Bdelloid

Information about Bdelloid

Bdelloids
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Scanning electron micrographs showing morphological variation of bdelloid rotifers and their jaws.

Scanning electron micrographs showing morphological variation of bdelloid rotifers and their jaws.
Scientific classification
Kingdom:Animalia
Phylum:Rotifera
Class:Bdelloidea
Hudson, 1884
Order:Bdelloida
Families


Adinetidae
Habrotrochidae
Philodinavidae
Philodinidae
Bdelloidea (IPA: /dəˈlɔɪdiə/) is a class of rotifers found in fresh water and moist soil. Bdelloids typically have a well developed corona, divided into two parts, on a retractable head. They may move by swimming or crawling. The latter commonly involves taking alternate steps with the head and tail, as do certain leeches, which gives the group their name (Greek βδελλα or bdella, meaning leech).

Bdelloids have been of interest to those interested in the evolutionary role of sexual reproduction, because it has disappeared entirely from the group: males are unknown, and females reproduce exclusively by parthenogenesis. Each individual has paired gonads. Despite the fact that they have been asexual for millions of years, they have diversified into more than 300 species and are fairly similar to other sexually-reproducting rotifer species.

Bdelloids respond to environmental stresses by entering a state of dormancy known as anhydrobiosis. This dormancy form enables the organism to rapidly dehydrate itself. The Bdelloid will remain in this cysted state until optimal environmental conditions re-occur at which point they will rehydrate and become active within hours. Diapause is the ability of the organism to produce offspring in a dormant and unhatched state. Hatching of the young will only occur when conditions are at their most favourable. These forms of dormancy are also known as cryptobiosis or quiescence.

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Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. Scientific classification also can be called scientific taxonomy, but should be distinguished from folk taxonomy, which lacks scientific basis.
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Rotifera
Cuvier, 1798

Classes
Monogononta
Digononta
The rotifers make up a phylum of microscopic and near-microscopic pseudocoelomate animals. They were first described by John Harris in 1696 (Hudson and Gosse, 1886).
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This chart shows concisely the most common way in which the International Phonetic Alphabet (IPA) is applied to represent the English language.

See International Phonetic Alphabet for English for a more complete version and Pronunciation respelling for English for phonetic
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Rotifera
Cuvier, 1798

Classes
Monogononta
Digononta
The rotifers make up a phylum of microscopic and near-microscopic pseudocoelomate animals. They were first described by John Harris in 1696 (Hudson and Gosse, 1886).
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Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve.
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Hirudinea
Lamarck, 1818

Genus: Macrobdella

Orders
Arhynchobdellida or Rhynchobdellida
There is some dispute as to whether Hirudinea should be a class itself, or a subclass of the Clitellata.
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Greek}}} 
Writing system: Greek alphabet 
Official status
Official language of:  Greece
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recognised as minority language in parts of:
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Regulated by:
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The evolution of sex is a major puzzle in modern evolutionary biology. Many groups of organisms, notably the majority of animals and plants, reproduce sexually. The evolution of sex contains two related, yet distinct, themes: its origin and its maintenance.
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Parthenogenesis (from the Greek παρθένος parthenos, "virgin", + γένεσις genesis
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The gonad is the organ that makes gametes. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, sperm and egg cells are gametes.
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Cryptobiosis is an ametabolic state of life entered by some lower organisms in response to adverse environmental conditions such as desiccation, freezing, and oxygen deficiency.
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Cryptobiosis is an ametabolic state of life entered by some lower organisms in response to adverse environmental conditions such as desiccation, freezing, and oxygen deficiency.
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Rotaria
Scopoli, 1777

Species

Rotaria citrina Rotaria macrura Rotaria magnacalcarata Rotaria neptunia Rotaria neptunoida Rotaria rotatoria Rotaria socialis Rotaria sordida
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