phylum

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phylum,

in taxonomy: see classificationclassification,
in biology, the systematic categorization of organisms into a coherent scheme. The original purpose of biological classification, or systematics, was to organize the vast number of known plants and animals into categories that could be named, remembered, and
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.

Phylum

 

(also type), the highest taxonomic category in the classification of animals. A phylum, or type, is made up of related classes. The term “type” was proposed in 1825 by H. de Blain-ville, who applied it to the four “branches” of animals distinguished by G. Cuvier in 1812.

Phyla vary in size: for example, the phylum Porifera comprises approximately 5,000 species, whereas the phylum Pogonophora has only about 100 species. Phyla are frequently divided into sub-phyla. For example, the phylum Chordata has four sub-phyla—Cephalochordata, Tunicata, Acrania, and Vertebrata. Organisms belonging to the same phylum are marked by the same structural organization. The number of phyla and their size vary from one classification system to another. Some taxonomists recognize as few as ten phyla, and others as many as 33. However, these differences do not diminish the importance of phyla as categories that reflect the principal branches of the phylogenetic tree of the animal kingdom.

In plant classification, which has been worked out independently from animal classification, the taxonomic category corresponding to a phylum is called a division.

M. E. KIRPICHNIKOV

phylum

[′fī·ləm]
(systematics)
A major taxonomic category in classifying animals (and plants in some systems), composed of groups of related classes.

phylum

a major taxonomic division of living organisms that contain one or more classes. An example is the phylum Arthropoda (insects, crustaceans, arachnids, etc., and myriapods)
References in periodicals archive ?
Class-level Order-level and Family level distribution of different phyla encountered in rhizosphere soil
However, not all living animal phyla with a fossil record first appear within this time window.
Some known genera were represented in these "minor phyla" The most abundant of the minor phyla, Chloroflexi, comprised 372 sequences.
This lab exercise is a great way to present the invertebrate phyla in a few hours.
When considering the great species richness of the insects, whose estimated numbers range from 2 to 35 million species, one forgets that this taxon represents only a part of the total number (albeit a large part) of invertebrates - a grouping that contains between 25 and 30 major phyla. New presents in tabular form a sobering and daunting picture of the situation.
Cuvier's eye for detail was such that he could tell whether fossil remains represented animals that belonged to one or another of the known phyla even though they were not members of any living species.
Decisionmakers carried out a merger in 2012 to 2013 which ultimately reduced the number of co-operatives from 118 to 93, in order to cover up mismanagement, he said and named as an example the Ayia Phyla co-operative which was rocked by the revelations of a fraud case three years ago.
Such a study of even a single species could occupy an entire career, he says, so he selects a few example phyla and species.
Treatment C showed the greatest number of phyla and genera.
Bacterial tags of constipation and 0.1% Gln group covered more than 32 phyla, 81 classes, 118 orders, 168 families, and 195 genera.