Topic:Five Kingdom Classification System
Submitted To: Mam Samina Submitted By: Shahid Zafar Registration No: 2013-ag-2212 Section: B Community College University of Agriculture Faisalabad (Pars Campus)
Five Kingdom Classification System
Definition and Associated Terms
When Carl Linnaeus introduced the rank-based system of nomenclature into biology, the highest rank was given the name "kingdom" and was followed by four other main or principal ranks: the class, order, and genus. Later two further main ranks were introduced, making the sequence kingdom, phylum or division, class, order, family, genus and species. In the 1960s a rank was introduced above kingdom, namelydomain (or empire), so that kingdom is no longer the highest rank. Prefixes can be added so subkingdom and infrakingdom are the two ranks immediately below kingdom. Superkingdom may be considered as an equivalent of domain or empire or as an independent rank between kingdom and domain or subdomain. In some classification systems the additional rank branch (Latin: ramus) can be inserted between subkingdom and infrakingdom (e.g. Protostomia and Dueterstomia in the classification of Cavalier-Smith). Because of its position, branch can be considered as a minor rank of the kingdom group even if it is not etymologically derived from it. Systems of classification
The classification of living things into animals and plants is an ancient one. Aristotle (384–322 BC) classified animal species in his History of Animals, while his pupilTheophrastus (c. 371–c. 287 BC) wrote a parallel work, the Historia Plantarum, on plants . Carolus Linnaeus (1707–1778) laid the foundations for modern biological nomenclature, now regulated by the Nomenclature Codes, in 1735. He distinguished two kingdoms of living things: Regnum Animale ('animal kingdom') and Regnum Vegetabile ('vegetable kingdom', for plants). Linnaeus also included minerals in his classification system, placing them in a third kingdom, Regnum Lapideum.
In 1674, Antonie van Leeuwenhoek, often called the "father of microscopy", sent the Royal Society of London a copy of his first observations of microscopic single-celled organisms. Until then, the existence of such microscopic organisms was entirely unknown. Despite this, Linnaeus did not include any microscopic creatures in his original taxonomy. At first, microscopic organisms were classified within the animal and plant kingdoms. However, by the mid-19th century, it had become clear to many that "the existing dichotomy of the plant and animal kingdoms [had become] rapidly blurred at its boundaries and outmoded". In 1866, Ernst Haeckel proposed a third kingdom of life, the Protista, for "neutral organisms" which were neither animal nor plant. Haeckel revised the content of this kingdom a number of times before settling on a division based on whether organisms were unicellular (Protista) or multicellular (animals and plants).
The development of the electron microscope revealed important distinctions between those unicellular organisms whose cells do not have a distinct nucleus (prokaryotes) and those unicellular and multicellular organisms whose cells do have a distinct nucleus (eukaryotes). In 1938, Herbert F. Copeland proposed a four-kingdom classification, elevating the protist classes of bacteria (Monera) and blue-green algae (Phycochromacea) to phyla in the novel Kingdom Monera. The...
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