In biological classification, class (Latin: classis) is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank.[a] Other well-known ranks in descending order of size are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order.
The class as a distinct rank of biological classification having its own distinctive name (and not just called a top-level genus (genus summum)) was first introduced by the French botanist Joseph Pitton de Tournefort in his classification of plants that appeared in his Eléments de botanique, 1694.
Insofar as a general definition of a class is available, it has historically been conceived as embracing taxa that combine a distinct grade of organization -- i.e. a 'level of complexity', measured in terms of how differentiated their organ systems are into distinct regions or sub-organs -- with a distinct type of construction, which is to say a particular layout of organ systems. This said, the composition of each class is ultimately determined by the subjective judgement of taxonomists. Often there is no exact agreement, with different taxonomists taking different positions. There are no objective rules for describing a class, but for well-known animals there is likely to be consensus.
In the first edition of his Systema Naturae (1735). Carl Linnaeus divided all three of his kingdoms of Nature (minerals, plants, and animals) into classes. Only in the animal kingdom are Linnaeus's classes similar to the classes used today; his classes and orders of plants were never intended to represent natural groups, but rather to provide a convenient "artificial key" according to his Systema Sexuale, largely based on the arrangement of flowers. In botany, classes are now rarely discussed. Since the first publication of the APG system in 1998, which proposed a taxonomy of the flowering plants up to the level of orders, many sources have preferred to treat ranks higher than orders as informal clades. Where formal ranks have been assigned, the ranks have been reduced to a very much lower level, e.g. class Equisitopsida for the land plants, with the major divisions within the class assigned to subclasses and superorders.
As for the other principal ranks, Classes can be grouped and subdivided. Here are some examples.[b]
|Name||Meaning of prefix||Example 1||Example 2||Example 3||Example 4|
|Subterclass||subter: below, underneath||Colobognatha|
|Parvclass||parvus: small, unimportant||Neornithes|
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Fetal bovine serum (FBS) comes from the blood drawn from a bovine fetus via a closed system of collection at the slaughterhouse. Fetal bovine serum is the most widely used serum-supplement for the in vitro cell culture of eukaryotic cells. This is due to it having a very low level of antibodies and containing more growth factors, allowing for versatility in many different cell culture applications.
The globular protein, bovine serum albumin (BSA), is a major component of fetal bovine serum. The rich variety of proteins in fetal bovine serum maintains cultured cells in a medium in which they can survive, grow, and divide.
FBS is not a fully defined media component, and as such may vary in composition between batches. As a result, serum free and chemically defined media (CDM) have been developed as a matter of good laboratory practice.Guhanagari A Book on Urban Wildlife
Guhanagari: A Book on Urban Wildlife is an attempt to show the diversity of life in Christ University, Bangalore. The book documents from the migratory fluttering butterflies to mammals living inside the 25 acre university campus.The work was done, while they were students of Christ University, Bangalore campus.Istanbul High School
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İstanbul Lisesi is located in Cağaloğlu, İstanbul. The school has changed several buildings throughout its history. Since 1933 the school has used its current building. The building was designed by architects Alexander Vallaury and Raimondo D'Aronco and inaugurated in 1882 as the Düyun-u Umumiye (Council of Ottoman Revenues and Debts Administration) Building, which overlooks the entrance to the Bosphorus and the Golden Horn. A new building adjacent to the main historical building was inaugurated in 1984, providing new boarding and sports facilities. The primary languages of instruction are Turkish and German. The secondary foreign language of instruction is English.Pink whipray
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Gregarious in nature, the pink whipray has been known to form large active and resting aggregations, and associate with other large ray species. It preys mainly on prawns, but also consumes other benthic invertebrates and bony fishes. This species is aplacental viviparous, in which the unborn young are nourished by histotroph ("uterine milk") produced by the mother. Across much of its range, substantial numbers of pink whiprays are caught incidentally by a variety of fishing gear and marketed for meat, skin, and cartilage. It is also of importance to ecotourism, being attracted to visitors with bait. The International Union for Conservation of Nature (IUCN) has listed this species under Least Concern, due to its wide distribution that includes relatively protected areas, such as northern Australia. However, its population in Southeast Asia is likely declining under heavy fishing pressure, and there it has been assessed as Vulnerable.Schauenberg's index
Schauenberg's index is the ratio of skull length to cranial capacity.
This index was introduced by Paul Schauenberg in 1969 as a method to identify European wildcat (Felis silvestris) skulls and distinguish them from domestic cat (Felis catus) skulls.