads. Mycelium is the name given to the hyphal web.

• Unbroken tubes that are packed with multinucleated cytoplasm make up some of the hyphae.

• The second kind of hyphae has septae, or cross-walls.

• In fungi, chitin and polysaccharides make up the cell wall.

• Most of the fungi are heterotrophic and saprophytes.

• Some of the fungi continue to exist as symbionts. Some of them are pests. Some of the symbiotic fungi, such as lichens, live with algae.

• Certain symbiotic fungi coexist with the roots of higher plants like mycorrhiza.

Kingdom Plantae

Characteristics of Kingdom Plantae are as follows:

• The entirety of the eukaryotes containing chloroplasts belongs to the kingdom Plantae.

• Although some of them are heterotrophic as well, autotrophs make up the majority of them.

• Most of the cell walls are made up of cellulose.

• Plants have two main lifespan periods. These stages switch off one after the other, the haploid gametophytic phase and the diploid saprophytic stage. Diverse kinds of plants have different diploid and haploid phase durations. This process is referred to as the Alternation of Generation.

Kingdom Animalia

Characteristics of Kingdom Animalia are:

• This kingdom includes all heterotrophic multicellular eukaryotes without cell walls.

• Animals rely on plants either directly or indirectly for their nourishment. Holozoic nutrition is their style of eating. Holozoic feeding includes both the consumption of food and the subsequent use of an internal cavity for food digestion.

• Many of the creatures are skilled in moving.

• They reproduce mostly through sexual means.

Conclusion

The five-kingdom method of classifying living things took many factors into account and is still the most effective one.

In the previous categorization scheme, two extremely diverse creatures were placed together based only on that one trait. For instance, the existence of the cell wall led to the fungus and plants being grouped. A similar method was used to combine multicellular and unicellular creatures.

As a result, all species were once again divided into the five kingdoms of the five-kingdom classification, beginning with Monera, which included all prokaryotic unicellular organisms.

After then, the kingdom Protista was given to all eukaryotic unicellular creatures.

Following that, the organisms were categorised according to whether they had a cell wall or not. Animalia was the kingdom for those without cell walls, while Plantae was the realm for those with cell walls.

Plantae and fungi were included in the categories of photosynthetic and non-photosynthetic organisms under the kingdom Plantae because it eliminated the complication of placing one species in two separate kingdoms, this way of classifying living things is preferable to the traditional categorization of plants and animals.