Euglenids
Scientific classification
Domain: Eukaryota (unranked) Excavata kingdom = protista Image File history File links Euglena_g. ... Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista Alternative Phylogeny Unikonta    Opisthokonta    Amoebozoa Bikonta    Apusozoa    Cabozoa       Rhizaria       Excavata    Corticata       Archaeplastida       Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms with a complex cell or cells, where the genetic material is organized into a membrane-bound nucleus or nuclei. ... This article is about the protist group called excavates. ... Phylum: Euglenozoa Class: Euglenoidea Order: Euglenales Family: Euglenaceae Genus: Euglena Ehrenberg, 1830

Hey 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 an 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. Typical Classes Euglenoidea Kinetoplastea Diplonemea Postgaardea The Euglenozoa are a large group of flagellateprotozoa. ... Major groups Phototrophs    Euglenales    Eutreptiales Osmotrophs    Rhabdomonadales Phagotrophs    ?Heteronematales    ?Sphenomonadales The euglenids (also spelled euglenoids) are one of the best-known groups of flagellates, commonly found in freshwater especially when it is rich in organic materials, with a few marine and endosymbiotic members. ... Christian Gottfried Ehrenberg. ... Typical phyla Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: ) are a diverse group of organisms, comprising those eukaryotes that are not animals... Major groups Phototrophs    Euglenales    Eutreptiales Osmotrophs    Rhabdomonadales Phagotrophs    ?Heteronematales    ?Sphenomonadales The euglenids (also spelled euglenoids) are one of the best-known groups of flagellates, commonly found in freshwater especially when it is rich in organic materials, with a few marine and endosymbiotic members. ... Flagellata from Ernst Haeckels Artforms of Nature, 1904 Parasitic excavate (Giardia lamblia) Green alga (Chlamydomonas) Flagellates are cells with one or more whip-like organelles called flagella. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length. ... // A Flagellum (plural: flagella) is a long, slender projection from the cell body, composed of microtubules and surrounded by the plasma membrane. ... Mitosis divides genetic information during cell division. ... Figure 1: A paramecium. ...

The name comes from the Greek words εὔ (eu) and γλήνη (glēnē), meaning good eyeball, referring to Euglena's stigma (also known as eyespot). Until the discovery of the paraflagellar body it was wrongly believed that this was the organelle responsible for the sensing of light. Instead it is just a part of Euglena's light receptive system and its role is to shield light from the actual light sensitive paraflagellar body (PFB) or so-called photoreceptor. Orientation of the organism towards light is called Phototaxis. Schematic representation of a Euglena cell with red eyespot (9) Schematic representation of a Chlamydomonas cell with chloroplast eyespot (4) The eyespot apparatus (or stigma) is a photoreceptive organelle found in the flagellate (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids. ... Schematic representation of a Euglena cell with red eyespot (9) Schematic representation of a Chlamydomonas cell with chloroplast eyespot (4) The eyespot apparatus (or stigma) is a photoreceptive organelle found in the flagellate (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids. ... Phototaxis is an organisms automatic movement toward or away from 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. In phylogenetics, a group is monophyletic (Greek: of one stem) if all organisms in that group are known to have developed from a common ancestral form, and all descendants of that form are included in the group. ...

See also

• Euglenids

Major groups Phototrophs    Euglenales    Eutreptiales Osmotrophs    Rhabdomonadales Phagotrophs    ?Heteronematales    ?Sphenomonadales The euglenids (also spelled euglenoids) are one of the best-known groups of flagellates, commonly found in freshwater especially when it is rich in organic materials, with a few marine and endosymbiotic members. ...

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. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Retrieve&list_uids=12812373
• Miller K, Levine J, (2002). "Biology." Euglenophytes page 506

External links

• Euglena
• Protist Images: Euglena
• Euglena at Droplet - Microscopy of the Protozoa
• Images and taxonomy
• Pictures of Euglena gracilis
• Effect of Light Intensity on the Lipid Composition of Euglena gracilis
• Mitochondrial trans-2-Enoyl-CoA Reductase of Wax Ester Fermentation from Euglena gracilis Defines a New Family of Enzymes Involved in Lipid Synthesis
• Aliphatic Chains of Esterified Lipids in Isolated eyesptos of Euglena gracilis var. bacillaris1 (pdf)
• Nature, intracellular distribution and formation of terpenoid quinones in Euglena gracilis. (pdf)
• Tryptophan Synthetase in Euglena gracilis Strain G (pdf)
• Lipid Metabolism of Manganese-deficient Algae: I. Effect of Manganese Deficiency on the Greening and the Lipid Composition of Euglena Gracilis Z. (pdf)
• A hydroxy fatty acid dehydrogenase in Euglena gracilis (pdf)
• Comparative studies of biosynthesis of galactolipids in Euglena gracilis strain Z (pdf)
• The Euglena Project