Classification of Organisms

Classification of Organisms

Organisms are classified in various categories depending on their characteristics. The main three domains of life are archaea, bacteria and eukaryote. These domains are further grouped into various kingdoms. Every kingdom has different characteristics, which formed the basis of their classification. The six kingdoms include; archaebacteria, eubacteria, protista, fungi, plantae and animalia. The major characteristics used in the determining of placements are their metabolism, cell type and reproduction.

Archaebacteria reproduce asexually by budding, binary fusion and fragmentation. Their cell type is prokaryotic and they acquire their nutrients through absorption, chemosynthesis, or non-photosynthetic photophosphorylation. Example of organisms includes halophiles and thermophiles (Huxley, 1970).

Eubacteria reproduce through asexual reproduction and their cell type is prokaryotic. Metabolism takes place depending on the species. Nutrients are intake through chemosynthesis and photosynthesis. Example is actinobacteria and cynobacteria.

Protista have eukaryotic cell type and in their metabolism, they require oxygen. Nutrients are intake through absorption, ingestion and photosynthesis. They produce asexually while others through meiosis. Example is amoeba, brown algae and slime molds.

Fungi have a cell type known as eukaryotic. They require oxygen for metabolism. Nutrients are taken in through absorption and they reproduce through asexual or sexual. Example is mushrooms, molds and yeast.

Plantae requires oxygen for their metabolism and they reproduce through asexually mitosis. Others produce through sexual reproduction, they acquire nutrients through photosynthesis. They fall in the domain of eukayotea and have cell walls with cellulose and chloroplasts. Example is flowering plants, ferns and mosses.

Animalia have eukaryotic cell and require oxygen for metabolism. They acquire nutrients through ingestion, they have sexual reproduction, and examples include mammals, sponges, insects, worms and amphibians.

All these organisms are categorized into 7 taxonomic ranks. This includes the kingdom, phylum/division, class, order, family, genus and species. This classification is defined by the international nomenclature codes.

Reference

Huxley, T. (1970). Lectures on Evolution. New York Tribune. Extra. no 36. In Collected Essays IV: pp 46-1388.