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The following is a list of the classes in each phylum of the kingdom Animalia. There are 107 classes of animals in 33 phyla in this list. However, different sources give different numbers of classes and phyla. For example, Protura, Diplura, and Collembola are often considered to be the three orders in the class Entognatha. This list should by ...
There are seven main taxonomic ranks: kingdom, phylum or division, class, order, family, genus, and species. In addition, domain (proposed by Carl Woese ) is now widely used as a fundamental rank, although it is not mentioned in any of the nomenclature codes, and is a synonym for dominion ( Latin : dominium ), introduced by Moore in 1974.
Some groups have two unicellular ocelli (simple eyes). [18] [20] The epidermis of all species within the phylum is ciliated. The cilia are composed of a set of nine pairs of peripheral microtubules and one or two central microtubules (patterns 9+1 and 9+2, respectively). The pairs 4–7 terminate before the tip, creating a structure called a ...
The term phylum was coined in 1866 by Ernst Haeckel from the Greek phylon (φῦλον, "race, stock"), related to phyle (φυλή, "tribe, clan"). [4] [5] Haeckel noted that species constantly evolved into new species that seemed to retain few consistent features among themselves and therefore few features that distinguished them as a group ("a self-contained unity"): "perhaps such a real and ...
Later two further main ranks were introduced, making the sequence kingdom, phylum or division, class, order, family, genus and species. [4] In 1990, the rank of domain was introduced above kingdom. [5] Prefixes can be added so subkingdom (subregnum) and infrakingdom (also known as infraregnum) are the two ranks immediately below kingdom ...
John Hogg's illustration of the Four Kingdoms of Nature, showing "Primigenal" as a greenish haze at the base of the Animals and Plants, 1860. As a phylum under Animalia, the Protozoa were firmly rooted in a simplistic "two-kingdom" concept of life, according to which all living beings were classified as either animals or plants.
Each lipophil cell contains numerous middle-sized granules, one of which is a secretory granule. [34] [33] The body axes of Hoilungia and Trichoplax are overtly similar to the oral–aboral axis of cnidarians, [35] animals from another phylum with which they are most closely related. [36]
The relative number of species contributed to the total by each phylum of animals. Arthropoda is the phylum with the most individual organisms. Bilateria is an extremely diverse group of animals containing a vast majority of its species, largely due to the enormous amount of arthropods. This article is a list of orders contained within ...