Protozoa - wikipedia Protozoa Diverse motile unicellular heterotrophic eukaryotic organisms Clockwise from top left : Blepharisma japonicum, a ciliate ; Giardia muris, a parasitic flagellate ; Centropyxis aculeata, a testate ( shelled ) amoeba ; Peridinium willei, a dinoflagellate ; Chaos carolinense, a naked amoebozoan ; Desmerella moniliformis, a choanoflagellate Protozoa ( also protozoan, plural protozoans ) is an informal term for single - celled eukaryotes, either free - living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris. Historically, the protozoa were regarded as `` one - celled animals '', because they often possess animal - like behaviors, such as motility and predation, and lack a cell wall, as found in plants and many algae. Although the traditional practice of grouping protozoa with animals is no longer considered valid, the term continues to be used in a loose way to identify single - celled organisms that can move independently and feed by heterotrophy. In some systems of biological classification, Protozoa is a high - level taxonomic group. When first introduced in 1818, Protozoa was erected as a taxonomic class, but in later classification schemes it was elevated to a variety of higher ranks, including phylum, subkingdom and kingdom. In a series of classifications proposed by Thomas Cavalier - Smith and his collaborators since 1981, Protozoa has been ranked as a kingdom. The seven - kingdom scheme presented by Ruggiero et al. in 2015, places eight phyla under Kingdom Protozoa : Euglenozoa, Amoebozoa, Metamonada, Choanozoa sensu Cavalier - Smith, Loukozoa, Percolozoa, Microsporidia and Sulcozoa. Notably, this kingdom excludes several major groups of organisms traditionally placed among the protozoa, including the ciliates, dinoflagellates, foraminifera, and the parasitic apicomplexans, all of which are classified under Kingdom Chromista. Kingdom Protozoa, as defined in this scheme, does not form a natural group or clade, but a paraphyletic group or evolutionary grade, within which the members of Fungi, Animalia and Chromista are thought to have evolved. Contents 1 History 2 Characteristics 2.1 Size 2.2 Habitat 2.3 Feeding 2.4 Motility 2.5 Pellicle 2.6 Life cycle 3 Classification 4 Ecology 4.1 Disease 5 References 6 Bibliography 7 External links History upright = 1.35 Class Protozoa, order Infusoria, family Monades by Georg August Goldfuss, c. 1844 The word `` protozoa '' ( singular protozoon or protozoan ) was coined in 1818 by zoologist Georg August Goldfuss, as the Greek equivalent of the German Urthiere, meaning `` primitive, or original animals '' ( ur - ' proto - ' + Thier ' animal ' ). Goldfuss created Protozoa as a class containing what he believed to be the simplest animals. Originally, the group included not only single - celled microorganisms but also some `` lower '' multicellular animals, such as rotifers, corals, sponges, jellyfish, bryozoa and polychaete worms. The term Protozoa is formed from the Greek words πρῶτος ( prôtos ), meaning `` first '', and ζῶα ( zôa ), plural of ζῶον ( zôon ), meaning `` animal ''. The use of Protozoa as a formal taxon has been discouraged by some researchers, mainly because the term implies kinship with animals ( Metazoa ) and promotes an arbitrary separation of `` animal - like '' from `` plant - like '' organisms. In 1848, as a result of advancements in cell theory pioneered by Theodor Schwann and Matthias Schleiden, the anatomist and zoologist C.T. von Siebold proposed that the bodies of protozoans such as ciliates and amoebae were made up of single cells, similar to those from which the multicellular tissues of plants and animals were constructed. Von Siebold redefined Protozoa to include only such unicellular forms, to the exclusion of all metazoa ( animals ). At the same time, he raised the group to the level of a phylum containing two broad classes of microorganisms : Infusoria ( mostly ciliates and flagellated algae ), and Rhizopoda ( amoeboid organisms ). The definition of Protozoa as a phylum or sub-kingdom made up of `` unicellular animals '' was adopted by the zoologist Otto Bütschli -- celebrated at his centenary as the `` architect of protozoology '' -- and the term came into wide use. John Hogg 's illustration of the Four Kingdoms of Nature, showing `` Primigenal '' as a greenish haze at the base of the Animals and Plants, 1860 As a phylum under Animalia, the Protozoa were firmly rooted in the old `` two - kingdom '' classification of life, according to which all living beings were classified as either animals or plants. As long as this scheme remained dominant, the protozoa were understood to be animals and studied in departments of Zoology, while photosynthetic microorganisms and microscopic fungi -- the so - called Protophyta -- were assigned to the Plants, and studied in departments of Botany. Criticism of this system began in the latter half of the 19th century, with the realization that many organisms met the criteria for inclusion among both plants and animals. For example, the algae Euglena and Dinobryon have chloroplasts for photosynthesis, but can also feed on organic matter and are motile. In 1860, John Hogg argued against the use of `` protozoa '', on the grounds that `` naturalists are divided in opinion -- and probably some will ever continue so -- whether many of these organisms, or living beings, are animals or plants. '' As an alternative, he proposed a new kingdom called Primigenum, consisting of both the protozoa and unicellular algae ( protophyta ), which he combined together under the name `` Protoctista ''. In Hoggs 's conception, the animal and plant kingdoms were likened to two great `` pyramids '' blending at their bases in the Kingdom Primigenum. Six years later, Ernst Haeckel also proposed a third kingdom of life, which he named Protista. At first, Haeckel included a few multicellular organisms in this kingdom, but in later work he restricted the Protista to single - celled organisms, or simple colonies whose individual cells are not differentiated into different kinds of tissues. Despite these proposals, Protozoa emerged as the preferred taxonomic placement for heterotrophic microorganisms such as amoebae and ciliates, and remained so for more than a century. In the course of the 20th century, however, the old `` two kingdom '' system began to weaken, with the growing awareness that fungi did not belong among the plants, and that most of the unicellular protozoa were no more closely related to the animals than they were to the plants. By mid-century, some biologists, such as Herbert Copeland, Robert H. Whittaker and Lynn Margulis, advocated the revival of Haeckel 's Protista or Hogg 's Protoctista as a kingdom - level eukaryotic group, alongside Plants, Animals and Fungi. A variety of multi-kingdom systems were proposed, and Kingdoms Protista and Protoctista became well established in biology texts and curricula. While many taxonomists have abandoned Protozoa as a high - level group, Thomas Cavalier - Smith has retained it as a kingdom in the various classifications he has proposed. As of 2015, Cavalier - Smith 's Protozoa excludes several major groups of organisms traditionally placed among the protozoa, including the ciliates, dinoflagellates and foraminifera ( all members of the SAR supergroup ). In its current form, his kingdom Protozoa is a paraphyletic group which includes a common ancestor and most of its descendants, but excludes two important clades that branch within it : the animals and fungi. Since the protozoa, as traditionally defined, can no longer be regarded as `` primitive animals '' the terms `` protists '', `` Protista '' or `` Protoctista '' are sometimes preferred. In 2005, members of the Society of Protozoologists voted to change its name to the International Society of Protistologists. Characteristics Size Protozoa, as traditionally defined, range in size from as little as 1 micrometre to several millimetres, or more. Among the largest are the deep - sea -- dwelling xenophyophores, single - celled foraminifera whose shells can reach 20 cm in diameter. The ciliate Spirostomum ambiguum can attain 3 mm in length Species Cell type Size in micrometres Plasmodium falciparum malaria parasite, trophozoite phase 1 - 2 Massisteria voersi free - living cercozoan amoeboid 2.3 -- 3 Bodo saltans free living kinetoplastid flagellate 5 - 8 Plasmodium falciparum malaria parasite, gametocyte phase ) 7 - 14 Trypanosoma cruzi parasitic kinetoplastid, Chagas disease 14 - 24 Entamoeba histolytica parasitic amoebozoan 15 -- 60 Balantidium coli parasitic ciliate 50 - 100 Paramecium caudatum free - living ciliate 120 - 330 Amoeba proteus free - living amoebozoan 220 -- 760 Noctiluca scintillans free - living dinoflagellate 700 -- 2000 Syringammina fragilissima foraminiferan amoeboid up to 7005200000000000000 ♠ 200 000 Habitat Free - living protozoans are common and often abundant in fresh, brackish and salt water, as well as other moist environments, such as soils and mosses. Some species thrive in extreme environments such as hot springs and hypersaline lakes and lagoons. All protozoa require a moist habitat ; however, some can survive for long periods of time in dry environments, by forming resting cysts which enable them to remain dormant until conditions improve. Parasitic and symbiotic protozoa live on or within other organisms, including vertebrates and invertebrates, as well as plants and other single - celled organisms. Some are harmless or beneficial to their host organisms ; others may be significant causes of diseases, such as babesia, malaria and toxoplasmosis. Isotricha intestinalis, a ciliate present in the rumen of sheep. Association between protozoan symbionts and their host organisms can be mutually beneficial. Flagellated protozoans such as Trichonympha and Pyrsonympha inhabit the guts of termites, where they enable their insect host to digest wood by helping to break down complex sugars into smaller, more easily digested molecules. A wide range of protozoans live commensally in the rumens of ruminant animals, such as cattle and sheep. These include flagellates, such as Trichomonas, and ciliated protozoa, such as Isotricha and Entodinium. The ciliate subclass Astomatia is made up entirely of mouthless symbionts adapted for life in the guts of annelid worms. Feeding All protozoans are heterotrophic, deriving nutrients from other organisms, either by ingesting them whole or consuming their organic remains and waste - products. Some protozoans take in food by phagocytosis, engulfing organic particles with pseudopodia ( as amoebae do ), or taking in food through a specialized mouth - like aperture called a cytostome. Others take in food by osmotrophy, absorbing dissolved nutrients through their cell membranes. Parasitic protozoans use a wide variety of feeding strategies, and some may change methods of feeding in different phases of their life cycle. For instance, the malaria parasite Plasmodium feeds by pinocytosis during its immature trophozoite stage of life ( ring phase ), but develops a dedicated feeding organelle ( cytostome ) as it matures within a host 's red blood cell. Paramecium bursaria, a ciliate which derives some of its nutrients from algal endosymbionts in the genus Chlorella Protozoa may also live as mixotrophs, supplementing a heterotrophic diet with some form of autotrophy. Some protozoa form close associations with symbiotic photosynthetic algae, which live and grow within the membranes of the larger cell and provide nutrients to the host. Others practice kleptoplasty, stealing chloroplasts from prey organisms and maintaining them within their own cell bodies as they continue to produce nutrients through photosynthesis. The ciliate Mesodinium rubrum retains functioning plastids from the cryptophyte algae on which it feeds, using them to nourish themselves by autotrophy. These, in turn, may be passed along to dinoflagellates of the genus Dinophysis, which prey on Mesodinium rubrum but keep the enslaved plastids for themselves. Within Dinophysis, these plastids can continue to function for months. Motility Organisms traditionally classified as protozoa are abundant in aqueous environments and soil, occupying a range of trophic levels. The group includes flagellates ( which move with the help of whip - like structures called flagella ), ciliates ( which move by using hair - like structures called cilia ) and amoebae ( which move by the use of foot - like structures called pseudopodia ). Some protozoa are sessile, and do not move at all. Pellicle Unlike plants, fungi and most types of algae, protozoans do not typically have a rigid cell wall, but are usually enveloped by elastic structures of membranes that permit movement of the cell. In some protozoans, such as the ciliates and euglenozoans, the cell is supported by a composite membranous envelope called the `` pellicle. '' The pellicle gives some shape to the cell, especially during locomotion. Pellicles of protozoan organisms vary from flexible and elastic to fairly rigid. In ciliates and Apicomplexa, the pellicle is supported by closely packed vesicles called alveoli. In euglenids, it is formed from protein strips arranged spirally along the length of the body. Familiar examples of protists with a pellicle are the euglenoids and the ciliate Paramecium. In some protozoa, the pellicle hosts epibiotic bacteria that adhere to the surface by their fimbriae ( attachment pili ). Resting cyst of ciliated protozoan Dileptus viridis. Life cycle Life cycle of parasitic protozoan, Toxoplasma gondii Some protozoa have two - phase life cycles, alternating between proliferative stages ( e.g., trophozoites ) and dormant cysts. As cysts, protozoa can survive harsh conditions, such as exposure to extreme temperatures or harmful chemicals, or long periods without access to nutrients, water, or oxygen for periods of time. Being a cyst enables parasitic species to survive outside of a host, and allows their transmission from one host to another. When protozoa are in the form of trophozoites ( Greek tropho = to nourish ), they actively feed. The conversion of a trophozoite to cyst form is known as encystation, while the process of transforming back into a trophozoite is known as excystation. All protozoans reproduce asexually by binary fission or multiple fission. Many protozoan species exchange genetic material by sexual means ( typically, through conjugation ) ; however, sexuality is generally decoupled from the process of reproduction, and does not immediately result in increased population. Although meiotic sex is widespread among present day eukaryotes, it has, until recently, been unclear whether or not eukaryotes were sexual early in their evolution. Due to recent advances in gene detection and other techniques, evidence has been found for some form of meiotic sex in an increasing number of protozoans of ancient lineage that diverged early in eukaryotic evolution. ( See eukaryote reproduction. ) Thus, such findings suggest that meiotic sex arose early in eukaryotic evolution. Examples of protozoan meiotic sexuality are described in the articles Amoebozoa, Giardia lamblia, Leishmania, Plasmodium falciparum biology, Paramecium, Toxoplasma gondii, Trichomonas vaginalis and Trypanosoma brucei. Classification Further information : wikispecies : Protozoa Historically, the Protozoa were classified as `` unicellular animals '', as distinct from the Protophyta, single - celled photosynthetic organisms ( algae ) which were considered primitive plants. Both groups were commonly given the rank of phylum, under the kingdom Protista. In older systems of classification, the phylum Protozoa was commonly divided into several sub-groups, reflecting the means of locomotion : Classification schemes differed, but throughout much of the 20th century the major groups of Protozoa included : Flagellates, or Mastigophora ( motile cells equipped with whiplike organelles of locomotion, e.g., Giardia lamblia ) Amoebae or Sarcodina ( cells that move by extending pseudopodia or lamellipodia, e.g., Entamoeba histolytica ) Sporozoans, or Sporozoa ( parasitic, spore - producing cells, whose adult form lacks organs of motility, e.g., Plasmodium knowlesi ) Apicomplexa ( now in Alveolata ) Microsporidia ( now in Fungi ) Ascetosporea ( now in Rhizaria ) Myxosporidia ( now in Cnidaria ) Ciliates, or Ciliophora ( cells equipped with large numbers of short hairlike organs of locomotion, e.g., Balantidium coli With the emergence of molecular phylogenetics and tools enabling researchers to directly compare the DNA of different organisms, it became evident that, of the main sub-groups of Protozoa, only the ciliates ( Ciliophora ) formed a natural group, or monophyletic clade ( that is, a distinct lineage of organisms sharing common ancestry ). The other classes or subphyla of Protozoa were all polyphyletic groups made up of organisms that, despite similarities of appearance or way of life, were not necessarily closely related to one another. In the system of eukaryote classification currently endorsed by the International Society of Protistologists, members of the old phylum Protozoa have been distributed among a variety of supergroups. Ecology As components of the micro - and meiofauna, protozoa are an important food source for microinvertebrates. Thus, the ecological role of protozoa in the transfer of bacterial and algal production to successive trophic levels is important. As predators, they prey upon unicellular or filamentous algae, bacteria, and microfungi. Protozoan species include both herbivores and consumers in the decomposer link of the food chain. They also control bacteria populations and biomass to some extent. Disease Trophozoites of the amoebic dysentery pathogen Entamoeba histolytica with ingested human red blood cells ( dark circles ) Main article : Protozoan infection A number of protozoan pathogens are human parasites, causing diseases such as malaria ( by Plasmodium ), amoebiasis, giardiasis, toxoplasmosis, cryptosporidiosis, trichomoniasis, Chagas disease, leishmaniasis, African trypanosomiasis ( sleeping sickness ), amoebic dysentery, acanthamoeba keratitis, and primary amoebic meningoencephalitis ( naegleriasis ). The protozoan Ophryocystis elektroscirrha is a parasite of butterfly larvae, passed from female to caterpillar. Severely infected individuals are weak, unable to expand their wings, or unable to eclose, and have shortened lifespans, but parasite levels vary in populations. Infection creates a culling effect, whereby infected migrating animals are less likely to complete the migration. This results in populations with lower parasite loads at the end of the migration. This is not the case in laboratory or commercial rearing, where after a few generations, all individuals can be infected. References Jump up ^ Panno, Joseph ( 14 May 2014 ). The Cell : Evolution of the First Organism. Infobase Publishing. ISBN 9780816067367. Jump up ^ Bertrand, Jean - Claude ; Caumette, Pierre ; Lebaron, Philippe ; Matheron, Robert ; Normand, Philippe ; Sime - Ngando, Télesphore ( 2015 - 01 - 26 ). Environmental Microbiology : Fundamentals and Applications : Microbial Ecology. Springer. ISBN 9789401791182. Jump up ^ Madigan, Michael T. ( 2012 ). Brock Biology of Microorganisms. Benjamin Cummings. ISBN 9780321649638. Jump up ^ Yaeger, Robert G. ( 1996 ). `` Protozoa : Structure, Classification, Growth, and Development ''. NCBI. Retrieved 2018 - 03 - 23. ^ Jump up to : Goldfuss, Georg August ( 1820 ). Handbuch der Zoologie. Nuremberg : J.L. Schrag. pp. 11 -- 16. Jump up ^ Cavalier - Smith, Thomas ( 1981 ). `` Eukaryote kingdoms : seven or nine ? ''. Bio Systems. 14 ( 3 -- 4 ) : 461 -- 481. doi : 10.1016 / 0303 - 2647 ( 81 ) 90050 - 2. PMID 7337818. Jump up ^ Cavalier - Smith, Thomas ( December 1993 ). `` Kingdom protozoa and its 18 phyla ''. Microbiological Reviews. 57 ( 4 ) : 953 -- 994. PMC 372943. PMID 8302218. Jump up ^ Cavalier - Smith, Thomas ( 23 June 2010 ). `` Kingdoms Protozoa and Chromista and the eozoan root of the eukaryotic tree ''. Biology Letters. 6 ( 3 ) : 342 -- 345. doi : 10.1098 / rsbl. 2009.0948. PMC 2880060. PMID 20031978. ^ Jump up to : Ruggiero, Michael A. ; Gordon, Dennis P. ; Orrell, Thomas M. ; Bailly, Nicolas ; Bourgoin, Thierry ; Brusca, Richard C. ; Cavalier - Smith, Thomas ; Guiry, Michael D. ; Kirk, Paul M. ( 29 April 2015 ). `` A Higher Level Classification of All Living Organisms ''. PLoS ONE. 10 ( 4 ) : e0119248. Bibcode : 2015PLoSO... 1019248R. doi : 10.1371 / journal. pone. 0119248. PMC 4418965. PMID 25923521. Jump up ^ Bailly, Anatole ( 1981 - 01 - 01 ). Abrégé du dictionnaire grec français. Paris : Hachette. ISBN 2010035283. OCLC 461974285. Jump up ^ Bailly, Anatole. `` Greek - french dictionary online ''. www.tabularium.be. Retrieved 2018 - 10 - 05. Jump up ^ Hogg, John ( 1860 ). `` On the distinctions of a plant and an animal and on a fourth kingdom of Nature ''. Edinb N Phil J ( N Ser ). 12 : 216 -- 225. Jump up ^ Scamardella, J.M. ( December 1999 ). `` Not plants or animals : a brief history of the origin of Kingdoms Protozoa, Protista and Protoctista ''. International Microbiology. 2 ( 4 ) : 207 -- 216. PMID 10943416. Jump up ^ Copeland, Herbert F. ( September -- October 1947 ). `` Progress Report on Basic Classification ''. The American Naturalist. 81 ( 800 ) : 340 -- 361. doi : 10.1086 / 281531. JSTOR 2458229. Jump up ^ Siebold, C. Th. v. `` Details - Lehrbuch der vergleichenden Anatomie der Wirbellosen Thiere ''. Biodiversity Library. Retrieved 20 May 2015. Jump up ^ Dobell, C. ( April 1951 ). `` In memoriam Otto Bütschli ( 1848 - 1920 ) `` architect of protozoology '' ``. Isis ; an International Review Devoted to the History of Science and Its Cultural Influences. 42 ( 127 ) : 20 -- 22. PMID 14831973. ^ Jump up to : Taylor, F.J.R. ' Max ' ( 11 January 2003 ). `` The collapse of the two - kingdom system, the rise of protistology and the founding of the International Society for Evolutionary Protistology ( ISEP ) ''. International Journal of Systematic and Evolutionary Microbiology. 53 ( 6 ) : 1707 -- 1714. doi : 10.1099 / ijs. 0.02587 - 0. PMID 14657097. Jump up ^ Hogg, John ( 1860 ). `` On the distinctions of a plant and an animal, and on a fourth kingdom of nature ''. Edinburgh New Philosophical Journal. Jump up ^ Whittaker, R.H. ( 10 January 1969 ). `` New concepts of kingdoms or organisms. Evolutionary relations are better represented by new classifications than by the traditional two kingdoms ''. Science. 163 ( 3863 ) : 150 -- 160. Bibcode : 1969Sci... 163... 150W. doi : 10.1126 / science. 163.3863. 150. PMID 5762760. Jump up ^ Margulis, Lynn ( 1974 ). `` Five - Kingdom Classification and the Origin and Evolution of Cells ''. In Dobzhansky, Theodosius ; Hecht, Max K. ; Steere, William C. Evolutionary Biology. Springer. pp. 45 -- 78. doi : 10.1007 / 978 - 1 - 4615 - 6944 - 2_2. ISBN 978 - 1 - 4615 - 6946 - 6. Jump up ^ Cavalier - Smith, Thomas ( August 1998 ). `` A revised six - kingdom system of life ''. Biological Reviews. 73 ( 3 ) : 203 -- 266. doi : 10.1111 / j. 1469 - 185X. 1998. tb00030. x. PMID 9809012. Jump up ^ `` New President 's Address ''. protozoa.uga.edu. Retrieved 1 May 2015. Jump up ^ Singleton, Paul ; Sainsbury, Diana ( 2001 ). Dictionary of microbiology and molecular biology. Wiley. ISBN 9780471941507. ^ Jump up to : Gooday, A.J. ; Aranda da Silva, A.P. ; Pawlowski, J. ( 1 December 2011 ). `` Xenophyophores ( Rhizaria, Foraminifera ) from the Nazaré Canyon ( Portuguese margin, NE Atlantic ) ''. Deep - Sea Research Part II : Topical Studies in Oceanography. 58 ( 24 -- 25 ) : 2401 -- 2419. Bibcode : 2011DSRII... 58.2401 G. doi : 10.1016 / j. dsr2. 2011.04. 005. Retrieved 2018 - 04 - 06. Jump up ^ Ghaffar, Abdul. `` Blood and Tissue Protozoa ''. Microbiology and Immunology On - Line. Retrieved 2018 - 03 - 23. Jump up ^ Mylnikov, Alexander P. ; Weber, Felix ; Jürgens, Klaus ; Wylezich, Claudia ( August 2015 ). `` Massisteria marina has a sister : Massisteria voersi sp. nov., a rare species isolated from coastal waters of the Baltic Sea ''. European Journal of Protistology. 51 ( 4 ) : 299 -- 310. doi : 10.1016 / j. ejop. 2015.05. 002. PMID 26163290. Jump up ^ Mitchell, Gary C. ; Baker, J.H. ; Sleigh, M.A. ( 1 May 1988 ). `` Feeding of a freshwater flagellate, Bodo saltans, on diverse bacteria ''. The Journal of Protozoology. 35 ( 2 ) : 219 -- 222. doi : 10.1111 / j. 1550 - 7408.1988. tb04327. x. Jump up ^ Ghaffar, Abdul. `` Blood and tissue Protozoa ''. Microbiology and Immunology On - Line. Retrieved 2018 - 03 - 23. Jump up ^ `` Trypanosoma brucei ''. parasite.org.au. Retrieved 2018 - 03 - 23. Jump up ^ `` Microscopy of Entamoeba histolytica ''. msu.edu. Retrieved 2016 - 08 - 21. Jump up ^ Lehman, Don. `` Diagnostic parasitology ''. University of Delaware. Retrieved 2018 - 03 - 23. Jump up ^ Taylor, Bruce. `` Paramecium caudatum ''. Encyclopedia of Life. Retrieved 2018 - 03 - 23. Jump up ^ `` Amoeba proteus Microworld ''. www.arcella.nl. Retrieved 2016 - 08 - 21. Jump up ^ `` Noctiluca scintillans ''. University of Tasmania, Australia. Retrieved 2018 - 03 - 23. Jump up ^ Sheehan, Kathy B. ( 2005 ). Seen and Unseen : Discovering the Microbes of Yellowstone. Falcon. ISBN 9780762730933. Jump up ^ Post, F.J. ; Borowitzka, L.J. ; Borowitzka, M.A. ; Mackay, B. ; Moulton, T. ( 1983 - 09 - 01 ). `` The protozoa of a Western Australian hypersaline lagoon ''. Hydrobiologia. 105 ( 1 ) : 95 -- 113. doi : 10.1007 / BF00025180. ISSN 0018 - 8158. Jump up ^ `` Termite gut microbes NOLL LAB ''. www.kennethnoll.uconn.edu. Retrieved 2018 - 03 - 21. Jump up ^ Williams, A.G. ; Coleman, G.S. ( 1997 ). The Rumen Microbial Ecosystem. Springer, Dordrecht. pp. 73 -- 139. doi : 10.1007 / 978 - 94 - 009 - 1453 - 7_3. ISBN 9789401071499. Jump up ^ Lee, John J. ; Leedale, Gordon F. ; Bradbury, Phyllis Clarke ( 25 May 2000 ). An illustrated guide to the protozoa : organisms traditionally referred to as protozoa, or newly discovered groups. Society of Protozoologists. p. 634. Jump up ^ Wiser, Mark F. `` Biochemistry of Plasmodium ''. The Wiser Page. Retrieved 2018 - 03 - 22. Jump up ^ Nishitani, Goh ; Nagai, Satoshi ; Baba, Katsuhisa ; Kiyokawa, Susumu ; Kosaka, Yuki ; Miyamura, Kazuyoshi ; Nishikawa, Tetsuya ; Sakurada, Kiyonari ; Shinada, Akiyoshi ( May 2010 ). `` High - Level Congruence of Myrionecta rubra Prey and Dinophysis Species Plastid Identities as Revealed by Genetic Analyses of Isolates from Japanese Coastal Waters ''. Applied and Environmental Microbiology. 76 ( 9 ) : 2791 -- 2798. doi : 10.1128 / AEM. 02566 - 09. PMC 2863437. PMID 20305031. Jump up ^ Protozoa in biological research Jump up ^ `` Sex and Death in Protozoa ''. Cambridge University Press. Retrieved 2015 - 06 - 09. Jump up ^ Bernstein H, Bernstein C ( 2013 ). Bernstein C, Bernstein H eds. Evolutionary Origin and Adaptive Function of Meiosis '. Meiosis. InTech. ISBN 978 - 953 - 51 - 1197 - 9 Jump up ^ Kudo, Richard R. ( Richard Roksabro ) ( 1954 ). Protozoology. MBLWHOI Library. Springfield, Ill., C.C. Thomas. Jump up ^ Honigberg, B.M. ; W. Balamuth ; E.C. Bovee ; J.O. Corliss ; M. Gojdics ; R.P. Hall ; R.R. Kudo ; N.D. Levine ; A.R. Lobblich ; J. Weiser ( February 1964 ). `` A Revised Classification of the Phylum Protozoa ''. Journal of Eukaryotic Microbiology. 11 ( 1 ) : 7 -- 20. doi : 10.1111 / j. 1550 - 7408.1964. tb01715. x. Jump up ^ Adl, Sina M. ; Simpson, Alastair G.B. ; Lane, Christopher E. ; Lukeš, Julius ; Bass, David ; Bowser, Samuel S. ; Brown, Matthew W. ; Burki, Fabien ; Dunthorn, Micah ( 2012 - 09 - 01 ). `` The Revised Classification of Eukaryotes ''. Journal of Eukaryotic Microbiology. 59 ( 5 ) : 429 -- 514. doi : 10.1111 / j. 1550 - 7408.2012. 00644. x. PMC 3483872. Jump up ^ Bartel, Rebecca ; Oberhauser, Karen ; De Roode, Jacob ; Atizer, Sonya ( February 2011 ). `` Monarch butterfly migration and parasite transmission in eastern North America ''. Ecology. 92 ( 2 ) : 342 -- 351. doi : 10.1890 / 10 - 0489.1. PMID 21618914. Jump up ^ Leong, K.L.H. ; M.A. Yoshimura ; H.K. Kaya ; H. Williams ( January 1997 ). `` Instar Susceptibility of the Monarch Butterfly ( Danaus plexippus ) to the Neogregarine Parasite, Ophryocystis elektroscirrha ''. Journal of Invertebrate Pathology. 69 ( 1 ) : 79 -- 83. doi : 10.1006 / jipa. 1996.4634. PMID 9028932. Lay summary. Bibliography General Dogiel, V.A., revised by J.I. Poljanskij and E.M. Chejsin. General Protozoology, 2nd ed., Oxford University Press, 1965. Hausmann, K., N. Hulsmann. Protozoology. Thieme Verlag ; New York, 1996. Kudo, R.R. Protozoology. Springfield, Illinois : C.C. Thomas, 1954 ; 4th ed. Manwell, R.D. Introduction to Protozoology, second revised edition, Dover Publications Inc., New York, 1968. Roger Anderson, O. Comparative protozoology : ecology, physiology, life history. Berlin ( etc. ) : Springer - Verlag, 1988. Sleigh, M. The Biology of Protozoa. E. Arnold : London, 1981. Identification Jahn, T.L. - Bovee, E.C. & Jahn, F.F. How to Know the Protozoa. Wm. C. Brown Publishers, Div. of McGraw Hill, Dubuque, Iowa, 1979 ; 2nd ed. Lee, J.J., Leedale, G.F. & Bradbury, P. An Illustrated Guide to the Protozoa. Lawrence, Kansas, U.S.A : Society of Protozoologists, 2000 ; 2nd ed. Patterson, D.J. Free - Living Freshwater Protozoa. A Colour Guide. Manson Publishing ; London, 1996. Patterson, D.J., M.A. Burford. A Guide to the Protozoa of Marine Aquaculture Ponds. CSIRO Publishing, 2001. Morphology Harrison, F.W., Corliss, J.O. ( ed. ). 1991. Microscopic Anatomy of Invertebrates, vol. 1, Protozoa. New York : Wiley - Liss, 512 pp. Pitelka, D.R. 1963. Electron - Microscopic Structure of Protozoa. Pergamon Press, Oxford. Physiology and biochemistry Nisbet, B. 1984. Nutrition and feeding strategies in Protozoa. Croom Helm Publ., London, 280 pp. Coombs, G.H. & North, M. 1991. Biochemical protozoology. Taylor & Francis, London, Washington. Laybourn - Parry J. 1984. A Functional Biology of Free - Living Protozoa. Berkeley, California : University of California Press. Levandowski, M., S.H. Hutner ( eds ). 1979. Biochemistry and physiology of protozoa. Volumes 1, 2, and 3. Academic Press : New York, NY ; 2nd ed. Sukhareva - Buell, N.N. 2003. Biologically active substances of protozoa. Dordrecht : Kluwer. Ecology Capriulo, G.M. ( ed. ). 1990. Ecology of Marine Protozoa. Oxford Univ. Press, New York. Darbyshire, J.F. ( ed. ). 1994. Soil Protozoa. CAB International : Wallingford, U.K. 2009 pp. Laybourn - Parry, J. 1992. Protozoan plankton ecology. Chapman & Hall, New York. 213 pp. Fenchel, T. 1987. Ecology of protozoan : The biology of free - living phagotrophic protists. Springer - Verlag, Berlin. 197 pp. Parasitology Kreier, J.P. ( ed. ). 1991 - 1995. Parasitic Protozoa, 2nd ed. 10 vols ( 1 - 3 coedited by Baker, J.R. ). Academic Press, San Diego, California, ( 1 ). Methods Lee, J.J., & Soldo, A.T. ( 1992 ). Protocols in protozoology. Kansas, USA : Society of Protozoologists, Lawrence, ( 2 ). External links Wikispecies has information related to Protozoa Chisholm, Hugh, ed. ( 1911 ). `` Protozoa ''. Encyclopædia Britannica ( 11th ed. ). Cambridge University Press. Infectious disease and microbiology Disciplines ( pathogens ) Major diseases Bacteriology ( bacteria ) Cholera Diphtheria Leprosy Syphilis Tuberculosis Virology ( viruses, prions ) AIDS Influenza Measles Polio Smallpox Mycology ( fungi ) Aspergillosis Candidiasis Tinea Parasitology ( protozoa, helminths ) Amoebic dysentery Hookworm Malaria Schistosomiasis Entomology ( ectoparasites ) Lice Scabies People Alexander Fleming Edward Jenner Robert Koch Louis Pasteur Ignaz Semmelweis Related topics Antibiotics Eradication Pandemic Transmission horizontal vertical Vaccination Zoonosis Eukaryota Domain Archaea Bacteria Eukaryota ( Supergroup Plant Hacrobia Heterokont Alveolata Rhizaria Excavata Amoebozoa Opisthokonta Animal Fungi ) Diaphoretickes Archaeplastida Glaucophyta Rhodophyta Green algae Plantae s.s. Chlorophyta Streptophyta Chlorokybophyceae Mesostigmatophyceae Spirotaenia Cryptista Corbihelia Cryptophyta A + H Ancoracysta twista Haptista Centroheliozoa Haptophyta TSAR SAR Halvaria Alveolata Ciliates Miozoa Acavomonadia Colponemidia Myzozoa Stramenopiles ( heterokonts ) Bicosoecea Developea Hyphochytrea Ochrophyta Peronosporomycota Pirsoniomycota Placidozoa Platysulcea Sagenista Rhizaria Filosa Phytomyxea Retaria Ectoreta Marimyxia Vampyrellidea Telonemia Incertae sedis Kamera lens Discoba Eolouka Jakobea Tsukubea Discicristata Euglenozoa Percolozoa Loukozoa Ancyromonadida Malawimonadea Metamonada ( Anaeromonada, Trichozoa ) Podiata Amorphea Amoebozoa Conosa ( Archamoebae, Semiconosia ) Lobosa ( Cutosea, Discosea, Tubulinea ) Obazoa Apusomonadida Breviatea Opisthokonta Holomycota Cristidiscoidea Zoosporia Opisthosporidia True fungi Holozoa Ichthyosporea Pluriformea Syssomonas Corallochytrea Filozoa Choanoflagellates Filasterea Metazoa or Animals CRuMs Diphyllatea Mantamonadida Rigifilida Micronucleariida ? Incertae sedis Parakaryon myojinensis † Acritarcha † Charnia † Gakarusia † Galaxiopsis † Grypania † Leptoteichos Major kingdoms are underlined. See also : protist. Sources and alternative views : Wikispecies. Microbiology : Protistology : Protists Former classifications Protozoa Mastigophora / Flagellates Sarcodina / Amoeboids Testate Heliozoa Infusoria / Ciliates Sporozoa Algae Cryptogams Thallophytes Fungus - like organisms Slime molds Ambiregnal protists Morphology Archaeplastida Chloroplastida `` green algae '' : Phycoplast Phragmoplast Flagellar apparatus Glaucophytes : Cyanelles Phycobilisomes Red algae : Pit connection Phycobilisomes Hacrobia Cryptophyta : Mastigonemes Periplast Haptophyte : Coccolith Haptonema Stramenopiles General : Mastigonemes Diatoms : Frustule Brown algae : Lamina Pneumatocyst Alveolata General : Alveoli Trichocyst Dinoflagellates : Dinokaryon Dinocyst Theca Ciliates : Cilium Cirrus Macronucleus Micronucleus Apicomplexans : Rhoptry Apicoplast Microneme Rhizaria Phytomyxea Cruciform division Excavate Kinetoplastids : Kinetoplast Glycosome Euglenoidea : Periplast / pellicle Amoebozoa Dictyostelids : Macrocyst Sorocarp Opisthokonta Choanoflagellates : Collar of microvilli General Levels of organization Unicellular Monadoid Amoeboid Coccoid Colonial s.s. Colonial flagellated Tetrasporal / capsal / palmelloid Sarcinoid Coenobial Filamentous / trichal / hyphal Parenchymatous Pseudoparenchymatous / plektenchymatic Membranous / thalloid / foliaceous Multinucleated Syncytial Coenocytic Siphonous Siphonocladous Multicellular s.s. / tissular / histonal Cell surface structures Simple cell membrane Mucilage Scale Frustule Cell wall Lorica Skeleton Test Theca Periplast / pellicle Locomotion Flagellum Cilium Pseudopodia Gliding motility Mitochondria Hydrogenosome Mitosome Nucleus Nucleomorph Multinucleate cells Plasmodium Dikaryon Heterokaryon Mitosis in protists Open Closed Orthomitosis Pleuromitosis Meiosis in protists Gametic Zygotic Sporic Other Cyst Cytostome Fimbriae Extrusome Contractile vacuole Eyespot apparatus Pyrenoid Axostyle Mastigont system Ecology and physiology Microbial ecology Microbial biogeography Baas - Becking hypothesis Development / Reproduction Life cycles Fertilization Nutrition : Autotrophy Phototrophy Heterotrophy Phagotrophy Osmotrophy Saprotrophy Parasitism Biotrophy Necrotrophy Mixotrophy Auxotrophy Taxon identifiers Wikidata : Q101274 Wikispecies : Protozoa EoL : 4651 Fossilworks : 71297 GBIF : 7 iNaturalist : 47686 ITIS : 630577 NZOR : 8dca8b6a - da01 - 4124 - 888c - 5aca5f3e328c uBio : 486669 WoRMS : 5 GND : 4132686 - 6 NDL : 00562365 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Protozoa&oldid=866114343 '' Categories : 1670s in science Obsolete eukaryote taxa Paraphyletic groups Microscopic organisms described by Antonie van Leeuwenhoek Hidden categories : Articles with short description Articles containing German - language text All articles with unsourced statements Articles with unsourced statements from September 2018 Wikipedia articles incorporating a citation from the 1911 Encyclopaedia Britannica with Wikisource reference Wikipedia articles with GND identifiers Wikipedia articles with NDL identifiers Talk Contents About Wikipedia Wikispecies Alemannisch Asturianu Azərbaycanca تۆرکجه Беларуская Bosanski Català Čeština Dansk Deutsch Eesti Ελληνικά Español Esperanto Euskara فارسی Français Gaeilge Gaelg Galego 한국어 Հայերեն हिन्दी Hrvatski Ido Bahasa Indonesia Interlingua Íslenska Italiano עברית Basa Jawa ქართული Қазақша Kreyòl ayisyen Кыргызча Latina Latviešu Lietuvių Limburgs Magyar Македонски മലയാളം Bahasa Melayu Nederlands 日本 語 Norsk Norsk nynorsk Occitan ਪੰਜਾਬੀ پنجابی Plattdüütsch Polski Português Română Русский Scots Simple English Slovenčina Slovenščina کوردی Српски / srpski Srpskohrvatski / српскохрватски Basa Sunda Suomi Svenska Tagalog தமிழ் తెలుగు ไทย Тоҷикӣ Türkçe Українська اردو Tiếng Việt Walon 中文 68 more Edit links This page was last edited on 28 October 2018, at 10 : 02 ( UTC ). Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: protozoan classification used to be based on their means of
Answer: locomotion