- Kingdom is a taxonomic rank in biology that is made up of more compact groups called phyla (or divisions, in plants).
The 8 kingdom classification, by Cavalier-Smith includes the following kingdoms:
Eubacteria are prokaryotic microorganisms that have a single cell that lacks a nucleus and one circular chromosome that contains DNA.
- The oldest known living things on earth are archaebacteria.
- They are categorised as bacteria because, when viewed under a microscope, they resemble bacteria and are members of the Monera kingdom.
One of the kingdom-level taxa postulated by Cavallier-Smith, which is thought to be an intermediate form between prokaryotes and eukaryotes because it contains the oldest unicellular eukaryotes with a nucleus and rod-shaped chromosomes but no mitochondria or plastid.
- A category of single-celled eukaryotes that feed on organic substances, such as other microbes or organic tissues and waste, are known collectively as protozoa.
- They can be parasitic or free-living.
Chromista is a kingdom of eukaryotic organisms that includes single-celled and multicellular species that have comparable characteristics in their photosynthetic organelles (plastids).
- All plants are included in Kingdom Plantae.
- These organisms are eukaryotic, multicellular, and autotrophic.
- A stiff cell wall can be found in plant cells.
- The pigment chlorophyll and chloroplast found in plants are necessary for photosynthesis.
Fungi are eukaryotic organisms that include microorganisms such as yeasts, moulds and mushrooms.
- Kingdom Animalia constitutes all animals. Amongst the five kingdoms, the largest kingdom is the animal kingdom.
- Animals are multicellular eukaryotes.
- However, like plants, they do not possess chlorophyll or a cell wall.
- Therefore, members of the animal kingdom exhibit a heterotrophic mode of nutrition.