Euglena

From Wikipedia, the free encyclopedia

Wikipedia:How to read a taxobox
How to read a taxobox
Euglenids

Scientific classification
Domain: Eukaryota
(unranked) Excavata
Phylum: Euglenozoa
Class: Euglenoidea
Order: Euglenales
Family: Euglenaceae
Genus: Euglena
Ehrenberg, 1830

Euglena is a common Euglenophyte protist, typical of the euglenids, and commonly found in nutrient-rich freshwater, with a few marine species. It is considered a Euglenophyte, and not a flagellate, because of the presence of chloroplasts in most species. The cells vary in length from around 20 to 300 μm, and are typically cylindrical, oval, or spindle-shaped with a single emergent flagellum for movement. There are usually many bright green chloroplasts, although some species are colorless. If sunlight is not available, it can absorb nutrients from decayed organic material. Euglena is also found in sewage systems. Euglena reproduces through mitosis, a process in which one cell is divided into two. Euglena has a contractile vacuole which prevents the cell from bursting.

The name comes from the Greek words εὔ (eu) and γλήνη (glēnē), meaning good eyeball, referring to their light-sensitive eyespots, also known as stigmas, used to direct themselves towards light. Over 1000 species of Euglena have been described. Marin et al. (2003) revised the genus so that it forms a monophyletic group, moving several species with rigid pellicles to the genus Lepocinclis and including several species without chloroplasts, formerly classified as Astasia and Khawkinea.

[edit] See also

[edit] References

  • Marin B, Palm A, Klingberg M, Melkonian M (2003). "Phylogeny and taxonomic revision of plastid-containing euglenophytes based on SSU rDNA sequence comparisons and synapomorphic signatures in the SSU rRNA secondary structure." Protist 154(1):99–145.
  • Miller K, Levine J, (2002). "Biology." Euglenophytes page 506

[edit] External links