Protozoa Definition and Classification PDF

Definition 6. Body naked or bounded by a pellicle and often Protozoa may be defined as microscopic and provided with simple to elaborate shells acellular animalcules, without tissues and organs, exoskeletons....

Definition 6. Body naked or bounded by a pellicle and often Protozoa may be defined as microscopic and provided with simple to elaborate shells acellular animalcules, without tissues and organs, exoskeletons. having one or more nuclei, but no nucleus ever 7. Body form usually constant, varied in some, incharge of specialized part of cytoplasm. while changing with environment or age in They exist either single or in colonies which many. differ from metazoan in having all the 8. The single cell body performs all the essential individuals alike except when engaged in and vital activitics, which characterize the reproductive activities. animal body; hence only subcellular General Characters physiological division of labou. 9. Locomotor organelles finger-like are usually microscopic animalcules, 1. Small, pseudopodia or whip-like flagella or hairlike ordinarily not visible without a microscope. cilia or absent. 2. Simplest and most primitive of all animals, 10. Nutrition holozoic (animal-like), holophytic with protoplasmic grade of organization. (plant-like), saprozoic or pcrasitic. With or 3. Body unicellular, containing one or more without definitc oral and anal apertures. nucleiwhich are monomorphic or dimorphic. Digestion occurs intraccllularly inside food 4. Solitary or forming loose colonies in which vacuoles. individuals remain alike and independent. 11. Respiration and excretion through general D. Body symmetry none, bilateral, radial or surface or through contractile vacuoles, which spherical. serve mainly for osmore,ulation.  Society of Protozoologists, and mainly proposed 12 Reproduction asena by binary or multiple fission and budding, and seual by by B.M. Hoaigberg and others (1964). It divides Protozoa first into 4 subphyla : (1) Sarcoma. conjugation of adults (hologamy) or by fusion of gametes (syngamy). stigophora, (2) Sporozoa, (3) Cridospora, and 13. Life history often complicated with (4) Ciliophora. Only important orders haye been alternation of asenual and sexual phases. mentioned here. 14. Encystment commonly occurs to help in dispersal as well as to resist unfavourable SUBPHYLUM I. SARCOMASTIGOPHORA conditions of food, temperature and moisture. Locomotor organelles pseudopodia or fagella or both. Nuclei of one kind (monomorphic). 15. Free-iving Protozoa mostly aquatic, inhabiting fresh and sea waters and damp places. Superclass A. Mastigophora (=Flagellata) Parasitic and commensa Protozoa live over or 1. Simple, primitive, with firm pellicle. inside the bodies of animals and plants. 2. Locomotor organelles flagella. moisture is essential in their Sufficient 3. Nutrition autotrophic or heterotrophic, or environment. both. 16. The single-celled individual not differentiated into somatoplasm and germplasm; therefore, Class 1. Phytomastigophorea (=Phytoflagellata) cxempt from the natural death which is 1. Chlorophyll-bcaring chromatophores present. pricc paid for the body. 2. Nutrition mainly holophytic by phototrophy. 17. About 50,000 known species. 3. Reserve food starch or paramylon. 4. Flagella 1 or 2, somnetimes more. Classification Order 1. Chrysomonadida Phylum Protazoa is a large and varied group and 1. Small with thin pellicle, often amoeboid. poses a number of problems in its classification. The Flagella 1 to 3. conventional scheme followed by Hyman (1940), 2. Gullet absent. Stigma often present. Hickman (1961) and Storer (1965) etc. recognizes 2 3. Chromatophores 1 or 2, yellow or brown, subpbyla on the basis of organs of locomotion and 5 and discoidal. 4. Starch absent. Leucosin and fats may be classes, briefly outlinedas follows: present. Subphyium A. Plasmodroma Examples Chrysamoeba, Synura, Locomotory organelles are flagella, pseudopodia, or none. Ochromonas, Dinobryon. Nuclei of one kind. Class L. Mastigophora Move by one to many flagella. Ex. Order 2. Cryptomonadida Euglena 1. Small, with a rigid pellicle. Flagella 2. Class 2 Sarcodina Move and capture lood by pseudopodia. 2. Anterior gullet reaches up to middle of EL Amocba Clss 3. Sporozoa. No locomotory organs. All parasitic. Spore body. formation common. Ex. Plasnodiun 3. Chromatophores 2, yellow, brown or colourless. Subphylum B. Ciliophora 4. Reserve foodstuff starch, sometimes oils. Cilia or sucking tentacies throughout or at certain stages. Examples :Chilomonas, Cryptomonas. Nuclei of 2 kinds. Class 4. Cilisla Move by cilia throughout life. Order 3. Euglenida Ex. Paramecium 1. Large, pellicle thick and firm. Flagella Class 5. Suctoria Move by cilia as young and by tentacles as 1or 2. adult. Ex. Podophyra The following classification of Protozoa is 2. Anterior end with a gullet leading into a reservoir. based on the schcme given by the Committee on 3. Chromatophores numerous, grecn Taxonomy and Taxonomic Problems of the colourless. 4 Reserve foodstuff paramylon and oils. 2. Flagella 3 to 8. One often trailing or forming Examples Euglena, Peranema, Phacus, border of an undulating membrane. Copromonas. 3. Mostly intestinal parasites. Order 4. Volvocida Examples : Hexamita, Giardia. (=Phytomonadida) 1. Small, with rigid cellulose covering (theca). Order 5. Hypermastigida 2. No gullet. Flagella 2 to 4. 1. Highly specialized, numerous lagella. 3. Chromatophore green, usually cup-shaped. 2. Kinetosomes arranged in a circle, plate or 4. Reserve foodstuff starch and oils. longitudinal or spiral rows. Examples : Chlamydomonas, Volvax. 3. Mouth absent. Food ingested by Order 5. Chloromonadida pseudopodia. 4. Gut parasites of termites and cockroaches. 1. Small, dorso-ventrally flat. Pellicle delicate. 2. Gullet present. Examples : Lophomonas, Trychonympha. 3. Chromatophores green and numerous. Order 6. Trichomonadida 4. Reserve foodstuff oils. 1. Flagella4 to 6. One flagellum trailing. Examples Vacularia, Coelomonas, 2. Parasites of vertebrates. Gonyostomum. Example :Trichomonas. Order 6. Dinoflagellida Superclass B. Opalinata 1. Small, planktonic. Naked, amoeboid or with 1. Entire body covered by cilia-like lagella. a thick cellulose theca. 2. Nuclei 2 to many, monomorphic. 2. Gullet present or absent. Flagella 2. 3. Reproduction by synmetrogenic binary 3. Chromatophores yellow or brown. fission or by syngamy of anisogametes. 4, Reserve foodstuff starch or oils or both. 4. Parasitic mainly in frogs and toads. 5. Some are bioluminescent. Examples: Opalina, Zelleriella. Examples: Noctiluca, Ceratium. Superclass C. Sarcodina (=Rhizopoda) Class 2. Zoomastigopohrea (=Zooflagellata) 1. Chlorophyll or chromatophores absent. 1. Body mostly amocboid without definite Mostly parasitic. pellicle. Some with a skeleton of some kind. 2. Nutrition holozoic or saprozoic. 2. Locomotion by pseudopodia. 3. Reserve food glycogen. 3. Nutrition holozoic or saprozoic. 4. Flagella one to many. Class 1. Rhizopodea Order 1. Rhizomastigida Pseudopodia as lobopodia, filopodia or 1. Small, amoeboid, chiefly freshwater. reticulopodia, without axial filaments. 2. Locomotion by 1-4 flagella and pscudopodia. Subclass (a) Lobosia Examples : Mastigamoeba, Dimorpha. Pseudopodia as lobopodia. Order 2. Kinetoplastida Order 1. Amoebida 1. No gullet. Kinetoplast present. 1. Body amoeboid, naked, without skeleton. 2. Flagella 1 to 4. No definite pellicle. 2. Nucleus with honeycomb lattice. 3. Mostly parasitic forms living in blood. 3. Largely freshwater and free-living. Many Examples: Bodo, Leishmania, Trypanosoma. parasitic. Order 3. Choanoflagellida Examples :Amoeba, Entamoeba, Pelomyza. 1. A collar round the base of a single flagellum. Order 2. Arcellinida (=Testacida) 2. Free-living, solitary or colonial. 1. Body enclosed in onc-chambered shell of Example : Proterospongia. pscudochitin, with a single opening through Order 4. Diplomonadida which lobopodia protrude. 1. Bilaterally symmetrical, binuclcate, with 2. Frce-living, mostly freshwater. Examples :Arcella, Difflugia, Euglypha. delicate pellicle and cften with a cytostomc. Subclass (b) Filosia SUBPHYLUM II. SPOROZOA Pseudopodia as filopodia. Naked or with a shell Locomotor organelles absent. Spores usually with singie aperturc. present. Exclusively endoparasites. Examples : Allogronia, Penardia (naked). Class 1. Telosporea Subclass (c) Granuloreticulosia Spores without polar capsules and filaments. Pseudopodia delicate granular reticulopodia. naked or encysted. Order Foraminiferida or multichambered Subclass (a) Gregarinia Large sized with uni 1 Mature trophozoites large, extracellular in calcarcous shell with one or more openings host's gut and body cavities. through which reticulopodia emerge. 2. Each spore produces 8 sporozoites. Examples Globigerin, Elphidium Parasites in invertebrates. 3. (=Polystomella) Examples : Monocystis, Gregarina. Class 2. Actinopodea Subclass (b) Coccidia /APICOMPLEXA Pscudopodia mainly axopodia with axial 1. Mature trophozoites small and intracellular. filaments, radiating from a spherical body. · 2. Each oocyst produces many sporozoites. Subclass (a) Heliozoia sun-animalcules. 3. Blood or gut parasites of vertebrates. 1. Sphcrical protozoans, called Examples : Eimeria, Isospora, Plasmodium. 2. Pseudopodia (axopodia) radiating. siliceous scales or Class 2. Toxoplasmea 3. Naked or skeleton of spines. Spores absent. Only asexual reproduction. Examples :Actinophrys, Actinosphaeriun. Example : Toxoplasma. Subclass (6) Radiolaria Class 3. Haplosporea perforated chitinoid Spore cases present. Only asexual reproduction. 1. Body naked or with central capsule separating ectoplasm from Example : Ichthyosporidium. cndoplasm. SUBPHYLUM III. CNIDOSPORA 2. Reticulopodia, axopodia or filopodia. 3. Skelcton mostly of siliceous spicules or of Spores with polar filaments present. strontium sulphate. Examples : Collozounn, Thalassicola. Class 1. Myxosporidea Subclass (c)Acantharia 1. Spores large, developed from several nuclei. 2. Spores with two or three valves. 1. Imperforate non-chitinoid ccntral capsule 3. Parasites mostly in fishes. without pores. Examples Myxidium, Myzobol1s, 2. Skeleton of strontium sulphatc. Ceratomyxa. 3. Pscudopodia are axopodia. Example : Acanthometra. Class 2. Microsporidea Subclass (d) Proteomyridia 1. Spores small, developed from one nucleus. 1. Pseudopodia are filopodia. 2. Spores with a univalved membrane. 2. Mostly parasites on algae. 3. Intracellular parasites in arthropods and fishes. Example : Nosema. Examples : Vampyrella, Pseudospora. SUBPHYLUM IV. CILIOPHORA Class 3. Piroplasmea feeding Small parasites in red blood cclls of vertcbrates. Presence of cilia as locomotor and Examplc: Babesia (íormerly included with organelles at some stage in the life cycle. Nuciel Sporozoa, but its species do not produce sporcs). of 2 kinds (dimorphic).  Class Ciliata (=Infusoria) Subclass (d) Spirotrichia 1 Locomotor organelles numerous hair-like cilia, 1 Rcduced body cilia. present throughout life. 2 Buccal cilia well marked. 2 Definite mouth (cytostome) and gullet present Order 1. Heterotrichida except in a few parasitic forms. Anal aperture (cytopyge) permancnt. Body cilia short. Uniform or absent. 3 One or more contractile vacuoles present even Examples : Stentor, Bursaria, Spirostomum. in marinc and parasitic types. Order 2. Oligotrichida 4. Mostly two kinds of nuclei, large macronucleus Body cilia reduced or absent. Buccal and smaller micronucleus. membranes conspicuous. Subclass (a) Holotricha Examples: Strombidiun, Halterna. 1. Body cilia simple and uniform. Order 3. Hypotrichida 2. Buccal cilia mostly absent. Dorso-ventrally flattcned. Fused cilia forming ventral cirri. Order 1. Gymnostomatida Large ciliates without oral ciliature. Cytostome Examples: Euplotes, Stylonchia. opens directly. No vestibule. Other Types of Protozoa Examples Coleps, Didinium, Prorodon, Dileptus. 1. Chlamydomonas. Chlamydomonas is a typical the order Phytomonadida. Thc genus of Order 2. Trichostomatida microscopic, uniccllular and solitary individuals With vestibular but no buccal ciliature. Examples : Balantidium, CoBpoda. are found in stagnant freshwater ponds. Ovoid or flattencd body is surrounded by a thick and Order 3. Chonotrichida delicate celhulose cell wall or capsule. It bcars No body ciliature. A spirally coiled apical two long flagella, cach arising from funnel contains vestibular cilia. blepharoplast in cytoplasm. The cytoplasm Examples: Spirochona, Lobochona. includes vesicular nucleus, a cup-shapcd Order 4. Apostomatida chloroplast, with a pyrenoid, a rcd stigma, a pair of small contractile vacuoles and reservc food Spirally arranged body cilia. Cytostome midventral. granules as starch and oil droplcts. Nutrition is Example : Hyalophysa. mainly holophytic but osmotrophic tendency is also seen. Asexual rcproduction is by binary Order 5. Astomatida fission, often in palmella stage. Sexual Body ciliation uniform. Cytostome absent. Example : Anoplophyrya, Maupasella. Order 6. Hymenostomatida contractile vacuole, flagellum Body ciliation uniform. Buccal cavity ventral with ciliary membranes. stigma kinetosome or Examples : Colpidium, Paramecium. cell membrane blepharoplast Subclass (b) Peritricha cellulose nucleus 1. Adult without body cilia. cell wall 2. Apical end with buccal cilia. reserve Order: Peritrichida chloroplast food granules Examples : Voricella, Carchesiunm. Subclass (c) Suctoria Pyrenoid cytloplasm 1. Sessile and stalked body. 2. Young with cilia, adult with suctorial tentacles. starch grains Order: Suctorida Examples : Acineta, Ephelota, Podophyra. lig. 1. Chlamydomonas