title: Climate change

text: Although there is no single pathway to limit global warming to 1.5 or 2 °C, most scenarios and strategies see a major increase in the use of renewable energy in combination with increased energy efficiency measures to generate the needed greenhouse gas reductions. To reduce pressures on ecosystems and enhance their carbon sequestration capabilities, changes would also be necessary in agriculture and forestry, such as preventing deforestation and restoring natural ecosystems by reforestation.


title: Climate change

text: Other approaches to mitigating climate change have a higher level of risk. Scenarios that limit global warming to 1.5 °C typically project the large-scale use of carbon dioxide removal methods over the 21st century. There are concerns, though, about over-reliance on these technologies, and environmental impacts. Solar radiation management (SRM) is also a possible supplement to deep reductions in emissions. However, SRM would raise significant ethical and legal issues, and the risks are poorly understood.


title: Climate change

text: Renewable energy is key to limiting climate change. Fossil fuels accounted for 80% of the world's energy in 2018. The remaining share was split between nuclear power and renewables (including hydropower, bioenergy, wind and solar power and geothermal energy). That mix is projected to change significantly over the next 30 years. Solar panels and onshore wind are now among the cheapest forms of adding new power generation capacity in many locations. Renewables represented 75% of all new electricity generation installed in 2019, nearly all solar and wind. Other forms of clean energy, such as nuclear and hydropower, currently have a larger share of the energy supply. However, their future growth forecasts appear limited in comparison.


title: Climate change

text: To achieve carbon neutrality by 2050, renewable energy would become the dominant form of electricity generation, rising to 85% or more by 2050 in some scenarios. Investment in coal would be eliminated and coal use nearly phased out by 2050.


title: Climate change

text: Electricity generated from renewable sources would also need to become the main energy source for heating and transport. Transport can switch away from internal combustion engine vehicles and towards electric vehicles, public transit, and active transport (cycling and walking). For shipping and flying, low-carbon fuels would reduce emissions. Heating could be increasingly decarbonised with technologies like heat pumps.


title: Climate change

text: There are obstacles to the continued rapid growth of clean energy, including renewables. For wind and solar, there are environmental and land use concerns for new projects. Wind and solar also produce energy intermittently and with seasonal variability. Traditionally, hydro dams with reservoirs and conventional power plants have been used when variable energy production is low. Going forward, battery storage can be expanded, energy demand and supply can be matched, and long-distance transmission can smooth variability of renewable outputs. Bioenergy is often not carbon-neutral and may have negative consequences for food security. The growth of nuclear power is constrained by controversy around nuclear waste, nuclear weapon proliferation, and accidents. Hydropower growth is limited by the fact that the best sites have been developed, and new projects are confronting increased social and environmental concerns.


title: Climate change

text: Low-carbon energy improves human health by minimising climate change. It also has the near-term benefit of reducing air pollution deaths, which were estimated at 7 million annually in 2016. Meeting the Paris Agreement goals that limit warming to a 2 °C increase could save about a million of those lives per year by 2050, whereas limiting global warming to 1.5 °C could save millions and simultaneously increase energy security and reduce poverty.


title: Climate change

text: Reducing energy demand is another major aspect of reducing emissions. If less energy is needed, there is more flexibility for clean energy development. It also makes it easier to manage the electricity grid, and minimises carbon-intensive infrastructure development. Major increases in energy efficiency investment will be required to achieve climate goals, comparable to the level of investment in renewable energy. Several COVID-19 related changes in energy use patterns, energy efficiency investments, and funding have made forecasts for this decade more difficult and uncertain.


title: Climate change

text: Strategies to reduce energy demand vary by sector. In transport, passengers and freight can switch to more efficient travel modes, such as buses and trains, or use electric vehicles. Industrial strategies to reduce energy demand include improving heating systems and motors, designing less energy-intensive products, and increasing product lifetimes. In the building sector the focus is on better design of new buildings, and higher levels of energy efficiency in retrofitting. The use of technologies like heat pumps can also increase building energy efficiency.


title: Climate change

text: Agriculture and forestry face a triple challenge of limiting greenhouse gas emissions, preventing the further conversion of forests to agricultural land, and meeting increases in world food demand. A set of actions could reduce agriculture and forestry-based emissions by two thirds from 2010 levels. These include reducing growth in demand for food and other agricultural products, increasing land productivity, protecting and restoring forests, and reducing greenhouse gas emissions from agricultural production.


title: Climate change

text: On the demand side, a key component of reducing emissions is shifting people towards plant-based diets. Eliminating the production of livestock for meat and dairy would eliminate about 3/4ths of all emissions from agriculture and other land use. Livestock also occupy 37% of ice-free land area on Earth and consume feed from the 12% of land area used for crops, driving deforestation and land degradation.


title: Climate change

text: Steel and cement production are responsible for about 13% of industrial emissions. In these industries, carbon-intensive materials such as coke and lime play an integral role in the production, so that reducing emissions requires research into alternative chemistries.


title: Climate change

text: Natural carbon sinks can be enhanced to sequester significantly larger amounts of beyond naturally occurring levels. Reforestation and tree planting on non-forest lands are among the most mature sequestration techniques, although the latter raises food security concerns. Farmers can promote sequestration of carbon in soils through practices such as use of winter cover crops, reducing the intensity and frequency of tillage, and using compost and manure as soil amendments. Restoration/recreation of coastal wetlands and seagrass meadows increases the uptake of carbon into organic matter (blue carbon). When carbon is sequestered in soils and in organic matter such as trees, there is a risk of the carbon being re-released into the atmosphere later through changes in land use, fire, or other changes in ecosystems.


title: Climate change

text: Where energy production or -intensive heavy industries continue to produce waste , the gas can be captured and stored instead of released to the atmosphere. Although its current use is limited in scale and expensive, carbon capture and storage (CCS) may be able to play a significant role in limiting emissions by mid-century. This technique, in combination with bio-energy (BECCS) can result in net negative emissions: is drawn from the atmosphere. It remains highly uncertain whether carbon dioxide removal techniques, such as BECCS, will be able to play a large role in limiting warming to 1.5 °C. Policy decisions that rely on carbon dioxide removal increase the risk of global warming rising beyond international goals.


title: Climate change

text: Adaptation is "the process of adjustment to current or expected changes in climate and its effects". Without additional mitigation, adaptation cannot avert the risk of "severe, widespread and irreversible" impacts. More severe climate change requires more transformative adaptation, which can be prohibitively expensive. The capacity and potential for humans to adapt is unevenly distributed across different regions and populations, and developing countries generally have less. The first two decades of the 21st century saw an increase in adaptive capacity in most low- and middle-income countries with improved access to basic sanitation and electricity, but progress is slow. Many countries have implemented adaptation policies. However, there is a considerable gap between necessary and available finance.


title: Climate change

text: Adaptation to sea level rise consists of avoiding at-risk areas, learning to live with increased flooding and protection. If that fails, managed retreat may be needed. There are economic barriers for tackling dangerous heat impact. Avoiding strenuous work or having air conditioning is not possible for everybody. In agriculture, adaptation options include a switch to more sustainable diets, diversification, erosion control and genetic improvements for increased tolerance to a changing climate. Insurance allows for risk-sharing, but is often difficult to get for people on lower incomes. Education, migration and early warning systems can reduce climate vulnerability.


title: Climate change

text: Ecosystems adapt to climate change, a process that can be supported by human intervention. By increasing connectivity between ecosystems, species can migrate to more favourable climate conditions. Species can also be introduced to areas acquiring a favorable climate. Protection and restoration of natural and semi-natural areas helps build resilience, making it easier for ecosystems to adapt. Many of the actions that promote adaptation in ecosystems, also help humans adapt via ecosystem-based adaptation. For instance, restoration of natural fire regimes makes catastrophic fires less likely, and reduces human exposure. Giving rivers more space allows for more water storage in the natural system, reducing flood risk. Restored forest acts as a carbon sink, but planting trees in unsuitable regions can exacerbate climate impacts.


title: Climate change

text: There are synergies and trade-offs between adaptation and mitigation. Adaptation often offer short-term benefits, whereas mitigation has longer-term benefits. Increased use of air conditioning allows people to better cope with heat, but increases energy demand. Compact urban development may lead to reduced emissions from transport and construction. At the same time, it may increase the urban heat island effect, leading to higher temperatures and increased exposure. Increased food productivity has large benefits for both adaptation and mitigation.


title: Climate change

text: Countries that are most vulnerable to climate change have typically been responsible for a small share of global emissions. This raises questions about justice and fairness. Climate change is strongly linked to sustainable development. Limiting global warming makes it easier to achieve sustainable development goals, such as eradicating poverty and reducing inequalities. The connection is recognised in Sustainable Development Goal 13 which is to "take urgent action to combat climate change and its impacts". The goals on food, clean water and ecosystem protection have synergies with climate mitigation.


title: Climate change

text: The geopolitics of climate change is complex. It has often been framed as a free-rider problem, in which all countries benefit from mitigation done by other countries, but individual countries would lose from switching to a low-carbon economy themselves. This framing has been challenged. For instance, the benefits of a coal phase-out to public health and local environments exceed the costs in almost all regions. Furthermore, net importers of fossil fuels win economically from switching to clean energy, causing net exporters to face stranded assets: fossil fuels they cannot sell.


title: Climate change

text: A wide range of policies, regulations, and laws are being used to reduce emissions. As of 2019, carbon pricing covers about 20% of global greenhouse gas emissions. Carbon can be priced with carbon taxes and emissions trading systems. Direct global fossil fuel subsidies reached $319 billion in 2017, and $5.2 trillion when indirect costs such as air pollution are priced in. Ending these can cause a 28% reduction in global carbon emissions and a 46% reduction in air pollution deaths. Money saved on fossil subsidies could be used to support the transition to clean energy instead. More direct methods to reduce greenhouse gases include vehicle efficiency standards, renewable fuel standards, and air pollution regulations on heavy industry. Several countries require utilities to increase the share of renewables in power production.


title: Climate change

text: Policy designed through the lens of climate justice tries to address human rights issues and social inequality. For instance, wealthy nations responsible for the largest share of emissions would have to pay poorer countries to adapt. As the use of fossil fuels is reduced, jobs in the sector are being lost. To achieve a just transition, these people would need to be retrained for other jobs. Communities with many fossil fuel workers would need additional investments.


title: Climate change

text: Nearly all countries in the world are parties to the 1994 United Nations Framework Convention on Climate Change (UNFCCC). The goal of the UNFCCC is to prevent dangerous human interference with the climate system. As stated in the convention, this requires that greenhouse gas concentrations are stabilised in the atmosphere at a level where ecosystems can adapt naturally to climate change, food production is not threatened, and economic development can be sustained. The UNFCCC does not itself restrict emissions but rather provides a framework for protocols that do. Global emissions have risen since the UNFCCC was signed. Its yearly conferences are the stage of global negotiations.


title: Climate change

text: The 1997 Kyoto Protocol extended the UNFCCC and included legally binding commitments for most developed countries to limit their emissions. During the negotiations, the G77 (representing developing countries) pushed for a mandate requiring developed countries to "[take] the lead" in reducing their emissions, since developed countries contributed most to the accumulation of greenhouse gases in the atmosphere. Per-capita emissions were also still relatively low in developing countries and developing countries would need to emit more to meet their development needs.


title: Climate change

text: The 2009 Copenhagen Accord has been widely portrayed as disappointing because of its low goals, and was rejected by poorer nations including the G77. Associated parties aimed to limit the global temperature rise to below 2 °C. The Accord set the goal of sending $100 billion per year to developing countries for mitigation and adaptation by 2020, and proposed the founding of the Green Climate Fund. , the fund has failed to reach its expected target, and risks a shrinkage in its funding.


title: Climate change

text: In 2015 all UN countries negotiated the Paris Agreement, which aims to keep global warming well below 2.0 °C and contains an aspirational goal of keeping warming under . The agreement replaced the Kyoto Protocol. Unlike Kyoto, no binding emission targets were set in the Paris Agreement. Instead, a set of procedures was made binding. Countries have to regularly set ever more ambitious goals and reevaluate these goals every five years. The Paris Agreement restated that developing countries must be financially supported. , 194 states and the European Union have signed the treaty and 191 states and the EU have ratified or acceded to the agreement.


title: Climate change

text: The 1987 Montreal Protocol, an international agreement to stop emitting ozone-depleting gases, may have been more effective at curbing greenhouse gas emissions than the Kyoto Protocol specifically designed to do so. The 2016 Kigali Amendment to the Montreal Protocol aims to reduce the emissions of hydrofluorocarbons, a group of powerful greenhouse gases which served as a replacement for banned ozone-depleting gases. This made the Montreal Protocol a stronger agreement against climate change.


title: Climate change

text: In 2019, the United Kingdom parliament became the first national government to declare a climate emergency. Other countries and jurisdictions followed suit. That same year, the European Parliament declared a "climate and environmental emergency". The European Commission presented its European Green Deal with the goal of making the EU carbon-neutral by 2050. Major countries in Asia have made similar pledges: South Korea and Japan have committed to become carbon-neutral by 2050, and China by 2060. In 2021, the European Commission released its “Fit for 55” legislation package, which contains guidelines for the car industry; all new cars on the European market must be zero-emission vehicles from 2035. While India has strong incentives for renewables, it also plans a significant expansion of coal in the country.


title: Climate change

text: As of 2021, based on information from 48 national climate plans, which represent 40% of the parties to the Paris Agreement, estimated total greenhouse gas emissions will be 0.5% lower compared to 2010 levels, below the 45% or 25% reduction goals to limit global warming to 1.5 °C or 2 °C, respectively.


title: Climate change

text: Public debate about climate change has been strongly affected by climate change denial and misinformation, which originated in the United States and has since spread to other countries, particularly Canada and Australia. The actors behind climate change denial form a well-funded and relatively coordinated coalition of fossil fuel companies, industry groups, conservative think tanks, and contrarian scientists. Like the tobacco industry, the main strategy of these groups has been to manufacture doubt about scientific data and results. Many who deny, dismiss, or hold unwarranted doubt about the scientific consensus on anthropogenic climate change are labelled as "climate change skeptics", which several scientists have noted is a misnomer.


title: Climate change

text: There are different variants of climate denial: some deny that warming takes place at all, some acknowledge warming but attribute it to natural influences, and some minimise the negative impacts of climate change. Manufacturing uncertainty about the science later developed into a manufactured controversy: creating the belief that there is significant uncertainty about climate change within the scientific community in order to delay policy changes. Strategies to promote these ideas include criticism of scientific institutions, and questioning the motives of individual scientists. An echo chamber of climate-denying blogs and media has further fomented misunderstanding of climate change.


title: Climate change

text: Climate change came to international public attention in the late 1980s. Due to media coverage in the early 1990s, people often confused climate change with other environmental issues like ozone depletion. In popular culture, the climate fiction movie "The Day After Tomorrow" (2004) and the Al Gore documentary "An Inconvenient Truth" (2006) focused on climate change.


title: Climate change

text: Significant regional, gender, age and political differences exist in both public concern for, and understanding of, climate change. More highly educated people, and in some countries, women and younger people, were more likely to see climate change as a serious threat. Partisan gaps also exist in many countries, and countries with high emissions tend to be less concerned. Views on causes of climate change vary widely between countries. Concern has increased over time, to the point where in 2021 a majority of citizens in many countries express a high level of worry about climate change, or view it as a global emergency. Higher levels of worry are associated with stronger public support for policies that address climate change.


title: Climate change

text: Climate protests demand that political leaders take action to prevent climate change. They can take the form of public demonstrations, fossil fuel divestment, lawsuits and other activities. Prominent demonstrations include the School Strike for Climate. In this initiative, young people across the globe have been protesting since 2018 by skipping school on Fridays, inspired by Swedish teenager Greta Thunberg. Mass civil disobedience actions by groups like Extinction Rebellion have protested by disrupting roads and public transport. Litigation is increasingly used as a tool to strengthen climate action from public institutions and companies. Activists also initiate lawsuits which target governments and demand that they take ambitious action or enforce existing laws on climate change. Lawsuits against fossil-fuel companies generally seek compensation for loss and damage.


title: Climate change

text: In the 1820s, Joseph Fourier proposed the greenhouse effect to explain why Earth's temperature was higher than the sun's energy alone could explain. Earth's atmosphere is transparent to sunlight, so sunlight reaches the surface where it is converted to heat. However, the atmosphere is not transparent to heat radiating from the surface, and captures some of that heat, which in turn warms the planet.


title: Climate change

text: In 1856 Eunice Newton Foote demonstrated that the warming effect of the sun is greater for air with water vapour than for dry air, and that the effect is even greater with carbon dioxide (). She concluded that "An atmosphere of that gas would give to our earth a high temperature..."


title: Climate change

text: Starting in 1859, John Tyndall established that nitrogen and oxygen—together totaling 99% of dry air—are transparent to radiated heat. However, water vapour and gases such as methane and carbon dioxide absorb radiated heat and re-radiate that heat into the atmosphere. Tyndall proposed that changes in the concentrations of these gases may have caused climatic changes in the past, including ice ages.


title: Climate change

text: Svante Arrhenius noted that water vapour in air continuously varied, but the concentration in air was influenced by long-term geological processes. Warming from increased levels would increase the amount of water vapour, amplifying warming in a positive feedback loop. In 1896, he published the first climate model of its kind, projecting that halving levels could have produced a drop in temperature initiating an ice age. Arrhenius calculated the temperature increase expected from doubling to be around 5–6 °C. Other scientists were initially skeptical and believed that the greenhouse effect was saturated so that adding more would make no difference, and that the climate would be self-regulating. Beginning in 1938, Guy Stewart Callendar published evidence that climate was warming and levels were rising, but his calculations met the same objections.


title: Climate change

text: In the 1950s, Gilbert Plass created a detailed computer model that included different atmospheric layers and the infrared spectrum. This model predicted that increasing levels would cause warming. Around the same time, Hans Suess found evidence that levels had been rising, and Roger Revelle showed that the oceans would not absorb the increase. The two scientists subsequently helped Charles Keeling to begin a record of continued increase, which has been termed the "Keeling Curve". Scientists alerted the public, and the dangers were highlighted at James Hansen's 1988 Congressional testimony. The Intergovernmental Panel on Climate Change (IPCC), set up in 1988 to provide formal advice to the world's governments, spurred interdisciplinary research. As part of the IPCC reports, scientists assess the scientific discussion that takes place in peer-reviewed journal articles.


title: Climate change

text: There is a near-complete scientific consensus that the climate is warming and that this is caused by human activities. As of 2019, agreement in recent literature reached over 99%. No scientific body of national or international standing disagrees with this view. Consensus has further developed that some form of action should be taken to protect people against the impacts of climate change. National science academies have called on world leaders to cut global emissions. The 2021 IPCC Assessment Report stated that it is "unequivocal" that climate change is caused by humans.


title: Chordate

text: A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adulthood stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These five synapomorphies include a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal slits, and a post-anal tail. The name “chordate” comes from the first of these synapomorphies, the notochord, which plays a significant role in chordate structure and movement. Chordates are also bilaterally symmetric, have a coelom, possess a circulatory system, and exhibit metameric segmentation.


title: Chordate

text: In addition to the morphological characteristics used to define chordates, analysis of genome sequences has identified two conserved signature indels (CSIs) in their proteins: cyclophilin-like protein and mitochondrial inner membrane protease ATP23, which are exclusively shared by all vertebrates, tunicates and cephalochordates. These CSIs provide molecular means to reliably distinguish chordates from all other metazoan.


title: Chordate

text: Chordates are divided into three subphyla: Craniata (fish, amphibians, reptiles, birds, and mammals); Tunicata or Urochordata (sea squirts, salps); and Cephalochordata (which includes lancelets). The Craniata and Tunicata compose the clade Olfactores, which is sister to Cephalochordata. (See diagram under Phylogeny.) Extinct taxa such as Vetulicolia and Conodonta are Chordata, but their internal placement is less certain. Hemichordata (which includes the acorn worms) was previously considered a fourth chordate subphylum, but now is treated as a separate phylum: hemichordates and Echinodermata form the Ambulacraria, the sister phylum of the Chordates. The Chordata and Ambulacraria, together and possibly with the Xenacoelomorpha, form the superphylum Deuterostomia.


title: Chordate

text: Chordate fossils have been found from as early as the Cambrian explosion, 539 million years ago. Cladistically (phylogenetically), vertebrates – chordates with the notochord replaced by a vertebral column during development – are a subgroup of the clade Craniata, which consists of chordates with a skull. Of the more than 65,000 living species of chordates, about half are ray-finned fishes that are members of the class Actinopterygii and the vast majority of the rest are tetrapods (mostly birds and mammals).


title: Chordate

text: Chordates form a phylum of animals that are defined by having at some stage in their lives all of the following anatomical features:


title: Chordate

text: There are soft constraints that separate chordates from other biological lineages, but are not part of the formal definition:


title: Chordate

text: The following schema is from the 2015 edition of "Vertebrate Palaeontology". The invertebrate chordate classes are from "Fishes of the World". While it is structured so as to reflect evolutionary relationships (similar to a cladogram), it also retains the traditional ranks used in Linnaean taxonomy.


title: Chordate

text: Cephalochordates, one of the three subdivisions of chordates, are small, "vaguely fish-shaped" animals that lack brains, clearly defined heads and specialized sense organs. These burrowing filter-feeders compose the earliest-branching chordate sub-phylum.


title: Chordate

text: Most tunicates appear as adults in two major forms, known as "sea squirts" and salps, both of which are soft-bodied filter-feeders that lack the standard features of chordates. Sea squirts are sessile and consist mainly of water pumps and filter-feeding apparatus; salps float in mid-water, feeding on plankton, and have a two-generation cycle in which one generation is solitary and the next forms chain-like colonies. However, all tunicate larvae have the standard chordate features, including long, tadpole-like tails; they also have rudimentary brains, light sensors and tilt sensors. The third main group of tunicates, Appendicularia (also known as Larvacea), retain tadpole-like shapes and active swimming all their lives, and were for a long time regarded as larvae of sea squirts or salps. The etymology of the term Urochordata (Balfour 1881) is from the ancient Greek οὐρά (oura, "tail") + Latin chorda ("cord"), because the notochord is only found in the tail. The term Tunicata (Lamarck 1816) is recognised as having precedence and is now more commonly used.


title: Chordate

text: Craniates all have distinct skulls. They include the hagfish, which have no vertebrae. Michael J. Benton commented that "craniates are characterized by their heads, just as chordates, or possibly all deuterostomes, are by their tails".


title: Chordate

text: Most craniates are vertebrates, in which the notochord is replaced by the vertebral column. These consist of a series of bony or cartilaginous cylindrical vertebrae, generally with neural arches that protect the spinal cord, and with projections that link the vertebrae. However hagfish have incomplete braincases and no vertebrae, and are therefore not regarded as vertebrates,


title: Chordate

text: but as members of the craniates, the group from which vertebrates are thought to have evolved. However the cladistic exclusion of hagfish from the vertebrates is controversial, as they may be degenerate vertebrates who have lost their vertebral columns.


title: Chordate

text: The position of lampreys is ambiguous. They have complete braincases and rudimentary vertebrae, and therefore may be regarded as vertebrates and true fish. However, molecular phylogenetics, which uses biochemical features to classify organisms, has produced both results that group them with vertebrates and others that group them with hagfish. If lampreys are more closely related to the hagfish than the other vertebrates, this would suggest that they form a clade, which has been named the Cyclostomata.


title: Chordate

text: There is still much ongoing differential (DNA sequence based) comparison research that is trying to separate out the simplest forms of chordates. As some lineages of the 90% of species that lack a backbone or notochord might have lost these structures over time, this complicates the classification of chordates. Some chordate lineages may only be found by DNA analysis, when there is no physical trace of any chordate-like structures.


title: Chordate

text: Attempts to work out the evolutionary relationships of the chordates have produced several hypotheses. The current consensus is that chordates are monophyletic, meaning that the Chordata include all and only the descendants of a single common ancestor, which is itself a chordate, and that craniates' nearest relatives are tunicates. Recent identification of two conserved signature indels (CSIs) in the proteins cyclophilin-like protein and mitochondrial inner membrane protease ATP23, which are exclusively shared by all vertebrates, tunicates and cephalochordates also provide strong evidence of the monophyly of Chordata.


title: Chordate

text: All of the earliest chordate fossils have been found in the Early Cambrian Chengjiang fauna, and include two species that are regarded as fish, which implies that they are vertebrates. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a reasonable prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial.


title: Chordate

text: It has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce evolutionary "family trees" shows that many of the traditional classes are paraphyletic.


title: Chordate

text: While this has been well known since the 19th century, an insistence on only monophyletic taxa has resulted in vertebrate classification being in a state of flux.


title: Chordate

text: The majority of animals more complex than jellyfish and other Cnidarians are split into two groups, the protostomes and deuterostomes, the latter of which contains chordates. It seems very likely the "Kimberella" was a member of the protostomes. If so, this means the protostome and deuterostome lineages must have split some time before "Kimberella" appeared—at least , and hence well before the start of the Cambrian . The Ediacaran fossil "Ernietta", from about , may represent a deuterostome animal.


title: Chordate

text: Fossils of one major deuterostome group, the echinoderms (whose modern members include starfish, sea urchins and crinoids), are quite common from the start of the Cambrian, . The Mid Cambrian fossil "Rhabdotubus johanssoni" has been interpreted as a pterobranch hemichordate. Opinions differ about whether the Chengjiang fauna fossil "Yunnanozoon", from the earlier Cambrian, was a hemichordate or chordate. Another fossil, "Haikouella lanceolata", also from the Chengjiang fauna, is interpreted as a chordate and possibly a craniate, as it shows signs of a heart, arteries, gill filaments, a tail, a neural chord with a brain at the front end, and possibly eyes—although it also had short tentacles round its mouth. "Haikouichthys" and "Myllokunmingia", also from the Chengjiang fauna, are regarded as fish. "Pikaia", discovered much earlier (1911) but from the Mid Cambrian Burgess Shale (505 Ma), is also regarded as a primitive chordate. On the other hand, fossils of early chordates are very rare, since invertebrate chordates have no bones or teeth, and only one has been reported for the rest of the Cambrian.


title: Chordate

text: The evolutionary relationships between the chordate groups and between chordates as a whole and their closest deuterostome relatives have been debated since 1890. Studies based on anatomical, embryological, and paleontological data have produced different "family trees". Some closely linked chordates and hemichordates, but that idea is now rejected. Combining such analyses with data from a small set of ribosome RNA genes eliminated some older ideas, but opened up the possibility that tunicates (urochordates) are "basal deuterostomes", surviving members of the group from which echinoderms, hemichordates and chordates evolved. Some researchers believe that, within the chordates, craniates are most closely related to cephalochordates, but there are also reasons for regarding tunicates (urochordates) as craniates' closest relatives.


title: Chordate

text: Since early chordates have left a poor fossil record, attempts have been made to calculate the key dates in their evolution by molecular phylogenetics techniques—by analyzing biochemical differences, mainly in RNA. One such study suggested that deuterostomes arose before and the earliest chordates around . However, molecular estimates of dates often disagree with each other and with the fossil record, and their assumption that the molecular clock runs at a known constant rate has been challenged.


title: Chordate

text: Traditionally, Cephalochordata and Craniata were grouped into the proposed clade "Euchordata", which would have been the sister group to Tunicata/Urochordata. More recently, Cephalochordata has been thought of as a sister group to the "Olfactores", which includes the craniates and tunicates. The matter is not yet settled.


title: Chordate

text: A specific relationship between Vertebrates and Tunicates is also strongly supported by two CSIs found in the proteins predicted exosome complex RRP44 and serine palmitoyltransferase, that are exclusively shared by species from these two subphyla but not Cephalochordates, indicating Vertebrates are more closely related to Tunicates than Cephalochordates.


title: Chordate

text: Phylogenetic tree of the chordate phylum. Lines of the cladogram show probable evolutionary relationships between both extinct taxa, which are denoted with a dagger (†), and extant taxa. Relatives of vertebrates are invertebrates. The positions (relationships) of the lancelets, tunicates, and craniates/vertebrates are based on the following studies:


title: Chordate

text: The closest relatives of the Chordates are the Hemichordates and Echinodermata, which together form the Ambulacraria.


title: Chordate

text: Hemichordates ("half chordates") have some features similar to those of chordates: branchial openings that open into the pharynx and look rather like gill slits; stomochords, similar in composition to notochords, but running in a circle round the "collar", which is ahead of the mouth; and a dorsal nerve cord—but also a smaller ventral nerve cord.


title: Chordate

text: There are two living groups of hemichordates. The solitary enteropneusts, commonly known as "acorn worms", have long proboscises and worm-like bodies with up to 200 branchial slits, are up to long, and burrow though seafloor sediments. Pterobranchs are colonial animals, often less than long individually, whose dwellings are interconnected. Each filter feeds by means of a pair of branched tentacles, and has a short, shield-shaped proboscis. The extinct graptolites, colonial animals whose fossils look like tiny hacksaw blades, lived in tubes similar to those of pterobranchs.


title: Chordate

text: Echinoderms differ from chordates and their other relatives in three conspicuous ways: they possess bilateral symmetry only as larvae – in adulthood they have radial symmetry, meaning that their body pattern is shaped like a wheel; they have tube feet; and their bodies are supported by skeletons made of calcite, a material not used by chordates. Their hard, calcified shells keep their bodies well protected from the environment, and these skeletons enclose their bodies, but are also covered by thin skins. The feet are powered by another unique feature of echinoderms, a water vascular system of canals that also functions as a "lung" and surrounded by muscles that act as pumps. Crinoids look rather like flowers, and use their feather-like arms to filter food particles out of the water; most live anchored to rocks, but a few can move very slowly. Other echinoderms are mobile and take a variety of body shapes, for example starfish, sea urchins and sea cucumbers.


title: Chordate

text: Although the name Chordata is attributed to William Bateson (1885), it was already in prevalent use by 1880. Ernst Haeckel described a taxon comprising tunicates, cephalochordates, and vertebrates in 1866. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization.


title: Calculator

text: An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics.


title: Calculator

text: The first solid-state electronic calculator was created in the early 1960s. Pocket-sized devices became available in the 1970s, especially after the Intel 4004, the first microprocessor, was developed by Intel for the Japanese calculator company Busicom.


title: Calculator

text: Modern electronic calculators vary from cheap, give-away, credit-card-sized models to sturdy desktop models with built-in printers. They became popular in the mid-1970s as the incorporation of integrated circuits reduced their size and cost. By the end of that decade, prices had dropped to the point where a basic calculator was affordable to most and they became common in schools.


title: Calculator

text: Computer operating systems as far back as early Unix have included interactive calculator programs such as dc and hoc, and interactive BASIC could be used to do calculations on most 1970s and 1980s home computers. Calculator functions are included in most personal digital assistant (PDA) type devices.


title: Calculator

text: In addition to general purpose calculators, there are those designed for specific markets. For example, there are scientific calculators which include trigonometric and statistical calculations. Some calculators even have the ability to do computer algebra. Graphing calculators can be used to graph functions defined on the real line, or higher-dimensional Euclidean space. , basic calculators cost little, but scientific and graphing models tend to cost more.


title: Calculator

text: With the very wide availability of smartphones, tablet computers and personal computers, dedicated hardware calculators, while still widely used, are less common than they once were. In 1986, calculators still represented an estimated 41% of the world's general-purpose hardware capacity to compute information. By 2007, this had diminished to less than 0.05%.


title: Calculator

text: Electronic calculators contain a keyboard with buttons for digits and arithmetical operations; some even contain "00" and "000" buttons to make larger or smaller numbers easier to enter. Most basic calculators assign only one digit or operation on each button; however, in more specific calculators, a button can perform multi-function working with key combinations.


title: Calculator

text: Calculators usually have liquid-crystal displays (LCD) as output in place of historical light-emitting diode (LED) displays and vacuum fluorescent displays (VFD); details are provided in the section "Technical improvements".


title: Calculator

text: Large-sized figures are often used to improve readability; while using decimal separator (usually a point rather than a comma) instead of or in addition to vulgar fractions. Various symbols for function commands may also be shown on the display. Fractions such as are displayed as decimal approximations, for example rounded to . Also, some fractions (such as , which is ; to 14 significant figures) can be difficult to recognize in decimal form; as a result, many scientific calculators are able to work in vulgar fractions or mixed numbers.


title: Calculator

text: Calculators also have the ability to store numbers into computer memory. Basic calculators usually store only one number at a time; more specific types are able to store many numbers represented in variables. The variables can also be used for constructing formulas. Some models have the ability to extend memory capacity to store more numbers; the extended memory address is termed an array index.


title: Calculator

text: Power sources of calculators are batteries, solar cells or mains electricity (for old models), turning on with a switch or button. Some models even have no turn-off button but they provide some way to put off (for example, leaving no operation for a moment, covering solar cell exposure, or closing their lid). Crank-powered calculators were also common in the early computer era.


title: Calculator

text: The following keys are common to most pocket calculators. While the arrangement of the digits is standard, the positions of other keys vary from model to model; the illustration is an example.


title: Calculator

text: Clock rate of a processor chip refers to the frequency at which the central processing unit (CPU) is running. It is used as an indicator of the processor's speed, and is measured in "clock cycles per second" or hertz (Hz). For basic calculators, the speed can vary from a few hundred hertz to the kilohertz range.


title: Calculator

text: Most pocket calculators do all their calculations in binary-coded decimal (BCD) rather than binary. BCD is common in electronic systems where a numeric value is to be displayed, especially in systems consisting solely of digital logic, and not containing a microprocessor. By employing BCD, the manipulation of numerical data for display can be greatly simplified by treating each digit as a separate single sub-circuit. This matches much more closely the physical reality of display hardware—a designer might choose to use a series of separate identical seven-segment displays to build a metering circuit, for example. If the numeric quantity were stored and manipulated as pure binary, interfacing to such a display would require complex circuitry. Therefore, in cases where the calculations are relatively simple, working throughout with BCD can lead to a simpler overall system than converting to and from binary. (For example, CDs keep the track number in BCD, limiting them to 99 tracks.)


title: Calculator

text: The same argument applies when hardware of this type uses an embedded microcontroller or other small processor. Often, smaller code results when representing numbers internally in BCD format, since a conversion from or to binary representation can be expensive on such limited processors. For these applications, some small processors feature BCD arithmetic modes, which assist when writing routines that manipulate BCD quantities.


title: Calculator

text: Where calculators have added functions (such as square root, or trigonometric functions), software algorithms are required to produce high precision results. Sometimes significant design effort is needed to fit all the desired functions in the limited memory space available in the calculator chip, with acceptable calculation time.


title: Calculator

text: The fundamental difference between a calculator and computer is that a computer can be programmed in a way that allows the program to take different branches according to intermediate results, while calculators are pre-designed with specific functions (such as addition, multiplication, and logarithms) built in. The distinction is not clear-cut: some devices classed as programmable calculators have programming functions, sometimes with support for programming languages (such as RPL or TI-BASIC).


title: Calculator

text: For instance, instead of a hardware multiplier, a calculator might implement floating point mathematics with code in read-only memory (ROM), and compute trigonometric functions with the CORDIC algorithm because CORDIC does not require much multiplication. Bit serial logic designs are more common in calculators whereas bit parallel designs dominate general-purpose computers, because a bit serial design minimizes chip complexity, but takes many more clock cycles. This distinction blurs with high-end calculators, which use processor chips associated with computer and embedded systems design, more so the Z80, MC68000, and ARM architectures, and some custom designs specialized for the calculator market.


title: Calculator

text: The first known tools used to aid arithmetic calculations were: bones (used to tally items), pebbles, and counting boards, and the abacus, known to have been used by Sumerians and Egyptians before 2000 BC. Except for the Antikythera mechanism (an "out of the time" astronomical device), development of computing tools arrived near the start of the 17th century: the geometric-military compass (by Galileo), logarithms and Napier bones (by Napier), and the slide rule (by Edmund Gunter).


title: Calculator

text: In 1642, the Renaissance saw the invention of the mechanical calculator (by Wilhelm Schickard and several decades later Blaise Pascal), a device that was at times somewhat over-promoted as being able to perform all four arithmetic operations with minimal human intervention. Pascal's calculator could add and subtract two numbers directly and thus, if the tedium could be borne, multiply and divide by repetition. Schickard's machine, constructed several decades earlier, used a clever set of mechanised multiplication tables to ease the process of multiplication and division with the adding machine as a means of completing this operation. There is a debate about whether Pascal or Shickard should be credited as the known inventor of a calculating machine due to the differences (like the different aims) of both inventions. Schickard and Pascal were followed by Gottfried Leibniz who spent forty years designing a four-operation mechanical calculator, the stepped reckoner, inventing in the process his leibniz wheel, but who couldn't design a fully operational machine. There were also five unsuccessful attempts to design a calculating clock in the 17th century.


title: Calculator

text: The 18th century saw the arrival of some notable improvements, first by Poleni with the first fully functional calculating clock and four-operation machine, but these machines were almost always "one of a kind". Luigi Torchi invented the first direct multiplication machine in 1834: this was also the second key-driven machine in the world, following that of James White (1822). It was not until the 19th century and the Industrial Revolution that real developments began to occur. Although machines capable of performing all four arithmetic functions existed prior to the 19th century, the refinement of manufacturing and fabrication processes during the eve of the industrial revolution made large scale production of more compact and modern units possible. The Arithmometer, invented in 1820 as a four-operation mechanical calculator, was released to production in 1851 as an adding machine and became the first commercially successful unit; forty years later, by 1890, about 2,500 arithmometers had been sold plus a few hundreds more from two arithmometer clone makers (Burkhardt, Germany, 1878 and Layton, UK, 1883) and Felt and Tarrant, the only other competitor in true commercial production, had sold 100 comptometers.


title: Calculator

text: It wasn't until 1902 that the familiar push-button user interface was developed, with the introduction of the Dalton Adding Machine, developed by James L. Dalton in the United States.


title: Calculator

text: In 1921, Edith Clarke invented the "Clarke calculator", a simple graph-based calculator for solving line equations involving hyperbolic functions. This allowed electrical engineers to simplify calculations for inductance and capacitance in power transmission lines.


title: Calculator

text: The Curta calculator was developed in 1948 and, although costly, became popular for its portability. This purely mechanical hand-held device could do addition, subtraction, multiplication and division. By the early 1970s electronic pocket calculators ended manufacture of mechanical calculators, although the Curta remains a popular collectable item.


title: Calculator

text: The first mainframe computers, using firstly vacuum tubes and later transistors in the logic circuits, appeared in the 1940s and 1950s. This technology was to provide a stepping stone to the development of electronic calculators.


title: Calculator

text: The Casio Computer Company, in Japan, released the Model "14-A" calculator in 1957, which was the world's first all-electric (relatively) compact calculator. It did not use electronic logic but was based on relay technology, and was built into a desk.


title: Calculator

text: In October 1961, the world's first "all-electronic desktop" calculator, the British Bell Punch/Sumlock Comptometer ANITA (A New Inspiration To Arithmetic/Accounting) was announced. This machine used vacuum tubes, cold-cathode tubes and Dekatrons in its circuits, with 12 cold-cathode "Nixie" tubes for its display. Two models were displayed, the Mk VII for continental Europe and the Mk VIII for Britain and the rest of the world, both for delivery from early 1962. The Mk VII was a slightly earlier design with a more complicated mode of multiplication, and was soon dropped in favour of the simpler Mark VIII. The ANITA had a full keyboard, similar to mechanical comptometers of the time, a feature that was unique to it and the later Sharp CS-10A among electronic calculators. The ANITA weighed roughly due to its large tube system. Bell Punch had been producing key-driven mechanical calculators of the comptometer type under the names "Plus" and "Sumlock", and had realised in the mid-1950s that the future of calculators lay in electronics. They employed the young graduate Norbert Kitz, who had worked on the early British Pilot ACE computer project, to lead the development. The ANITA sold well since it was the only electronic desktop calculator available, and was silent and quick.


title: Calculator

text: The tube technology of the ANITA was superseded in June 1963 by the U.S. manufactured Friden EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a cathode ray tube (CRT), and introduced Reverse Polish Notation (RPN) to the calculator market for a price of $2200, which was about three times the cost of an electromechanical calculator of the time. Like Bell Punch, Friden was a manufacturer of mechanical calculators that had decided that the future lay in electronics. In 1964 more all-transistor electronic calculators were introduced: Sharp introduced the CS-10A, which weighed and cost 500,000 yen ($), and Industria Macchine Elettroniche of Italy introduced the IME 84, to which several extra keyboard and display units could be connected so that several people could make use of it (but apparently not at the same time). The Victor 3900 was the first to use integrated circuits in place of individual transistors, but production problems delayed sales until 1966.


title: Calculator

text: There followed a series of electronic calculator models from these and other manufacturers, including Canon, Mathatronics, Olivetti, SCM (Smith-Corona-Marchant), Sony, Toshiba, and Wang. The early calculators used hundreds of germanium transistors, which were cheaper than silicon transistors, on multiple circuit boards. Display types used were CRT, cold-cathode Nixie tubes, and filament lamps. Memory technology was usually based on the delay-line memory or the magnetic-core memory, though the Toshiba "Toscal" BC-1411 appears to have used an early form of dynamic RAM built from discrete components. Already there was a desire for smaller and less power-hungry machines.


title: Calculator

text: Bulgaria's ELKA 6521, introduced in 1965, was developed by the Central Institute for Calculation Technologies and built at the Elektronika factory in Sofia. The name derives from "ELektronen KAlkulator", and it weighed around . It is the first calculator in the world which includes the square root function. Later that same year were released the ELKA 22 (with a luminescent display) and the ELKA 25, with an in-built printer. Several other models were developed until the first pocket model, the ELKA 101, was released in 1974. The writing on it was in Roman script, and it was exported to western countries.


title: Calculator

text: The first desktop "programmable calculators" were produced in the mid-1960s. They included the Mathatronics Mathatron (1964) and the Olivetti Programma 101 (late 1965) which were solid-state, desktop, printing, floating point, algebraic entry, programmable, stored-program electronic calculators. Both could be programmed by the end user and print out their results. The Programma 101 saw much wider distribution and had the added feature of offline storage of programs via magnetic cards.


title: Calculator

text: Another early programmable desktop calculator (and maybe the first Japanese one) was the Casio (AL-1000) produced in 1967. It featured a nixie tubes display and had transistor electronics and ferrite core memory.


title: Calculator

text: The "Monroe Epic" programmable calculator came on the market in 1967. A large, printing, desk-top unit, with an attached floor-standing logic tower, it could be programmed to perform many computer-like functions. However, the only "branch" instruction was an implied unconditional branch (GOTO) at the end of the operation stack, returning the program to its starting instruction. Thus, it was not possible to include any conditional branch (IF-THEN-ELSE) logic. During this era, the absence of the conditional branch was sometimes used to distinguish a programmable calculator from a computer.


title: Calculator

text: The first Soviet programmable desktop calculator ISKRA 123, powered by the power grid, was released at the start of the 1970s.


title: Calculator

text: The electronic calculators of the mid-1960s were large and heavy desktop machines due to their use of hundreds of transistors on several circuit boards with a large power consumption that required an AC power supply. There were great efforts to put the logic required for a calculator into fewer and fewer integrated circuits (chips) and calculator electronics was one of the leading edges of semiconductor development. U.S. semiconductor manufacturers led the world in large scale integration (LSI) semiconductor development, squeezing more and more functions into individual integrated circuits. This led to alliances between Japanese calculator manufacturers and U.S. semiconductor companies: Canon Inc. with Texas Instruments, Hayakawa Electric (later renamed Sharp Corporation) with North-American Rockwell Microelectronics (later renamed Rockwell International), Busicom with Mostek and Intel, and General Instrument with Sanyo.


title: Calculator

text: By 1970, a calculator could be made using just a few chips of low power consumption, allowing portable models powered from rechargeable batteries. The first handheld calculator was a 1967 prototype called Cal Tech, whose development was led by Jack Kilby at Texas Instruments in a research project to produce a portable calculator. It could add, multiply, subtract, and divide, and its output device was a paper tape. As a result of the "Cal-Tech" project, Texas Instruments was granted master patents on portable calculators.


title: Calculator

text: The first commercially produced portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the Sanyo ICC-0081 "Mini Calculator", the Canon Pocketronic, and the Sharp QT-8B "micro Compet". The Canon Pocketronic was a development from the "Cal-Tech" project. It had no traditional display; numerical output was on thermal paper tape.


title: Calculator

text: Sharp put in great efforts in size and power reduction and introduced in January 1971 the Sharp EL-8, also marketed as the Facit 1111, which was close to being a pocket calculator. It weighed 1.59 pounds (721 grams), had a vacuum fluorescent display, rechargeable NiCad batteries, and initially sold for US$395.


title: Calculator

text: However, integrated circuit development efforts culminated in early 1971 with the introduction of the first "calculator on a chip", the MK6010 by Mostek, followed by Texas Instruments later in the year. Although these early hand-held calculators were very costly, these advances in electronics, together with developments in display technology (such as the vacuum fluorescent display, LED, and LCD), led within a few years to the cheap pocket calculator available to all.


title: Calculator

text: In 1971, Pico Electronics and General Instrument also introduced their first collaboration in ICs, a full single chip calculator IC for the Monroe Royal Digital III calculator. Pico was a spinout by five GI design engineers whose vision was to create single chip calculator ICs. Pico and GI went on to have significant success in the burgeoning handheld calculator market.


title: Calculator

text: The first truly pocket-sized electronic calculator was the Busicom LE-120A "HANDY", which was marketed early in 1971. Made in Japan, this was also the first calculator to use an LED display, the first hand-held calculator to use a single integrated circuit (then proclaimed as a "calculator on a chip"), the Mostek MK6010, and the first electronic calculator to run off replaceable batteries. Using four AA-size cells the LE-120A measures .


title: Calculator

text: The first European-made pocket-sized calculator, DB 800 was made in May 1971 by Digitron in Buje, Croatia (former Yugoslavia) with four functions and an eight-digit display and special characters for a negative number and a warning that the calculation has too many digits to display.


title: Calculator

text: The first American-made pocket-sized calculator, the Bowmar 901B (popularly termed "The Bowmar Brain"), measuring , came out in the Autumn of 1971, with four functions and an eight-digit red LED display, for , while in August 1972 the four-function Sinclair Executive became the first slimline pocket calculator measuring and weighing . It retailed for around £79 ( at the time). By the end of the decade, similar calculators were priced less than £5 ($). Following protracted development over the course of two years including a botched partnership with Texas Instruments, Eldorado Electrodata released five pocket calculators in 1972. One called the Touch Magic was "no bigger than a pack of cigarettes" according to "Administrative Management".


title: Calculator

text: The first Soviet Union made pocket-sized calculator, the "Elektronika B3-04" was developed by the end of 1973 and sold at the start of 1974.


title: Calculator

text: One of the first low-cost calculators was the Sinclair Cambridge, launched in August 1973. It retailed for £29.95 ($), or £5 ($) less in kit form. The Sinclair calculators were successful because they were far cheaper than the competition; however, their design led to slow and inaccurate computations of transcendental functions.


title: Calculator

text: Meanwhile, Hewlett-Packard (HP) had been developing a pocket calculator. Launched in early 1972, it was unlike the other basic four-function pocket calculators then available in that it was the first pocket calculator with "scientific" functions that could replace a slide rule. The $395 HP-35, along with nearly all later HP engineering calculators, uses reverse Polish notation (RPN), also called postfix notation. A calculation like "8 plus 5" is, using RPN, performed by pressing , , , and ; instead of the algebraic infix notation: , , , . It had 35 buttons and was based on Mostek Mk6020 chip.


title: Calculator

text: In 1973, Texas Instruments (TI) introduced the SR-10, ("SR" signifying slide rule) an "algebraic entry" pocket calculator using scientific notation for $150. Shortly after the SR-11 featured an added key for entering pi (π). It was followed the next year by the SR-50 which added log and trig functions to compete with the HP-35, and in 1977 the mass-marketed TI-30 line which is still produced.


title: Calculator

text: In 1978, a new company, Calculated Industries arose which focused on specialized markets. Their first calculator, the Loan Arranger (1978) was a pocket calculator marketed to the Real Estate industry with preprogrammed functions to simplify the process of calculating payments and future values. In 1985, CI launched a calculator for the construction industry called the Construction Master which came preprogrammed with common construction calculations (such as angles, stairs, roofing math, pitch, rise, run, and feet-inch fraction conversions). This would be the first in a line of construction related calculators.


title: Calculator

text: The first programmable pocket calculator was the HP-65, in 1974; it had a capacity of 100 instructions, and could store and retrieve programs with a built-in magnetic card reader. Two years later the HP-25C introduced "continuous memory", i.e., programs and data were retained in CMOS memory during power-off. In 1979, HP released the first "alphanumeric", programmable, "expandable" calculator, the HP-41C. It could be expanded with random-access memory (RAM, for memory) and read-only memory (ROM, for software) modules, and peripherals like bar code readers, microcassette and floppy disk drives, paper-roll thermal printers, and miscellaneous communication interfaces (RS-232, HP-IL, HP-IB).


title: Calculator

text: The first Soviet pocket battery-powered programmable calculator, Elektronika "B3-21", was developed by the end of 1976 and released at the start of 1977. The successor of B3-21, the Elektronika B3-34 wasn't backward compatible with B3-21, even if it kept the reverse Polish notation (RPN). Thus B3-34 defined a new command set, which later was used in a series of later programmable Soviet calculators. Despite very limited abilities (98 bytes of instruction memory and about 19 stack and addressable registers), people managed to write all kinds of programs for them, including adventure games and libraries of calculus-related functions for engineers. Hundreds, perhaps thousands, of programs were written for these machines, from practical scientific and business software, which were used in real-life offices and labs, to fun games for children. The Elektronika MK-52 calculator (using the extended B3-34 command set, and featuring internal EEPROM memory for storing programs and external interface for EEPROM cards and other periphery) was used in Soviet spacecraft program (for Soyuz TM-7 flight) as a backup of the board computer.


title: Calculator

text: This series of calculators was also noted for a large number of highly counter-intuitive mysterious undocumented features, somewhat similar to "synthetic programming" of the American HP-41, which were exploited by applying normal arithmetic operations to error messages, jumping to nonexistent addresses and other methods. A number of respected monthly publications, including the popular science magazine "Nauka i Zhizn" ("Наука и жизнь", "Science and Life"), featured special columns, dedicated to optimization methods for calculator programmers and updates on undocumented features for hackers, which grew into a whole esoteric science with many branches, named "yeggogology" ("еггогология"). The error messages on those calculators appear as a Russian word "YEGGOG" ("ЕГГОГ") which, unsurprisingly, is translated to "Error".


title: Calculator

text: A similar hacker culture in the USA revolved around the HP-41, which was also noted for a large number of undocumented features and was much more powerful than B3-34.


title: Calculator

text: Through the 1970s the hand-held electronic calculator underwent rapid development. The red LED and blue/green vacuum fluorescent displays consumed a lot of power and the calculators either had a short battery life (often measured in hours, so rechargeable nickel-cadmium batteries were common) or were large so that they could take larger, higher capacity batteries. In the early 1970s liquid-crystal displays (LCDs) were in their infancy and there was a great deal of concern that they only had a short operating lifetime. Busicom introduced the Busicom "LE-120A "HANDY"" calculator, the first pocket-sized calculator and the first with an LED display, and announced the Busicom "LC" with LCD. However, there were problems with this display and the calculator never went on sale. The first successful calculators with LCDs were manufactured by Rockwell International and sold from 1972 by other companies under such names as: Dataking "LC-800", Harden "DT/12", Ibico "086", Lloyds "40", Lloyds "100", Prismatic "500" (a.k.a. "P500"), Rapid Data "Rapidman 1208LC". The LCDs were an early form using the "Dynamic Scattering Mode DSM" with the numbers appearing as bright against a dark background. To present a high-contrast display these models illuminated the LCD using a filament lamp and solid plastic light guide, which negated the low power consumption of the display. These models appear to have been sold only for a year or two.


title: Calculator

text: A more successful series of calculators using a reflective DSM-LCD was launched in 1972 by Sharp Inc with the Sharp "EL-805", which was a slim pocket calculator. This, and another few similar models, used Sharp's "Calculator On Substrate" (COS) technology. An extension of one glass plate needed for the liquid crystal display was used as a substrate to mount the needed chips based on a new hybrid technology. The COS technology may have been too costly since it was only used in a few models before Sharp reverted to conventional circuit boards.


title: Calculator

text: In the mid-1970s the first calculators appeared with field-effect, "twisted nematic" (TN) LCDs with dark numerals against a grey background, though the early ones often had a yellow filter over them to cut out damaging ultraviolet rays. The advantage of LCDs is that they are passive light modulators reflecting light, which require much less power than light-emitting displays such as LEDs or VFDs. This led the way to the first credit-card-sized calculators, such as the Casio "Mini Card LC-78" of 1978, which could run for months of normal use on button cells.


title: Calculator

text: There were also improvements to the electronics inside the calculators. All of the logic functions of a calculator had been squeezed into the first "calculator on a chip" integrated circuits (ICs) in 1971, but this was leading edge technology of the time and yields were low and costs were high. Many calculators continued to use two or more ICs, especially the scientific and the programmable ones, into the late 1970s.


title: Calculator

text: The power consumption of the integrated circuits was also reduced, especially with the introduction of CMOS technology. Appearing in the Sharp "EL-801" in 1972, the transistors in the logic cells of CMOS ICs only used any appreciable power when they changed state. The LED and VFD displays often required added driver transistors or ICs, whereas the LCDs were more amenable to being driven directly by the calculator IC itself.


title: Calculator

text: With this low power consumption came the possibility of using solar cells as the power source, realised around 1978 by calculators such as the Royal "Solar 1", Sharp "EL-8026", and Teal "Photon".


title: Calculator

text: At the start of the 1970s, hand-held electronic calculators were very costly, at two or three weeks' wages, and so were a luxury item. The high price was due to their construction requiring many mechanical and electronic components which were costly to produce, and production runs that were too small to exploit economies of scale. Many firms saw that there were good profits to be made in the calculator business with the margin on such high prices. However, the cost of calculators fell as components and their production methods improved, and the effect of economies of scale was felt.


title: Calculator

text: By 1976, the cost of the cheapest four-function pocket calculator had dropped to a few dollars, about 1/20 of the cost five years before. The results of this were that the pocket calculator was affordable, and that it was now difficult for the manufacturers to make a profit from calculators, leading to many firms dropping out of the business or closing. The firms that survived making calculators tended to be those with high outputs of higher quality calculators, or producing high-specification scientific and programmable calculators.


title: Calculator

text: The first calculator capable of symbolic computing was the HP-28C, released in 1987. It could, for example, solve quadratic equations symbolically. The first graphing calculator was the Casio fx-7000G released in 1985.


title: Calculator

text: The two leading manufacturers, HP and TI, released increasingly feature-laden calculators during the 1980s and 1990s. At the turn of the millennium, the line between a graphing calculator and a handheld computer was not always clear, as some very advanced calculators such as the TI-89, the Voyage 200 and HP-49G could differentiate and integrate functions, solve differential equations, run word processing and PIM software, and connect by wire or IR to other calculators/computers.


title: Calculator

text: The HP 12c financial calculator is still produced. It was introduced in 1981 and is still being made with few changes. The HP 12c featured the reverse Polish notation mode of data entry. In 2003 several new models were released, including an improved version of the HP 12c, the "HP 12c platinum edition" which added more memory, more built-in functions, and the addition of the algebraic mode of data entry.


title: Calculator

text: Calculated Industries competed with the HP 12c in the mortgage and real estate markets by differentiating the key labeling; changing the "I", "PV", "FV" to easier labeling terms such as "Int", "Term", "Pmt", and not using the reverse Polish notation. However, CI's more successful calculators involved a line of construction calculators, which evolved and expanded in the 1990s to present. According to Mark Bollman, a mathematics and calculator historian and associate professor of mathematics at Albion College, the "Construction Master is the first in a long and profitable line of CI construction calculators" which carried them through the 1980s, 1990s, and to the present.


title: Calculator

text: Personal computers often come with a calculator utility program that emulates the appearance and functions of a calculator, using the graphical user interface to portray a calculator. One such example is Windows Calculator. Most personal data assistants (PDAs) and smartphones also have such a feature.


title: Calculator

text: In most countries, students use calculators for schoolwork. There was some initial resistance to the idea out of fear that basic or elementary arithmetic skills would suffer. There remains disagreement about the importance of the ability to perform calculations "in the head", with some curricula restricting calculator use until a certain level of proficiency has been obtained, while others concentrate more on teaching estimation methods and problem-solving. Research suggests that inadequate guidance in the use of calculating tools can restrict the kind of mathematical thinking that students engage in. Others have argued that calculator use can even cause core mathematical skills to atrophy, or that such use can prevent understanding of advanced algebraic concepts. In December 2011 the UK's Minister of State for Schools, Nick Gibb, voiced concern that children can become "too dependent" on the use of calculators. As a result, the use of calculators is to be included as part of a review of the Curriculum. In the United States, many math educators and boards of education have enthusiastically endorsed the National Council of Teachers of Mathematics (NCTM) standards and actively promoted the use of classroom calculators from kindergarten through high school.


title: Sachin Tendulkar

text: Sachin Ramesh Tendulkar (; ; born 24 April 1973) is an Indian former international cricketer who captained the Indian national team. He is regarded as one of the greatest batsmen in the history of cricket. He is the all time highest run-scorer in both ODI and Test Format with more than 18000 runs and 15000 runs respectively in total. He also holds the record for receiving most Man-of-the-match awards in International Cricket with all forms combined. He is sometimes referred to as "The God of Cricket" in India. A film with that name was released in 2021.


title: Sachin Tendulkar

text: Tendulkar took up cricket at the age of eleven, made his Test match debut on 15 November 1989 against Pakistan in Karachi at the age of sixteen, and went on to represent Mumbai domestically and India internationally for close to twenty-four years. In 2002, halfway through his career, "Wisden" ranked him the second-greatest Test batsman of all time, behind Don Bradman, and the second-greatest ODI batsman of all time, behind Viv Richards. Later in his career, Tendulkar was part of the Indian team that won the 2011 Cricket World Cup, his first win in six World Cup appearances for India. He had previously been named "Player of the Tournament" at the 2003 edition of the tournament.


title: Sachin Tendulkar

text: Tendulkar received the Arjuna Award in 1994 for his outstanding sporting achievements, the Khel Ratna Award, India's highest sporting honour, in 1997, and the Padma Shri and Padma Vibhushan awards in 1999 and 2008, respectively, two of India's highest civilian awards. A few hours after the end of his last match in November 2013, the Prime Minister's Office announced the decision to award him the Bharat Ratna, India's highest civilian award. As of 2021, he is the youngest recipient to date and was the first sportsperson to receive the award. In 2012, Tendulkar was nominated to the Rajya Sabha, the upper house of the Parliament of India.


title: Sachin Tendulkar

text: In 2010, "Time" magazine included Tendulkar in its annual Time 100 list as one of the most influential people in the world.Tendulkar was awarded the Sir Garfield Sobers Trophy for cricketer of the year at the 2010 ICC Awards.


title: Sachin Tendulkar

text: Having retired from ODI cricket in 2012, he retired from all forms of cricket in November 2013 after playing his 200th Test match. Tendulkar played 664 international cricket matches in total, scoring 34,357 runs. In 2013, Tendulkar was included in an compiled in 2013 to mark the 150th anniversary of "Wisden Cricketers' Almanack", and he was the only specialist batsman of the post–World War II era, along with Viv Richards, to get featured in the team. In 2019 he was inducted into the ICC Cricket Hall of Fame.


title: Sachin Tendulkar

text: Tendulkar spent his formative years in the "Sahitya Sahawas Cooperative Housing Society" in Bandra (East). As a young boy, Tendulkar was considered a bully, and often picked up fights with new children in his school.


title: Sachin Tendulkar

text: Tendulkar also showed an interest in tennis that was on an equal level to cricket. He particularly idolised American player John McEnroe, and emulated his hero by growing his hair long at the age of 7 or 8 years. At this time, Tendulkar also regularly wore tennis wristbands and headbands, and carried a tennis racquet with him as a sign of his love for tennis.


title: Sachin Tendulkar

text: To help curb his mischievous, bullying tendencies, Ajit Tendulkar, his elder brother introduced Sachin to cricket in 1984. He introduced him to Ramakant Achrekar, a famous cricket coach and a club cricketer of repute, at Shivaji Park, Dadar. In the first meeting, the Sachin did not able to play his best game. Ajit told Achrekar that he was feeling self-conscious due to the coach observing him, and was not displaying his natural game. Ajit requested the coach to give him another chance at playing, but watch while hiding behind a tree. This time, Sachin, apparently unobserved, played much better and was accepted at Achrekar's academy. Ajit Tendulkar also had experience of playing cricket in Bombay's Kanga Cricket League.


title: Sachin Tendulkar

text: Achrekar was impressed with Tendulkar's talent and advised him to shift his schooling to "Sharadashram Vidyamandir" (English) High School, a school at Dadar which had a dominant cricket team and had produced many notable cricketers. Prior to this, Tendulkar had attended the Indian Education Society's New English School in Bandra (East). He was also coached under the guidance of Achrekar at Shivaji Park in the mornings and evenings. Tendulkar would practice for hours on end in the nets. If he became exhausted, Achrekar would put a one-rupee coin on the top of the stumps, and the bowler who dismissed Tendulkar would get the coin. If Tendulkar passed the whole session without getting dismissed, the coach would give him the coin. Tendulkar now considers the 13 coins he won then as some of his most prized possessions. He moved in with his aunt and uncle, who lived near Shivaji Park, during this period, due to his hectic schedule.


title: Sachin Tendulkar

text: Meanwhile, at school, he developed a reputation as a child prodigy. He had become a common conversation point in local cricketing circles, where there were suggestions already that he would become one of the greats. Sachin consistently featured in the school team in the "Matunga Gujarati Seva Mandal" (MGSM) Shield. Besides school cricket, he also played club cricket, initially representing John Bright Cricket Club in Bombay's premier club cricket tournament, the Kanga Cricket League, and later went on to play for the Cricket Club of India (CCI). In 1987, at the age of 14, he attended the MRF Pace Foundation in Madras (now Chennai) to train as a fast bowler, but the Australian fast bowler Dennis Lillee, who took a world record 355 Test wickets, was unimpressed, suggesting that Tendulkar focus on his batting instead. On 20 January 1987, he also turned out as substitute for Imran Khan's side in an exhibition game at Brabourne Stadium in Bombay, to mark the golden jubilee of Cricket Club of India. A couple of months later, former Indian batsman Sunil Gavaskar gave him a pair of his own ultra light pads and consoled him to not get disheartened for not getting the Bombay Cricket Association's "Best Junior Cricketer Award" (He was 14 years that time). "It was the greatest source of encouragement for me," Tendulkar said nearly 20 years later after surpassing Gavaskar's world record of 34 Test centuries. Sachin served as a ball boy in the 1987 Cricket World Cup when India played against England in the semifinal in Bombay. In his season in 1988, Tendulkar scored a century in every innings he played. He was involved in an unbroken 664-run partnership in a Lord Harris Shield inter-school game against St. Xavier's High School in 1988 with his friend and teammate Vinod Kambli, who would also go on to represent India. Tendulkar scored 326 (not out) in this innings and scored over a thousand runs in the tournament. This was a record partnership in any form of cricket until 2006, when it was broken by two under-13 batsmen in a match held at Hyderabad in India.


title: Sachin Tendulkar

text: On 14 November 1987, the 14-year-old Tendulkar was selected to represent Bombay in the Ranji Trophy, India's premier domestic First-class cricket tournament, for the 1987–88 season. However, he was not selected for the final eleven in any of the matches, though he was often used as a substitute fielder. He narrowly missed out on playing alongside his idol Gavaskar, who had retired from all forms of cricket after the 1987 Cricket World Cup. A year later, on 11 December 1988, aged 15 years and 232 days, Tendulkar made his debut for Bombay against Gujarat at Wankhede stadium and scored 100 not out in that match, making him the youngest Indian to score a century on debut in first-class cricket. He was selected to play for the team by the then Bombay captain Dilip Vengsarkar after watching him easily playing India's best fast bowler at the time, Kapil Dev, in the Wankhede Stadium's Cricket practice nets, where the Indian team had come to play against the touring New Zealand team. He followed this by scoring a century in his first Deodhar and Duleep Trophies, which are also Indian domestic tournaments.


title: Sachin Tendulkar

text: Tendulkar finished the 1988–89 Ranji Trophy season as Bombay's highest run-scorer. He scored 583 runs at an average of 67.77, and was the eighth-highest run-scorer overall. In 1995–96 Irani trophy he captained Mumbai against Rest of India team. He also made an unbeaten century in the Irani Trophy match against Delhi at the start of the 1989–90 season, playing for the Rest of India. Sachin was picked for a young Indian team to tour England twice, under the Star Cricket Club banner in 1988 and 1989. In the famous 1990–91 Ranji Trophy final, in which Haryana defeated Bombay by two runs after leading in the first innings, Tendulkar's 96 from 75 balls was a key to giving Bombay a chance of victory as it attempted to chase 355 from only 70 overs on the final day.


title: Sachin Tendulkar

text: In the final of 1995 Ranji trophy, Tendulkar scored 140 and 139 versus Punjab at Wankhede playing as a captain. Against Haydrabad 53, 128 in 2000, 105, 43 against Bengal in 2007 are the innings he played for Mumbai in the final of Ranji trophy at Wankhede stadium.


title: Sachin Tendulkar

text: His first double century (204*) was for Mumbai while playing against the visiting Australian team at the Brabourne Stadium in 1998. He is the only player to score a century on debut in all three of his domestic first-class tournaments (the Ranji, Irani, and Duleep Trophies). Another double century was an innings of 233* against Tamil Nadu in the semi-finals of the 2000 Ranji Trophy, which he regards as one of the best innings of his career.


title: Sachin Tendulkar

text: In 1992, at the age of 19, Tendulkar became the first overseas-born player to represent Yorkshire, which prior to Tendulkar joining the team, never selected players even from outside Yorkshire. Selected for Yorkshire as a replacement for the injured Australian fast bowler Craig McDermott, Tendulkar played 16 first-class matches for the county and scored 1070 runs at an average of 46.52.


title: Sachin Tendulkar

text: Raj Singh Dungarpur is credited for the selection of Tendulkar for the Indian tour of Pakistan in late 1989, after one first class season. The Indian selection committee had shown interest in selecting Tendulkar for the tour of the West Indies held earlier that year, but eventually did not select him, as they did not want him to be exposed to the dominant fast bowlers of the West Indies so early in his career. Tendulkar made his Test debut against Pakistan in Karachi in November 1989 aged 16 years and 205 days. He made 15 runs, being bowled by Waqar Younis, who also made his debut in that match, but was noted for how he handled numerous blows to his body at the hands of the Pakistani pace attack. In the fourth and final Test in Sialkot, he was hit on the nose by a bouncer bowled by Younis, but he declined medical assistance and continued to bat even as he gushed blood from it. In a 20-over exhibition game in Peshawar, held in parallel with the bilateral series, Tendulkar made 53 runs off 18 balls, including an over in which he scored 27 runs (6, 4, 0, 6, 6, 6) off leg-spinner Abdul Qadir. This was later called "one of the best innings I have seen" by the then Indian captain Krishnamachari Srikkanth. In all, he scored 215 runs at an average of 35.83 in the Test series, and was dismissed without scoring a run in the only One Day International (ODI) he played. Thus Sachin Tendulkar became the youngest player to debut for India in Tests at the age of 16 years and 205 days and also the youngest player to debut for India in ODIs at the age of 16 years and 238 days.


title: Sachin Tendulkar

text: The series was followed by a tour of New Zealand in which he scored 117 runs at an average of 29.25 in Tests including an innings of 88 in the second Test. He was dismissed without scoring in one of the two one-day games he played, and scored 36 in the other. On his next tour, a summer tour to England of 1990, on 14 August, he became the second youngest cricketer to score a Test century as he made 119 not out in the second Test at Old Trafford in Manchester, an innings which contributed to a draw and saved India from certain defeat in the match. Wisden described his innings as "a disciplined display of immense maturity" and also wrote:


title: Sachin Tendulkar

text: He looked the embodiment of India's famous opener, Gavaskar, and indeed was wearing a pair of his pads. While he displayed a full repertoire of strokes in compiling his maiden Test hundred, most remarkable were his off-side shots from the back foot. Though only 5ft 5in tall, he was still able to control without difficulty short deliveries from the English pacemen.


title: Sachin Tendulkar

text: Tendulkar further enhanced his reputation as a future great during the 1991–92 tour of Australia held before the 1992 Cricket World Cup, that included an unbeaten 148 in the third Test at Sydney, making him the youngest batsman to score a century in Australia. He then scored 114 on a fast, bouncing pitch in the final Test at Perth against a pace attack comprising Merv Hughes, Bruce Reid and Craig McDermott. Hughes commented to Allan Border at the time that "This little prick's going to get more runs than you, AB."


title: Sachin Tendulkar

text: Tendulkar's performance through the years 1994–1999 coincided with his physical peak, in his early twenties. He opened the batting at Auckland against New Zealand in 1994, making 82 runs off 49 balls. He scored his first ODI century on 9 September 1994 against Australia in Sri Lanka at Colombo. It took him 78 ODIs to score his first century.


title: Sachin Tendulkar

text: Tendulkar's rise continued when he was the leading run scorer at the 1996 World Cup, scoring two centuries. He was the only Indian batsman to perform well in the semi-final against Sri Lanka. Tendulkar fell amid a batting collapse and the match referee, Clive Lloyd, awarded Sri Lanka the match after the crowd began rioting and throwing litter onto the field.


title: Sachin Tendulkar

text: After the World Cup, in the same year against Pakistan at Sharjah, Indian captain Mohammed Azharuddin was going through a lean patch. Tendulkar and Navjot Singh Sidhu both made centuries to set a then record partnership for the second wicket. After getting out, Tendulkar found Azharuddin in two minds about whether he should bat. Tendulkar convinced Azharuddin to bat and Azharuddin subsequently unleashed 24 runs off one over. India went on to win that match. It enabled India to post a score in excess of 300 runs for the first time in an ODI.


title: Sachin Tendulkar

text: Sachin scored 143 (131) runs in Sharjah against the mighty Australian team in the 1998 Coca-Cola cup, including 5 sixes in an inning against Shane Warne, Damien Fleming and Michael Kasprowicz. Per ICC's poll, it is the best one-day inning from Tendulkar. This inning of Tendulkar's is know as "Desert storm" due to this match being interrupted by a desert storm.


title: Sachin Tendulkar

text: This was the beginning of a period at the top of the batting world, culminating in the Australian tour of India in early 1998, with Tendulkar scoring three consecutive centuries. The focus was on the clash between Tendulkar, the world's most dominating batsman and Shane Warne, the world's leading spinner, both at the peak of their careers, clashing in a Test series. In the lead-up to the series, Tendulkar simulated scenarios in the nets with Laxman Sivaramakrishnan, the former India leg spinner, donning the role of Warne. In their tour opener, Australia faced the then Ranji Champions Mumbai at the Brabourne Stadium in a three-day first class match. Tendulkar made an unbeaten 204 as Shane Warne conceded 111 runs in 16 overs and Australia lost the match within three days. He also had a role with the ball in the five-match ODI series in India following the Tests, including a five wicket haul in an ODI in Kochi. Set 310 runs to win, Australia were cruising at 203 for 3 in the 31st over when Tendulkar turned the match for India, taking the wickets of Michael Bevan, Steve Waugh, Darren Lehmann, Tom Moody and Damien Martyn for 32 runs in 10 overs. The Test match success was followed by two consecutive centuries in April 1998 in a Triangular cricket tournament in Sharjah—the first in a must-win game to take India to the finals and then again in the finals, both against Australia. These twin knocks were also known as the Desert Storm innings. Following the series, Warne ruefully joked that he was having nightmares about his Indian nemesis.


title: Sachin Tendulkar

text: Tendulkar's contribution in the ICC 1998 quarterfinal at Dhaka paved the way for India's entry into the semifinals, when he took four Australian wickets after scoring 141 runs in 128 balls.


title: Sachin Tendulkar

text: The inaugural Asian Test Championship took place in February and March 1999, involving India, Pakistan, and Sri Lanka. In the first match, between India and Pakistan in Eden Gardens, Tendulkar was run out for nine after colliding with Pakistan bowler Shoaib Akhtar. Around 100,000 people came to support India during the initial four days of the tournament, breaking a 63-year-old record for aggregate Test attendance record. The crowd's reaction to Tendulkar's dismissal was to throw objects at Akhtar, and the players were taken off the field. The match resumed after Tendulkar and the president of the ICC appealed to the crowd; however, further rioting meant that the match was finished in front of a crowd of 200 people. Tendulkar scored his 19th Test century in the second Test and the match resulted in a draw with Sri Lanka. India did not progress to the final, which was won by Pakistan, and refused to participate the next time the championship was held due to increasing political tensions between India and Pakistan.


title: Sachin Tendulkar

text: In the Test against Pakistan at Chepauk in 1999, the first of a two-Test series, Sachin scored 136 in the fourth innings with India chasing 271 for victory. However, he was out when India needed 17 more runs to win, triggering a batting collapse, and India lost the match by 12 runs. The worst was yet to come as Professor Ramesh Tendulkar, Sachin's father, died in the middle of the 1999 Cricket World Cup. Tendulkar flew back to India to attend the final rituals of his father, missing the match against Zimbabwe. However, he returned to the World Cup scoring a century (140 not out of 101 balls) in his very next match against Kenya in Bristol. He dedicated this century to his father.


title: Sachin Tendulkar

text: Tendulkar's two tenures as captain of the Indian cricket team were not very successful. When Tendulkar took over as captain in 1996, it was with huge hopes and expectations. However, by 1997 the team was performing poorly. Azharuddin was credited with saying ""Nahin jeetega! Chote ki naseeb main jeet nahin hai!"", which translates into: "He won't win! It's not in the small one's destiny!".


title: Sachin Tendulkar

text: Tendulkar, succeeding Azharuddin as captain for his second term, led India on a tour of Australia, where the visitors were beaten 3–0 by the newly crowned world champions. Tendulkar, however, won the player of the series award as well as player of the match in one of the games. After another Test series defeat, this time by a 0–2 margin at home against South Africa, Tendulkar resigned, and Sourav Ganguly took over as captain in 2000.


title: Sachin Tendulkar

text: During the Indian team's 2007 tour of England, the desire of Rahul Dravid to resign from the captaincy became known. Then Board of Control for Cricket in India (BCCI) President Sharad Pawar offered the captaincy to Tendulkar, who instead recommended Mahendra Singh Dhoni to take over the reins. Pawar later revealed this conversation, crediting Tendulkar for first forwarding the name of Dhoni, who since achieved much success as captain.


title: Sachin Tendulkar

text: In the year of 2000 a huge match fixing scandal happened in Indian cricket. After the incident Sachin Tendulkar and other 3 senior cricketers played important role ensured that the players banned by BCCI and whose performance was dubious were never picked for the Indian team again. Sachin and co. did this work quietly without doing public statements.


title: Sachin Tendulkar

text: The continued calls for Tendulkar to be made captain, the offer of captaincy in 2007 and his rejection of the offer, there are numerous articles relating to where his faults were in captaincy.


title: Sachin Tendulkar

text: In India's 2001 tour of South Africa in the second test match between India and South Africa at St George's Park, Port Elizabeth, match referee Mike Denness fined four Indian players for excessive appealing, as well as fined the Indian captain Sourav Ganguly for not controlling his team. Tendulkar was given a suspended ban of one game by Denness in light of alleged ball tampering. Television cameras picked up images that suggested Tendulkar may have been involved in cleaning the seam of the cricket ball. This can, under some conditions, amount to altering the condition of the ball. Denness found Sachin Tendulkar guilty of ball tampering charges and handed him a one Test match ban. The incident escalated to include sports journalists accusing Denness of racism, and led to Denness being barred from entering the venue of the third Test match. The ICC revoked the status of the match as a Test as the teams rejected the appointed referee. The charges against Tendulkar and Sehwag's ban for excessive appealing triggered a massive backlash from the Indian public.


title: Sachin Tendulkar

text: Sachin Tendulkar continued performing well in Test cricket in 2001 and 2002, with some pivotal performances with both bat and ball. Tendulkar took three wickets on the final day of the famous Kolkata Test against Australia in 2001, including the key wickets of Matthew Hayden and Adam Gilchrist, who were centurions in the previous Test. His three wickets haul helped India win the match. In the five-match ODI series that followed, he took his 100th wicket in ODIs, claiming the wicket of then Australian captain Steve Waugh in the final match at the Fatorda Stadium in Goa.


title: Sachin Tendulkar

text: In the 2002 series in the West Indies, Tendulkar started well, scoring 79 in the first Test. In the second Test at Port of Spain, Sachin Tendulkar scored 117 in the first innings, his 29th Test century in his 93rd Test match, to equal Sir Donald Bradman's record of 29 Test hundreds. He was gifted a Ferrari 360 Modena by Fiat through Michael Schumacher for achieving this feat.


title: Sachin Tendulkar

text: Then, in a hitherto unprecedented sequence, he scored 0, 0, 8 and 0 in the next four innings. He returned to form in the last Test scoring 41 and 86, one half century. However, India lost the series. In this period, in the third Test match against England in August 2002, Sachin scored his 30th Test century to surpass Bradman's haul, in his 99th Test match.


title: Sachin Tendulkar

text: Tendulkar made 673 runs in 11 matches in the 2003 Cricket World Cup, helping India reach the final. While Australia retained the trophy that they had won in 1999, Tendulkar was given the Man of the Tournament award.


title: Sachin Tendulkar

text: He continued to score heavily in ODI cricket that year, with two hundreds in a tri-series involving New Zealand and Australia. As a part-time bowler, he dismissed an exhausted centurion, Matthew Hayden in the tri-series final.