Groups and classes of protista


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Groups and classes of protista

  1. 1. Excavata:Excavata is group of protists that lack the classical mitochondria because of evolution; manyspecialists refer to these mitochondria as an “amitochondriate” even though they retain the samepowers of normal mitochondrias. In addition, the organisms that fall in this phylum contain uniqueflagella. Also, these organisms can have multiple of these unique ck. Moreover, this phylum’sorganisms have “conspicuous ventral feeding grooves”. These grooves are characterized by theirultrastructure that is supported by microtubules. However, not all of the organisms that are labeled inthis phylum contain all of these characterizes but are rather characterized by their genetic evidence.As well, this phylum is made up of organisms that can be multi-cellular or single cellular, but themajority of the organisms are singled celled. Diplomonads: Diplomonads is a class from the phylum Excavata. In this class most of the organisms are parasitic and have flagellas. In addition, most of the organisms in this class have two nuclei with four corresponding flagellas; the flagellas are organized symmetrically around the body’s main axis. Also, these organisms lack mitochondria along with a Golgi apparatus. Yet, this class is known to retain mitosomes, mitochondrial relics. These mitosomes process the job of being involved in the maturation of iron-sulfur proteins rather than ATP synthesis. Euglenozoa: Euglenozoa is another class from the phylum Excavata. This phylum contains a variation of free-living species along with a number of parasites. In addition, euglenozoa are around the size of fifteen to forty µm and unicellular. Most of the euglenozoa encompass two flagella that run parallel to each other and can be found in the apical or subapical pocket. Moreover, these organisms obtain energy through the process of photosynthesis. Therefore, these organisms have the organelle called chloroplast. The pigments that this class uses in photosynthesis are chlorophylls A, C and other pigments. Also, this class reproduces through mitosis. Two of the key characterizations that are used to identify this class normal supporting axoneme, microtubules and the ultrastructure of the flagella.
  2. 2. Chromalveolata:Chromalveolata is a phylum off of the kingdom Protista. Many times these organisms in this phylum aremistaken for plants because they encompass a cell wall along the ability to perform photosynthesis.However, all the organisms in this group have the ability to perform photosynthesis because of evolutionand their ability to adapt. For example, ciliates and water molds have lost their ability to performphotosynthesis. On the other hand, the organisms in this phylum that still use this trait use chlorophylls a,c, along with many other accessory pigments. All Chromalveolates share the trait of glyceraldehyde 3 andphosphate dehydrogenase as their main protein. One of the other common features of this phylumincludes the presence of cellulose in the cell walls. Many of the classes in this phylum are unique thereforemany have declared that this phylum has originated from many different organisms rather than just one.This phylum has been known to affect our ecosystem whether it is for the good or bad. For example,dinoflagellates are produce red tides which are harmful to the fish population and oyster harvests. On theother hand, diatoms are very useful to our ecosystem because they are the major photosyntheticproducers. Alveolates: Alveolates is a class from the phylum of Chromalveolata. The most prominent characteristic that is shared by the organisms in this class is flattened vesicles that support the membrane, cortical alveoli; therefore, this membrane support allows these organisms to arrange a flexible pellicle. Other distinctive characteristics include mitochondria with tubular cristae and cilia or flagella. Another characteristic that is found in these organisms is distinct micropores; these pores have an important function in pinocytosis. Also, this performs closed mitosis. Stramenopiles: Stramenopiles is another class under the Chromalveolata phylum. The organisms in this phylum range dramatically from massive, multicellular kelp to unicellular diatoms. However, there are also parasitic organisms in this class, such as Phytophthora. The main characterization of this class is by flagella shape. Also, these organisms are usually found under the water and preform photosynthesis. With regards to photosynthesis, these organisms possess chloroplasts with four membranes.
  3. 3. Rhizaria:Rhizaria is a phylum that is a part of the kingdom of Protista. Many times these organismshave been mistaken for animals because of their ability to move and the fact that they areheterotrophic. These organisms obtain the characteristics of unicellular and eukaryotic. Also,the main portion of the organisms in this phylum has microtubule-supported pseudopods alongwith the feature of mitochondria with tubular cristae. Rhizarians: Since Rhizarians is the only class under the phylum Rhizaria, the organisms of that phylum automatically go into this class. Therefore, these organisms possess all of the same qualities of the phylum. Archaeplastida: Archaeplastida is a phylum a part of the kingdom Protista. The main organisms that are comprised of this kingdom are red algae and green algae. One of the main characteristics of this phylum is that the plastid is surrounded by two membranes; many specialists suggest that the two membranes come from the evolution of endosymbiotic cyanobacteria. In addition, some other characteristics that make up this phylum are mitochondria with flat cristae, lack of centrioles, a cell wall made up of cellulose, and food that is stored as starch. Also, the classes that make up this phylum are very unique to the phylum because the organisms in this phylum are said to be paraphyletic, evolved from many organisms.
  4. 4. Red Algae: Red Alga is a class in the Archaeplastida phylum. This class is made up of mostly multicellular and found in the sea. Some of the most profound characteristics include neither flagella nor centrioles, starch is used as a food reserve, chloroplast lacking and endoplasmic reticulum, and phycoviliproteins are used as accessory pigments. Also, an interesting fact about this class is that the thylakoids are not stacked. In addition, these organisms reproduce sexually. Green Algae: Green Alga is another example of a class that is under the phylum Archaeplastida. This class includes both unicellular and colonial organisms that have two flagella per cell. The flagellas are fastened by cross-shaped microtubules. Also, these organisms perform the task of photosynthesis to obtain energy. With that being said one can infer that chlorophylls are being used, and the most used chlorophylls for this class is chlorophylls a and b along with many accessory pigments. However, these organisms have stacked thylakoids unlike the class Red Algae. In addition, all of the members of this class have mitochondria including flat cristae. Moreover, this class has cell wall made out of cellulose and experiences the process of mitosis without centrioles.Unikonta:Unikonta is a eukaryotic phylum under the kingdom of Protista. This phylum is closely related tofungi and animals. Most of the organisms in this phylum contain single flagella. Also, this phylumcontains a triple-gene fusion; the triple-gene fusion is important because it encodes enzymesthat have the jobs of synthesizing pyrimidine nucleotides. Another characteristic that is seen inthis phylum includes is a lobe or tube shaped pseudopodia.
  5. 5. Choanoflagellates: Choanoflagellates is a class in the Unikonta phylum. These organisms that make up this class are free-living organisms that have flagella and are either unicellular or able to form a colony. One of the main characteristics of this class is its spherical or ovoid cell body that reaches a diameter of thee to ten µm. Also, the organisms in this class contain one apical flagella enclosed by a collar of microvilli. In addition, these organisms eat by creating water currents with their flagella and trapping bacteria and detritus into its microvilli. Therefore, these organisms are heterotrophic. Another characteristic of these organisms is it contains a food vacuole that is positioned near the basal region.Amoebozoans: Amoebozoans class is another class from the phylum Unikonta. The majority of this class is made up of amoeboid that move by internal cytoplasmic flow. These organisms’ pseudopodia are characterized by their lobopodia. Also, most of these organisms are unicellular but some are multicellular. In addition, these organisms differ in size greatly; this class’ organisms can reach from ten μm to eight hundred μm in length.