Flagellates
The division of living beings into systematics is a continuous subject of research. Different systematic classifications exist side by side and one after the other. The taxon treated here has become obsolete due to new research or is not part of the group systematics presented in the German-language Wikipedia.
Flagellates ( Latin flagellum , whip, scourge) are a group of unicellular , eukaryotic organisms that have whip-like cell processes. The oldest fossil finds come from the Permian (orders Peridiniina and Coccolithophorida).
construction
Flagellates have a single up to thousands of eponymous flagella (flagella) whose primary function is locomotion . They can also serve to whirl around food particles and anchor them to the substrate. The flagellum is a non-actively deformable thread-like protein structure , the point of origin of which is on the cell membrane and can actively rotate. It determines the front end. The protein thread can be moved in a whip-like manner through rotation , which exerts drive thrust or tension on the aqueous medium.
The cells often have two contractile vacuoles (pulsating vesicles) that enlarge rhythmically, absorbing fluid from the cytoplasm and then emptying it outwards. This activity is used for excretion ( diuresis , osmoregulation , excretion of catabolites ). Divisions are made lengthways. In terms of nutrition, morphology and ecology, however, they are extraordinarily diverse.
Classification
The group was described by Karl Moritz Diesing in 1866 as the taxon Mastigophora and was still recognized as such until the end of the 20th century. However, since phylogenetic studies have shown it to be polyphyletic , today it is only understood as an organizational form of single-celled organisms.
Phytoflagellates
The former group of phytoflagellates (Greek φυτόν phyton = (garden) plant, i.e. vegetable) has the common feature of being capable of photosynthesis with the help of chromatophores , e.g. Some of them have the typical vegetable wall building block cellulose and the reserve material starch . Chrysamoeba , Euglena , Volvox and Dinoflagellates were divided into this group .
Zoo flagellates
This former group shared a heterotrophic diet , either through phagocytosis or osmosis, or active membrane transport . They included collar flagellates , trypanosomes , Trichomonas , Trichonympha (now assigned to the Parabasalia / Trichonymphidae ) and Mastigamoebaea (now assigned to the Amoebozoa ).
Individual evidence
- ↑ a b c Rudolf Röttger: Dictionary of Protozoology In: Protozoological Monographs, Vol. 2, 2001, ISBN 3-8265-8599-2 , p. 80.
- ^ Arno Hermann Müller: Textbook of Palaeozoology. Volume II Invertebrates, Part 1. Fischer Verlag, Jena 1980.
- ↑ H. Ettl: Investigations on flagellates. In: Plant Systematics and Evolution , Vol. 112, No. 5, 1966, pp. 701-745.