Eudorina
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''Eudorina'' is a
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...
in the family Volvocaceae, containing about seven species. It has a
cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...
in freshwater habitats.


Description

''Eudorina'' colonies typically consist of 16, 32 or 64 cells, each of which is similar to '' Chlamydomonas reinhardtii''. These cells are bedded within an extracellular matrix composed of glycoproteins. Colonies are spherical and motile, with motility derived from the flagellated individual cells. Cells are ovoid or spherical, each with two equal flagella. (In one species '' Eudorina compacta'', the cells essentially touch each other, and are strikingly angular due to mutual compression.) There is a single cup-shaped
chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...
with one (basal) or multiple
pyrenoid Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''An ...
s) and a stigma. Multiple contractile vacuoles are scattered throughout the cytoplasm. ''Eudorina'' is facultatively sexual, meaning colonies can reproduce either sexually or asexually. During development, each ''Chlamydomonas''-like cell undergoes several rounds of division to form plakeas, which then invert to form daughter colonies before hatching out of the mother colony. Sexual reproduction is
anisogamous Different forms of anisogamy: A) anisogamy of motile cells, B) 283x283px Anisogamy is a form of sexual reproduction">egg cell">oogamy (egg cell and sperm cell), C) anisogamy of non-motile cells (egg cell and spermatia).">283x283px Anisogamy is ...
; cells divide successively and differentiate into sperm packets, or develop into female gametes (without division).


Taxonomy

Although the most common species of ''Eudorina'' (''E. elegans'') is very different from the most common species of '' Pandorina'' (''P. morum''), forms intermediate in morphology between ''Eudorina'' and ''Pandorina'' exist, such as ''Pandorina/Eudorina charkowiensis'' and ''Pandorina unicocca''. These have been reclassified to other genera, namely '' Colemanosphaera'' and '' Yamagishiella'', respectively. In particular, ''Eudorina'' is very similar to ''Yamagishiella'', differing mainly in its mode of reproduction (anisogamous in ''Eudorina'', isogamous in ''Yamagishiella'') and number/placement of contractile vacuoles.
Molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
studies show that ''Eudorina'' is
paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
with respect to '' Pleodorina'' and ''
Volvox ''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. First reported by Antonie van L ...
'' (excluding section ''Volvox''). Taxonomically, ''Eudorina'' has been confused with '' Pleodorina''. In particular, '' Eudorina illinoisensis'' (syn. ''Pleodorina illinoisensis'') blurs the boundaries between the two genera by having four anterior cells which are facultatively somatic. Currently, ''Eudorina'' is distinguished from ''Pleodorina'' by the absence or presence of obligately somatic cells. Phylogenetic relationships are as follows (not all species of ''Eudorina'' are included:


References


External links


Eudorina
- Description with pictures {{Taxonbar, from=Q310125 Chlamydomonadales Chlamydomonadales genera