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Volvocales

 

 
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Volvocales
 
 
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In taxonomy
Alpha taxonomy

Alpha taxonomy is the science of finding, describing and categorising organisms, thus leading to the recognition of proposed taxonomic groups, or taxon , which may then be naming conventions....
, the Volvocales are an order
Order (biology)

In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
 of flagellate
Flagellate

Flagellates are cell s with one or more whip-like organelles called flagellum. Some cells in animals may be flagellate, for instance the spermatozoa of most phyla....
 or pseudociliate green algae
Green algae

The green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic ....
, specifically of the Chlorophyceae
Chlorophyceae

The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. For example the chlorophycean CW clade, and chlorophycean DO clade, are defined by the arrangement of their flagella....
. Volvocales can form planar or spherical colonies. These vary from Gonium
Gonium

Gonium is a genus of colonial algae, a member of the order Volvocales. Typical colonies have 4 to 16 cells, all the same size, arranged in a flat plate, with no anterior-posterior differentiation....
 (4 to 32 cells) up to Volvox
Volvox

Volvox is one of the best-known chlorophytes and is the most developed in a series of genera that form spherical colonies. Each mature Volvox colony is composed of numerous flagellate cells similar to Chlamydomonas, up to 50,000 in total, and embedded in the surface of a hollow sphere or coenobium containing an extracellular matr...
 (500 cells or more). Each cell has two flagella, and is similar in appearance to Chlamydomonas
Chlamydomonas

Chlamydomonas is a genus of green alga. They are unicellular flagellates. Chlamydomonas is used as a model organism for molecular biology, especially studies of flagellum motility and chloroplast dynamics, biogenesis, and genetics....
, with the flagella throughout the colony moving in coordination.

Both asexual and sexual reproduction occur.






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In taxonomy
Alpha taxonomy

Alpha taxonomy is the science of finding, describing and categorising organisms, thus leading to the recognition of proposed taxonomic groups, or taxon , which may then be naming conventions....
, the Volvocales are an order
Order (biology)

In Biological classification used in biology, the order is a taxonomic rank between class and family . The superorder is a rank between class and order....
 of flagellate
Flagellate

Flagellates are cell s with one or more whip-like organelles called flagellum. Some cells in animals may be flagellate, for instance the spermatozoa of most phyla....
 or pseudociliate green algae
Green algae

The green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic ....
, specifically of the Chlorophyceae
Chlorophyceae

The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. For example the chlorophycean CW clade, and chlorophycean DO clade, are defined by the arrangement of their flagella....
. Volvocales can form planar or spherical colonies. These vary from Gonium
Gonium

Gonium is a genus of colonial algae, a member of the order Volvocales. Typical colonies have 4 to 16 cells, all the same size, arranged in a flat plate, with no anterior-posterior differentiation....
 (4 to 32 cells) up to Volvox
Volvox

Volvox is one of the best-known chlorophytes and is the most developed in a series of genera that form spherical colonies. Each mature Volvox colony is composed of numerous flagellate cells similar to Chlamydomonas, up to 50,000 in total, and embedded in the surface of a hollow sphere or coenobium containing an extracellular matr...
 (500 cells or more). Each cell has two flagella, and is similar in appearance to Chlamydomonas
Chlamydomonas

Chlamydomonas is a genus of green alga. They are unicellular flagellates. Chlamydomonas is used as a model organism for molecular biology, especially studies of flagellum motility and chloroplast dynamics, biogenesis, and genetics....
, with the flagella throughout the colony moving in coordination.

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
Isogamy

Isogamy refers to a form of sexual reproduction involving gametes of similar morphology, differing only in allele expression in one or more Mating-type region....
 (both genders produce flagellate gamete
Gamete

A gamete is a Cell that fuses with another gamete during fertilization in organisms that sexual reproduction. In species which produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual which produces the larger type of gamete?called an ovum ?and a male produces th...
s of equal size) to oogamy
Oogamy

Oogamy is a form of anisogamy in which the female gamete is significantly larger than the male gamete and is non-motile. The male gametes are typically highly motile spermatozoon competing for the fertilization of the immotile egg....
 (one gender produces a much larger, non-motile gamete).

The classification of the Volvocales varies. Very often they are taken to include the orders Chlamydomonadales
Chlamydomonadales

In alpha taxonomy, the Chlamydomonadales are an order of green algae, specifically the Chlorophyceae....
 and Dunallielales, which contain closely related unicellular flagellates, as suborders.

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