Difference Between Kingdom and Domain

The key difference between kingdom and domain is that the kingdom is one of the five major groups of living organisms while the domain is one of the three taxonomic categories of living organisms above the kingdom level.

There were many attempts at the classification of organisms on earth. Till 1977, the kingdom system was universally accepted across the world.

Starting from the two kingdoms system called the Linnaean system way back in 1758 when the life forms were divided into plants and animals, the world has come to recognize the three-domain system as the most current and the most scientific system of classification of organisms.

Though there are some similarities, the kingdom system of classification of organisms has now been relegated to having relatively little significance since the three-domain system was popularized in all parts of the world. The aim of this article is to find out the difference between kingdom and domain systems of classification of organisms.

What is Kingdom?

The old two-kingdom system of classification comprised two kingdoms; plant kingdom and animal kingdom. A Linnaean system called all organisms that moved with the anima (with a soul), and fungi got classified as plants.

The system went on adding kingdoms. However, the five-kingdom classification system was believed to be the complete system after the discovery of bacteria, algae, and electron microscope.

Hence, the five-kingdom classification proposed in 1969, is the most updated system of classification today even though the six-kingdom classification is more accurate. Plantae, Archaebacteria, Eubacteria, Protista, Animalia, and Fungi are the six-kingdom included in the six-kingdom classification.

In this classification system, the fifth kingdom; Monera has been divided into Archaebacteria and Eubacteria; thus, bringing the number of kingdoms to six. The five-kingdom classification includes five kingdoms namely Monera, Protista, Fungi, Plantae, and Animalia.

In all classifications, whether 5 or 6 kingdoms, a kingdom has subdivisions such as phyla or divisions. In fact, Kingdom Animalia consists of phyla while the Kingdom Plantae has divisions.

What is Domain?

Two scientists, Woese and Wolfe, 1977, completely changed the system of classification of organisms in the world when they made use of 165 ribosomal RNA sequences. Till 1977, the world had come to accept the bifurcation of life forms into eukaryotes and prokaryotes.

But it was the discovery of archaea; the microorganism that could live without oxygen, so reminded one of the ancient environment of earth that was devoid of oxygen, that forced scientists to conceive of a third category of organisms.

Therefore, Archaea was accepted as being different from the earlier two classifications, and thus the three-domain system came into existence. Accordingly, the three domains include Bacteria, Archaea and Eukarya.

What are the Similarities Between Kingdom and Domain?

There are a few similarities between the kingdom and domain levels of classification in biology:

  • Both the kingdom and domain are levels of classification used to group living organisms based on their evolutionary relationships and characteristics.
  • Both the kingdom and domain are used to help scientists understand the diversity of life on Earth and how different species are related to one another.
  • Both the kingdom and domain are used to facilitate the communication and study of specific groups of organisms.
  • Both the kingdom and domain are constantly evolving as new information is discovered about the relationships and characteristics of different species.
  • Both the kingdom and domain are hierarchical, with the domain being the highest level of classification and the kingdom being a lower level of classification.

What is the Difference Between Kingdom and Domain?

Three domains or five kingdoms are two types of classification systems to categorize living organisms. There are several differences between the kingdom and domain levels of classification in biology:

Classification level. The domain is the highest level of classification, while the kingdom is a lower level of classification.

Evolutionary history and characteristics. The organisms within each domain and kingdom have different evolutionary histories and characteristics that distinguish them from other groups. For example, the domain Bacteria includes all prokaryotic organisms, while the kingdom Plantae includes all eukaryotic organisms that are characterized by their ability to photosynthesize and their cell walls made of cellulose.

A number of categories. There are three categories within the domain (Bacteria, Archaea, and Eukarya) and six categories within the kingdom (Monera, Protista, Fungi, Plantae, Animalia, and Chromista).

The breadth of classification. The domain is a more broad level of classification than the kingdom, as it groups organisms into three broad categories based on their evolutionary relationships and characteristics. The kingdom is a more specific level of classification, as it groups organisms into six more specific categories based on their evolutionary relationships and characteristics.

Share On:

Related Posts

What Others Are Asking