Chlamydomonadales

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Chlamydomonadales
Volvocales.png
(A) Gonium pectorale, (B) Eudorina elegans, (C) Pleodorina californica, and (D) Volvox carteri
Scientific classification OOjs UI icon edit-ltr.svg
(unranked): Viridiplantae
Division: Chlorophyta
Class: Chlorophyceae
Order: Chlamydomonadales
Fritsch in West & Fritsch, 1927
Families

See text.

Synonyms
  • Volvocida Francé, 1894, orth. zool.
  • Phytomonadina Blochmann, 1895
  • Volvocales Oltmanns, 1904

Chlamydomonadales, also known as Volvocales, are an order of flagellated or pseudociliated green algae, specifically of the Chlorophyceae. [1] Chlamydomonadales can form planar or spherical colonies. These vary from Gonium (four to 32 cells) up to Volvox (500 cells or more). Each cell has two flagella, and is similar in appearance to Chlamydomonas , with the flagella throughout the colony moving in coordination.[ citation needed ]

Both asexual and sexual reproduction occur. In the former, cells divide until they form new colonies, which are then released. In the smaller forms, typically all cells are involved, but larger forms have anterior vegetative and posterior reproductive cells. Sexual reproduction varies from isogamy (both genders produce flagellated gametes of equal size) to oogamy (one gender produces a much larger, nonmotile gamete).

The classification of the Chlamydomonadales varies. Very often they are taken to include the orders Volvocales and Dunallielales, which contain closely related unicellular flagellates, as suborders. Colony inversion is believed to have arisen twice in this order. Spheroidal colony formation differs between the two lineages: rotation of daughter protoplasts during successive cell divisions in Astrephomene, and inversion after cell divisions in the Volvocaceae. [2]

Schematic representation of the phylogenetic relationships of the volvocine algae and the parallel evolution of the spheroidal colony. Volvocine algae range from the unicellular Chlamydomonas to the multicellular Volvox through various intermediate forms and are used as a model for research into the evolution of multicellularity. The spheroidal colony is thought to have evolved twice independently within this group: once in the Volvocaceae, from Pandorina to Volvox, and the other in the genus Astrephomene. The phylogeny is based on previous reports. All drawings and photographs represent side views of individuals with anterior ends orienting toward the top of this figure. Doi 10.1186-s12862 2016 794 Fig1 HTML.jpg
Schematic representation of the phylogenetic relationships of the volvocine algae and the parallel evolution of the spheroidal colony. Volvocine algae range from the unicellular Chlamydomonas to the multicellular Volvox through various intermediate forms and are used as a model for research into the evolution of multicellularity. The spheroidal colony is thought to have evolved twice independently within this group: once in the Volvocaceae, from Pandorina to Volvox, and the other in the genus Astrephomene. The phylogeny is based on previous reports. All drawings and photographs represent side views of individuals with anterior ends orienting toward the top of this figure.

Families

As of May 2023, AlgaeBase accepted the following families: [3]

Related Research Articles

<span class="mw-page-title-main">Chlorophyceae</span> Class of green algae

The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. They are usually green due to the dominance of pigments chlorophyll a and chlorophyll b. The chloroplast may be discoid, plate-like, reticulate, cup-shaped, spiral- or ribbon-shaped in different species. Most of the members have one or more storage bodies called pyrenoids located in the chloroplast. Pyrenoids contain protein besides starch. Some green algae may store food in the form of oil droplets. They usually have a cell wall made up of an inner layer of cellulose and outer layer of pectose.

<span class="mw-page-title-main">Chlorophyta</span> Phylum of green algae

Chlorophyta is a taxon of green algae informally called chlorophytes. The name is used in two very different senses, so care is needed to determine the use by a particular author. In older classification systems, it is a highly paraphyletic group of all the green algae within the green plants (Viridiplantae) and thus includes about 7,000 species of mostly aquatic photosynthetic eukaryotic organisms. In newer classifications, it is the sister clade of the streptophytes/charophytes. The clade Streptophyta consists of the Charophyta in which the Embryophyta emerged. In this latter sense the Chlorophyta includes only about 4,300 species. About 90% of all known species live in freshwater. Like the land plants, green algae contain chlorophyll a and chlorophyll b and store food as starch in their plastids.

<i>Volvox</i> Genus of algae

Volvox is a polyphyletic genus of chlorophyte green algae in the family Volvocaceae. Volvox species form spherical colonies of up to 50,000 cells, and for this reason they are sometimes called globe algae. They live in a variety of freshwater habitats, and were first reported by Antonie van Leeuwenhoek in 1700. Volvox diverged from unicellular ancestors approximately 200 million years ago.

<span class="mw-page-title-main">Volvocaceae</span> Family of algae

The Volvocaceae are a family of unicellular or colonial biflagellates, including the typical genus Volvox. The family was named by Ehrenberg in 1834, and is known in older classifications as the Volvocidae. All species are colonial and inhabit freshwater environments.

<i>Gonium</i> Genus of algae

Gonium is a genus of colonial algae, a member of the order Chlamydomonadales. Typical colonies have 4 to 16 cells, all the same size, arranged in a flat plate, with no anterior-posterior differentiation. In a colony of 16 cells, four are in the center, and the other 12 are on the four sides, three each. A description by G.M. Smith :

Gonium Mueller 1773: Colonies of 4-8-16 cells arranged in a flat quadrangular plate and embedded in a common gelatinous matrix or connected by broad gelatinous strands. Cells ovoid to pyriform, with a single cup-shaped chloroplast containing one pyrenoid. Each cell with two cilia of equal length, contractile vacuoles at the base of the cilia, and an eyespot. Four- and eight-celled colonies with the cilia on the same side ; sixteen-celled colonies with the four central cells having their cilia on the same side and the twelve marginal cells with radially arranged cilia.

Asexual reproduction by simultaneous division of all cells in the colony to form autocolonies, or by a formation of 2-4 zoospores in each cell.

Sexual reproduction isogamous, by a fusion of biciliatezoogametes.

<span class="mw-page-title-main">Chlamydomonadaceae</span> Family of algae

Chlamydomonadaceae is a family of algae within the order Chlamydomonadales. Traditionally, it has been defined as containing single-celled flagellates with a cell wall.

Oocystaceae is a family of green algae, in the order Chlorellales. The type genus is Oocystis.

<span class="mw-page-title-main">Tetrasporaceae</span> Family of algae

The Tetrasporaceae are a family of green algae, specifically of the Chlamydomonadales. They are found in freshwater habitats.

Astrephomene is a genus of green algae in the family Goniaceae, order Chlamydomonadales. The genus was first described in 1937 by Pocock and named by Pockock in 1953.

<i>Eudorina</i> Genus of algae

Eudorina is a paraphyletic genus in the volvocine green algae clade. Eudorina colonies consist of 16, 32 or 64 individual cells grouped together. Each individual cell contains flagella which allow the colony to move as a whole when the individual cells beat their flagella together. Description by GM Smith :

Asteromonas is a genus of green algae in the family Asteromonadaceae. It has been described from saline, marine, and brackish environments. It is closely related to the genus Dunaliella, another genus common in saline waters.

<i>Carteria</i> Genus of algae

Carteria is a genus of green algae in the family Chlamydomonadaceae. Carteria are similar in morphology to the common genus Chlamydomonas and differ by having four, rather than two, flagella at the vegetative stage.

<i>Chlainomonas</i> Genus of algae

Chlainomonas is a genus of algae in the family Chlamydomonadaceae. They are found in freshwater habitats or on snow, where they are one of the main algae responsible for causing watermelon snow.

<i>Chloromonas</i> Genus of algae

Chloromonas is a genus of green algae in the family Chlamydomonadaceae. It is closely related to the model green algae, Chlamydomonas, and traditionally has been distinguished mainly through the absence of a pyrenoid.

Pectodictyon is a genus of green algae in the family Sphaerodictyaceae. It is found free-floating in freshwater habitats as plankton.

<i>Platydorina</i> Genus of algae

Platydorina is a genus of microscopic green algae in the family Volvocaceae. It contains only one species, Platydorina caudata. It was described by Charles Atwood Kofoid in 1899.

<i>Stephanosphaera</i> Genus of algae

Stephanosphaera is a genus of green algae in the family Haematococcaceae, containing the single species Stephanosphaera pluvialis. It forms colonies of flagellated cells. Although it was once placed in the family Volvocaceae, it is not closely related to them; its sister is the unicellular genus Balticola.

Treubaria is a genus of green algae, the sole genus in the family Treubariaceae. Treubaria is found in freshwater habitats and has a cosmopolitan distribution.

Vitreochlamys is a genus of green algae in the family Chlamydomonadaceae. It is sometimes known by the name Sphaerellopsis, published by Aleksandr Arkadievich Korshikov. However, that name is an illegitimate later homonym, preceded by SphaerellopsisM.C.Cooke. It is commonly found in freshwater habitats.

<span class="mw-page-title-main">Palmellopsidaceae</span> Family of algae

Palmellopsidaceae is a green algae family in the order Chlamydomonadales.

References

  1. ↑ See the NCBI webpage on Chlamydomonadales. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information . Retrieved 2007-03-19.
  2. 1 2 Yamashita S, Arakaki Y, Kawai-Toyooka H, Noga A, Hirono M, Nozaki H (November 2016). "Alternative evolution of a spheroidal colony in volvocine algae: developmental analysis of embryogenesis in Astrephomene (Volvocales, Chlorophyta)". BMC Evol Biol. 16 (1): 243. PMC   5103382 . PMID   27829356. Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
  3. ↑ Guiry, M.D.; Guiry, G.M. "Chlamydomonadales". AlgaeBase . World-wide electronic publication, National University of Ireland, Galway. Retrieved 2023-05-14.
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