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Ehrenberg did not notice Euglena ' s flagella, however. The first to publish a record of this feature was Félix Dujardin, who added "filament flagelliforme" to the descriptive criteria of the genus in 1841. [30] Subsequently, the class Flagellata (Cohn, 1853) was created for creatures, like Euglena, possessing one or more flagella. While ...
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 or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids.
These are often packed together to form two or more rods, which function in ingestion, and in Entosiphon form an extendable siphon. Most phagotrophic euglenids have two flagella, one leading and one trailing. The latter is used for gliding along the substrate. In some, such as Peranema, the leading flagellum is rigid and beats only at its tip.
Flagella are generally used for propulsion. They may also be used to create a current that brings in food. In most such organisms, one or more flagella are located at or near the anterior of the cell (e.g., Euglena). Often there is one directed forwards and one trailing behind.
Euglena gracilis is a freshwater species of single-celled alga in the genus Euglena. It has secondary chloroplasts , and is a mixotroph able to feed by photosynthesis or phagocytosis . It has a highly flexible cell surface, allowing it to change shape from a thin cell up to 100 μm long to a sphere of approximately 20 μm.
Euglenales consists mostly of freshwater organisms, in contrast to its sister Eutreptiales which is generally marine. Cells have two flagella, but only one is emergent; the other is very short and does not emerge from the cell, so cells appear to have only one flagellum. [3]
Some eukaryotic cells, such as the protist Euglena and animal sperm, possess a convergent, evolutionarily distinct [34] flagellum-like structure known as a cilium or undulipodium. Unlike bacterial flagella however, these structures do not rotate at the base; rather, they bend in such a way that the tip whips in a circle. [35]: 1105
The family Euglenaceae is also known by the name Euglenidae. The origin of this dual naming system is because of the history of protists. Euglenids have been treated as both algae and protozoans, which are governed by separate nomenclature codes. [2]