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64-396: Tamil Nadu Pollution Control Board is the governing body to monitor and control air, noise, and water pollution in the state of Tamil Nadu . This Tamil Nadu related article is a stub . You can help Misplaced Pages by expanding it . Water pollution Water pollution (or aquatic pollution ) is the contamination of water bodies , with a negative impact on their uses. It

128-594: 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 ζῷα ( zôia ), plural of ζῷον ( zôion ), meaning "animal". In 1848, with better microscopes and Theodor Schwann and Matthias Schleiden 's cell theory ,

192-466: A phylum containing two broad classes of microorganisms: Infusoria (mostly ciliates ) and flagellates (flagellated protists and amoebae ). The definition of Protozoa as a phylum or sub-kingdom composed of "unicellular animals" was adopted by the zoologist Otto Bütschli —celebrated at his centenary as the "architect of protozoology". As a phylum under Animalia, the Protozoa were firmly rooted in

256-548: A wastewater treatment plant or an oil spill . Non-point sources are more diffuse. An example is agricultural runoff . Pollution is the result of the cumulative effect over time. Pollution may take many forms. One would is toxic substances such as oil, metals, plastics, pesticides , persistent organic pollutants , and industrial waste products. Another is stressful conditions such as changes of pH , hypoxia or anoxia, increased temperatures, excessive turbidity , or changes of salinity ). The introduction of pathogenic organisms

320-496: A biomonitor or bioindicator is described as biological monitoring . This refers to the measurement of specific properties of an organism to obtain information on the surrounding physical and chemical environment. Biological testing involves the use of plant, animal or microbial indicators to monitor the health of an aquatic ecosystem . They are any biological species or group of species whose function, population, or status can reveal what degree of ecosystem or environmental integrity

384-491: A fourth treatment stage which not many plants have. Solid waste can enter water bodies through untreated sewage, combined sewer overflows, urban runoff, people discarding garbage into the environment, wind carrying municipal solid waste from landfills and so forth. This results in macroscopic pollution– large visible items polluting the water– but also microplastics pollution that is not directly visible. The terms marine debris and marine plastic pollution are used in

448-478: A host's red blood cell. Protozoa may also live as mixotrophs , combining a heterotrophic diet with some form of autotrophy . Some protozoa form close associations with symbiotic photosynthetic algae (zoochlorellae), which live and grow within the membranes of the larger cell and provide nutrients to the host. The algae are not digested, but reproduce and are distributed between division products. The organism may benefit at times by deriving some of its nutrients from

512-660: A loose way to describe single-celled protists (that is, eukaryotes that are not animals, plants , or fungi ) that feed by heterotrophy . Traditional textbook examples of protozoa are Amoeba , Paramecium , Euglena and Trypanosoma . The word "protozoa" (singular protozoon ) was coined in 1818 by zoologist Georg August Goldfuss (=Goldfuß), as the Greek equivalent of the German Urthiere , meaning "primitive, or original animals" ( ur- 'proto-' + Thier 'animal'). Goldfuss created Protozoa as

576-402: A lorica made from silicous sectretions. Loricas are also common among some green euglenids, various ciliates (such as the folliculinids , various testate amoebae and foraminifera . The surfaces of a variety of protozoa are covered with a layer of scales and or spicules. Examples include the amoeba Cochliopodium , many centrohelid heliozoa , synurophytes . The layer is often assumed to have

640-413: A low cost treatment option for sewage. UV light (sunlight) can be used to degrade some pollutants in waste stabilization ponds (sewage lagoons). The use of safely managed sanitation services would prevent water pollution caused by lack of access to sanitation. Well-designed and operated systems (i.e., with secondary treatment stages or more advanced tertiary treatment) can remove 90 percent or more of

704-492: A moist habitat; however, some can survive for long periods of time in dry environments, by forming resting cysts that enable them to remain dormant until conditions improve. All protozoa are heterotrophic , deriving nutrients from other organisms, either by ingesting them whole by phagocytosis or taking up dissolved organic matter or micro-particles ( osmotrophy ). Phagocytosis may involve engulfing organic particles with pseudopodia (as amoebae do), taking in food through

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768-541: A new kingdom called Primigenum, consisting of both the protozoa and unicellular algae, which he combined 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. In 1866, Ernst Haeckel 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

832-558: A protective role. In some, such as the actinophryid heliozoa, the scales only form when the organism encysts. The bodies of some protozoa are supported internally by rigid, often inorganic, elements (as in Acantharea , Pylocystinea , Phaeodarea  – collectively the ' radiolaria ', and Ebriida ). Protozoa mostly reproduce asexually by binary fission or multiple fission. Many protozoa also exchange genetic material by sexual means (typically, through conjugation ), but this

896-484: A rigid external cell wall but are usually enveloped by elastic structures of membranes that permit movement of the cell. In some protozoa, such as the ciliates and euglenozoans , the outer membrane of the cell is supported by a cytoskeletal infrastructure, which may be referred to as a "pellicle". The pellicle gives shape to the cell, especially during locomotion. Pellicles of protozoan organisms vary from flexible and elastic to fairly rigid. In ciliates and Apicomplexa ,

960-489: A simplistic "two-kingdom" concept 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

1024-452: A specialized mouth-like aperture called a cytostome , or using stiffened ingestion organelles Parasitic protozoa 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

1088-666: A waterway from a single, identifiable source, such as a pipe or ditch . Examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain . The U.S. Clean Water Act (CWA) defines point source for regulatory enforcement purposes ( see United States regulation of point source water pollution ). The CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites. Sewage typically consists of 99.9% water and 0.1% solids. Sewage contributes many classes of nutrients that lead to Eutrophication . It

1152-703: A wide spectrum of chemicals , pathogens, and physical changes such as elevated temperature. While many of the chemicals and substances that are regulated may be naturally occurring ( calcium , sodium , iron, manganese , etc.) the concentration usually determines what is a natural component of water and what is a contaminant. High concentrations of naturally occurring substances can have negative impacts on aquatic flora and fauna. Oxygen-depleting substances may be natural materials such as plant matter (e.g. leaves and grass) as well as human-made chemicals. Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs

1216-463: Is a form of water pollution as well. It causes biological pollution . In many areas of the world, groundwater pollution poses a hazard to the wellbeing of people and ecosystems. One-quarter of the world's population depends on groundwater for drinking, yet concentrated recharging is known to carry short-lived contaminants into carbonate aquifers and jeopardize the purity of those waters. Point source water pollution refers to contaminants that enter

1280-569: Is a major source of phosphate for example. Sewage is often contaminated with diverse compounds found in personal hygiene , cosmetics , pharmaceutical drugs (see also drug pollution ), and their metabolites Water pollution due to environmental persistent pharmaceutical pollutants can have wide-ranging consequences. When sewers overflow during storm events this can lead to water pollution from untreated sewage. Such events are called sanitary sewer overflows or combined sewer overflows . Industrial processes that use water also produce wastewater. This

1344-513: Is a process whereby air pollutants from industrial or natural sources settle into water bodies. The deposition may lead to polluted water near the source, or at distances up to a few thousand miles away. The most frequently observed water pollutants resulting from industrial air deposition are sulfur compounds, nitrogen compounds, mercury compounds, other heavy metals, and some pesticides and industrial by-products. Natural sources of air deposition include forest fires and microbial activity. Acid rain

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1408-413: Is an increase in the concentration of chemical nutrients in an ecosystem to an extent that increases the primary productivity of the ecosystem. Subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions in water quality may occur. This can harm fish and other animal populations. Ocean acidification is another impact of water pollution. Ocean acidification

1472-626: Is another. Contaminants may include organic and inorganic substances. A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers. Control of water pollution requires appropriate infrastructure and management plans as well as legislation. Technology solutions can include improving sanitation , sewage treatment , industrial wastewater treatment , agricultural wastewater treatment , erosion control , sediment control and control of urban runoff (including stormwater management). A practical definition of water pollution is: "Water pollution

1536-480: Is being investigated since at least the 1990s. PPCPs include substances used by individuals for personal health or cosmetic reasons and the products used by agribusiness to boost growth or health of livestock. More than twenty million tons of PPCPs are produced every year. The European Union has declared pharmaceutical residues with the potential of contamination of water and soil to be "priority substances". PPCPs have been detected in water bodies throughout

1600-469: Is called industrial wastewater . Using the US as an example, the main industrial consumers of water (using over 60% of the total consumption) are power plants, petroleum refineries, iron and steel mills, pulp and paper mills, and food processing industries. Some industries discharge chemical wastes, including solvents and heavy metals (which are toxic) and other harmful pollutants. Industrial wastewater could add

1664-462: Is caused by emissions of sulfur dioxide and nitrogen oxide , which react with the water molecules in the atmosphere to produce acids. Some governments have made efforts since the 1970s to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere. The main source of sulfur and nitrogen compounds that result in acid rain are anthropogenic , but nitrogen oxides can also be produced naturally by lightning strikes and sulphur dioxide

1728-487: Is generally decoupled from reproduction. Meiotic sex is widespread among eukaryotes , and must have originated early in their evolution, as it has been found in many protozoan lineages that diverged early in eukaryotic evolution. In the well-studied protozoan species Paramecium tetraurelia , the asexual line undergoes clonal aging, loses vitality and expires after about 200 fissions if the cells fail to undergo autogamy or conjugation. The functional basis for clonal aging

1792-545: Is mandatory regulations, which are only part of the solution. Other important tools in pollution control include environmental education, economic instruments, market forces, and stricter enforcement. Standards can be "precise" (for a defined quantifiable minimum or maximum value for a pollutant), or "imprecise" which would require the use of Best available technology (BAT) or Best practicable environmental option (BPEO). Market-based economic instruments for pollution control can include charges, subsidies, deposit or refund schemes,

1856-514: Is meant by the word 'Protozoa', the need for disambiguating statements such as "in the sense intended by Goldfuß", and the problems that arise when new meanings are given to familiar taxonomic terms. Some authors classify Protozoa as a subgroup of mostly motile Protists. Others class any unicellular eukaryotic microorganism as Protists, and make no reference to 'Protozoa'. In 2005, members of the Society of Protozoologists voted to change its name to

1920-518: Is present. One example of a group of bio-indicators are the copepods and other small water crustaceans that are present in many water bodies. Such organisms can be monitored for changes (biochemical, physiological, or behavioral) that may indicate a problem within their ecosystem. Water pollution is a major global environmental problem because it can result in the degradation of all aquatic ecosystems – fresh, coastal, and ocean waters. The specific contaminants leading to pollution in water include

1984-658: Is produced by volcanic eruptions . Acid rain can have harmful effects on plants, aquatic ecosystems and infrastructure. Carbon dioxide concentrations in the atmosphere have increased since the 1850s due anthropogenic influences ( emissions of greenhouse gases ). This leads to ocean acidification and is another form of water pollution from atmospheric contributions. Water pollution may be analyzed through several broad categories of methods: physical, chemical and biological. Some methods may be conducted in situ , without sampling, such as temperature. Others involve collection of samples, followed by specialized analytical tests in

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2048-762: Is rare among free-living protozoa and it usually occurs when food is scarce or the environment changes drastically. Both isogamy and anisogamy occur in Protozoa, anisogamy being the more common form of sexual reproduction. Protozoans, 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. Free-living protozoa 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

2112-413: Is the degradation of aquatic ecosystems . Another is spreading water-borne diseases when people use polluted water for drinking or irrigation . Water pollution also reduces the ecosystem services such as drinking water provided by the water resource . Sources of water pollution are either point sources or non-point sources . Point sources have one identifiable cause, such as a storm drain ,

2176-906: Is the addition of substances or energy forms that directly or indirectly alter the nature of the water body in such a manner that negatively affects its legitimate uses." Water is typically referred to as polluted when it is impaired by anthropogenic contaminants. Due to these contaminants, it either no longer supports a certain human use, such as drinking water , or undergoes a marked shift in its ability to support its biotic communities, such as fish. The following compounds can all reach water bodies via raw sewage or even treated sewage discharges: Inadequately treated wastewater can convey nutrients, pathogens, heterogenous suspended solids and organic fecal matter. Bacteria, viruses, protozoans and parasitic worms are examples of pathogens that can be found in wastewater. In practice, indicator organisms are used to investigate pathogenic pollution of water because

2240-510: Is the ongoing decrease in the pH value of the Earth's oceans, caused by the uptake of carbon dioxide (CO 2 ) from the atmosphere. Water pollution is a problem in developing countries as well as in developed countries . For example, water pollution in India and China is widespread. About 90 percent of the water in the cities of China is polluted. One aspect of environmental protection

2304-505: Is usually a result of human activities. Water bodies include lakes , rivers , oceans , aquifers , reservoirs and groundwater . Water pollution results when contaminants mix with these water bodies. Contaminants can come from one of four main sources. These are sewage discharges, industrial activities, agricultural activities, and urban runoff including stormwater . Water pollution may affect either surface water or groundwater . This form of pollution can lead to many problems. One

2368-906: The Schistosoma type. The source of high levels of pathogens in water bodies can be from human feces (due to open defecation ), sewage, blackwater , or manure that has found its way into the water body. The cause for this can be lack of sanitation procedures or poorly functioning on-site sanitation systems ( septic tanks , pit latrines ), sewage treatment plants without disinfection steps, sanitary sewer overflows and combined sewer overflows (CSOs) during storm events and intensive agriculture (poorly managed livestock operations). Organic substances that enter water bodies are often toxic . Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants . Inorganic water pollutants include for example: The environmental effect of pharmaceuticals and personal care products (PPCPs)

2432-558: The Joint Monitoring Programme for Water Supply and Sanitation . Lack of access to sanitation is concerning and often leads to water pollution, e.g. via the practice of open defecation : during rain events or floods, the human feces are moved from the ground where they were deposited into surface waters. Simple pit latrines may also get flooded during rain events. As of 2022, Europe and Central Asia account for around 16% of global microplastics discharge into

2496-490: The gills of some fish species. A study published in 2017 stated that "polluted water spread gastrointestinal diseases and parasitic infections and killed 1.8 million people" (these are also referred to as waterborne diseases). Persistent exposure to pollutants through water are environmental health hazards, which can increase the likelihood for one to develop cancer or other diseases. Nitrogen pollution can cause eutrophication, especially in lakes. Eutrophication

2560-451: The pollutant load in sewage. Some plants have additional systems to remove nutrients and pathogens. While such advanced treatment techniques will undoubtedly reduce the discharges of micropollutants, they can also result in large financial costs, as well as environmentally undesirable increases in energy consumption and greenhouse gas emissions . Sewer overflows during storm events can be addressed by timely maintenance and upgrades of

2624-421: The sewerage system . In the US, cities with large combined systems have not pursued system-wide separation projects due to the high cost, but have implemented partial separation projects and green infrastructure approaches. In some cases municipalities have installed additional CSO storage facilities or expanded sewage treatment capacity. Protozoan When first introduced by Georg Goldfuss , in 1818,

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2688-571: The International Society of Protistologists . In the system of eukaryote classification published by the International Society of Protistologists in 2012, members of the old phylum Protozoa have been distributed among a variety of supergroups. Protistans are distributed across all major groups of eukaryotes, including those that contain multicellular algae, green plants, animals, and fungi. If photosynthetic and fungal protistans are distinguished from protozoa, they appear as shown in

2752-544: The Kingdoms Protista and Protoctista became established in biology texts and curricula. By 1954, Protozoa were classified as "unicellular animals", as distinct from the "Protophyta", single-celled photosynthetic algae, which were considered primitive plants. In the system of classification published in 1964 by B.M. Honigsberg and colleagues, the phylum Protozoa was divided according to the means of locomotion, such as by cilia or flagella. Despite awareness that

2816-470: 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, the old "two kingdom" system began to weaken, with

2880-525: The algal endosymbionts or by surviving anoxic conditions because of the oxygen produced by algal photosynthesis. Some protozoans 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. The symbionts may be passed along to dinoflagellates of

2944-497: The context of pollution of oceans. Microplastics persist in the environment at high levels, particularly in aquatic and marine ecosystems , where they cause water pollution. 35% of all ocean microplastics come from textiles/clothing, primarily due to the erosion of polyester, acrylic, or nylon-based clothing, often during the washing process. Stormwater, untreated sewage and wind are the primary conduits for microplastics from land to sea. Synthetic fabrics, tyres, and city dust are

3008-1188: The creation of a market in pollution credits, and enforcement incentives. Moving towards a holistic approach in chemical pollution control combines the following approaches: Integrated control measures, trans-boundary considerations, complementary and supplementary control measures, life-cycle considerations , the impacts of chemical mixtures. Control of water pollution requires appropriate infrastructure and management plans. The infrastructure may include wastewater treatment plants , for example sewage treatment plants and industrial wastewater treatment plants. Agricultural wastewater treatment for farms, and erosion control at construction sites can also help prevent water pollution. Effective control of urban runoff includes reducing speed and quantity of flow. Water pollution requires ongoing evaluation and revision of water resource policy at all levels (international down to individual aquifers and wells). Municipal wastewater can be treated by centralized sewage treatment plants, decentralized wastewater systems , nature-based solutions or in onsite sewage facilities and septic tanks. For example, waste stabilization ponds can be

3072-701: The detection of pathogenic organisms in water sample is difficult and costly, because of their low concentrations. The indicators ( bacterial indicator ) of fecal contamination of water samples most commonly used are total coliforms (TC) or fecal coliforms (FC), the latter also referred to as thermotolerant coliforms, such as Escherichia coli . Pathogens can produce waterborne diseases in either human or animal hosts. Some microorganisms sometimes found in contaminated surface waters that have caused human health problems include Burkholderia pseudomallei , Cryptosporidium parvum , Giardia lamblia , Salmonella , norovirus and other viruses, and parasitic worms including

3136-487: The following pollutants to receiving water bodies if the wastewater is not treated and managed properly: Agriculture is a major contributor to water pollution from nonpoint sources. The use of fertilizers as well as surface runoff from farm fields, pastures and feedlots leads to nutrient pollution. In addition to plant-focused agriculture, fish-farming is also a source of pollution. Additionally, agricultural runoff often contains high levels of pesticides. Air deposition

3200-573: 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. 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 undulating and beating flagella ). Ciliates (which move by using hair-like structures called cilia ) and amoebae (which move by

3264-482: 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

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3328-869: The laboratory. Standardized, validated analytical test methods, for water and wastewater samples have been published. Common physical tests of water include temperature, Specific conductance or electrical conductance (EC) or conductivity, solids concentrations (e.g., total suspended solids (TSS)) and turbidity . Water samples may be examined using analytical chemistry methods. Many published test methods are available for both organic and inorganic compounds. Frequently used parameters that are quantified are pH , BOD, chemical oxygen demand (COD), dissolved oxygen (DO), total hardness , nutrients ( nitrogen and phosphorus compounds, e.g. nitrate and orthophosphates ), metals (including copper, zinc , cadmium , lead and mercury ), oil and grease, total petroleum hydrocarbons (TPH), surfactants and pesticides . The use of

3392-576: 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 , like plants, but can also feed on organic matter and are motile , like animals. 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

3456-485: The most common sources of microplastics. These three sources account for more than 80% of all microplastic contamination. Surface water pollution includes pollution of rivers, lakes and oceans. A subset of surface water pollution is marine pollution which affects the oceans. Nutrient pollution refers to contamination by excessive inputs of nutrients . Globally, about 4.5 billion people do not have safely managed sanitation as of 2017, according to an estimate by

3520-590: The pellicle includes a layer of closely packed vesicles called alveoli. In euglenids , the pellicle 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). Some protozoa live within loricas – loose fitting but not fully intact enclosures. For example, many collar flagellates ( Choanoflagellates ) have an organic lorica or

3584-1338: The phylogenetic tree of eukaryotic groups. The Metamonada are hard to place, being sister possibly to Discoba , possibly to Malawimonada . Ancyromonadida FLAGELLATE PROTOZOA Malawimonada FLAGELLATE PROTOZOA CRuMs PROTOZOA, often FLAGELLATE Amoebozoa AMOEBOID PROTOZOA Breviatea PARASITIC PROTOZOA Apusomonadida FLAGELLATE PROTOZOA Holomycota ( inc. multicellular fungi ) FUNGAL PROTISTS Holozoa ( inc. multicellular animals ) AMOEBOID PROTOZOA ? Metamonada FLAGELLATE PROTOZOA Discoba EUGLENOID PROTISTS (some photosynthetic), FLAGELLATE/AMOEBOID PROTOZOA Cryptista PROTISTS (algae) Rhodophyta ( multicellular red algae ) PROTISTS (red algae) Picozoa PROTISTS (algae) Glaucophyta PROTISTS (algae) Viridiplantae ( inc. multicellular plants ) PROTISTS (green algae) Hemimastigophora FLAGELLATE PROTOZOA Provora FLAGELLATE PROTOZOA Haptista PROTOZOA Telonemia FLAGELLATE PROTOZOA Rhizaria PROTOZOA, often AMOEBOID Alveolata PROTOZOA Stramenopiles FLAGELLATE PROTISTS (photosynthetic) Reproduction in Protozoa can be sexual or asexual. Most Protozoa reproduce asexually through binary fission . Many parasitic Protozoa reproduce both asexually and sexually . However, sexual reproduction

3648-419: The protozoa, such as the ciliates , dinoflagellates , foraminifera , and the parasitic apicomplexans , which were moved to other groups such as Alveolata and Stramenopiles , under the polyphyletic Chromista . The Protozoa in this scheme were paraphyletic , because it excluded some descendants of Protozoa. The continued use by some of the 'Protozoa' in its old sense highlights the uncertainty as to what

3712-748: The seas, and although management of plastic waste and its recycling is improving globally, the absolute amount of plastic pollution continues to increase unabated due to the large amount of plastic that is being produced and disposed of. Even if sea plastic pollution were to stop entirely, microplastic contamination of the surface ocean would be projected to continue to increase. Elevated water temperatures decrease oxygen levels (due to lower levels of dissolved oxygen , as gases are less soluble in warmer liquids), which can kill fish (which may then rot) and alter food chain composition, reduce species biodiversity , and foster invasion by new thermophilic species. The introduction of aquatic invasive organisms

3776-484: The similarly paraphyletic Protoctista or Protista . By the 1970s, it became usual to require that all taxa be monophyletic (derived from a common ancestor that would also be regarded as protozoan), and holophyletic (containing all of the known descendants of that common ancestor). The taxon 'Protozoa' fails to meet these standards, so grouping protozoa with animals, and treating them as closely related, became no longer justifiable. The term continues to be used in

3840-538: The taxon Protozoa was erected as a class within the Animalia, with the word 'protozoa' meaning "first animals", because they often possess animal -like behaviours, such as motility and predation , and lack a cell wall , as found in plants and many algae . This classification remained widespread in the 19th and early 20th century, and even became elevated to a variety of higher ranks, including phylum , subkingdom , kingdom , and then sometimes included within

3904-761: The traditional Protozoa was not a clade , a natural group with a common ancestor, some authors have continued to use the name, while applying it to differing scopes of organisms. In a series of classifications by Thomas Cavalier-Smith and collaborators since 1981, the taxon Protozoa was applied to certain groups of eukaryotes, and ranked as a kingdom. A scheme presented by Ruggiero et al. in 2015, placed eight not closely related phyla within Kingdom Protozoa: Euglenozoa , Amoebozoa , Metamonada , Choanozoa sensu Cavalier-Smith, Loukozoa , Percolozoa , Microsporidia and Sulcozoa . This approach excludes several major groups traditionally placed among

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3968-571: The use of temporary extensions of cytoplasm called pseudopodia ). Many protozoa, such as the agents of amoebic meningitis, use both pseudopodia and flagella. Some protozoa attach to the substrate or form cysts, so they do not move around ( sessile ). Most sessile protozoa are able to move around at some stage in the life cycle, such as after cell division. The term 'theront' has been used for actively motile phases, as opposed to 'trophont' or 'trophozoite' that refers to feeding stages. Unlike plants, fungi and most types of algae, most protozoa do not have

4032-457: The world. More research is needed to evaluate the risks of toxicity , persistence, and bioaccumulation , but the current state of research shows that personal care products impact the environment and other species, such as coral reefs and fish. PPCPs encompass environmental persistent pharmaceutical pollutants (EPPPs) and are one type of persistent organic pollutants . They are not removed in conventional sewage treatment plants but require

4096-399: The zoologist C. T. von Siebold proposed that the bodies of protozoa such as ciliates and amoebae consisted 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

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