1.
Golden toad
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The golden toad was a small true toad that was once abundant in a small, high-altitude region about 4 square kilometres in an area north of the city of Monteverde, Costa Rica. It was endemic to cloud forest. Also called the Monte Verde toad, Alajuela toad and orange toad and this toad was first described in 1966 by herpetologist Jay Savage. The last sighting of a male golden toad was on 15 May 1989. The golden toad was one of more than 500 species in the family Bufonidae—the true toads. Males were orange and sometimes slightly mottled on the belly, while females showed a variety of colors, including black, yellow, red, green. Females were typically larger than males, body length ranged from 39 to 48 mm in males and from 42 to 56 mm in females. Males had proportionally longer limbs and longer, more acute noses than females, females also had enlarged cranial crests above the level of the orbit, while in males the crests were much lower. Individuals spent the majority of their lives in moist underground burrows, the average lifespan of the golden toad is unknown, but other amphibian species in the family Bufonidae have an average lifespan of 10–12 years. The golden toad inhabited northern Costa Rica’s Monteverde Cloud Forest Reserve and it was distributed over an area no more than 8 km2 and possibly as little as 0.5 km2 in extent, at an average elevation of 1,500 to 1,620 m. The species seemed to prefer the lower elevations, the golden toads main habitat was on a cold, wet ridge called Brillante. They would emerge in late March through April to mate for the first few weeks in rainwater pools amongst tree roots,1500 golden toads were reported to breed at the site since 1972. The last documented breeding episode occurred from April–May 1987, for a few weeks in April, after the dry season ended and the forest became wetter, males would gather in large numbers near ground puddles and wait for the females. Golden toads were found to breed explosively when it rained heavily from March to June, males would clasp onto any other individuals encountered and only then identify the partners gender. As soon as a found a female golden toad, he would engage in amplexus with the female until she laid spawned. The males would fight each other for opportunities to mate until the end of their short mating season. Males outnumbered females, in years by as many as ten to one. During the 1977 and 1982 seasons, males outnumbered females by over 8 to 1 at breeding pools, each toad couple produced 200–400 eggs each week for the six week mating period, with each egg approximately 3 mm in diameter
2.
Monteverde
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Monteverde, Costa Rica is a small community in Puntarenas, Costa Rica, located in the Cordillera de Tilarán. Roughly a four-hour drive from the Central Valley, Monteverde is considered a major destination in Costa Rica. The area is host to the Monteverde Cloud Forest Reserve and numerous other reserves, National Geographic has called the Monteverde Cloud Forest Biological Reserve the jewel in the crown of cloud forest reserves. Newsweek has declared Monteverde the worlds #14 Place to Remember Before it Disappears and this article deals with Monteverde and its surrounding zone. Resting roughly at 1,400 metres above sea level, Monteverde is misty, humid, annual rainfall averages around 3,000 millimetres. Humidity oscillates between 74% and 97%, various pre-Columbian artifacts testify to the longtime occupancy of the Monteverde region by a small population of Clovis Native Americans, who once farmed in villages circa 3000 BC. Between roughly 3300 BC to 2000 BC, the tribes of the Arenal area experienced a population decline. These nearby tribes re-established villages in the region between 2000 BC to 500 BC, agriculture intensified in the 500 BC to AD300 period, with chiefdom societies replacing small tribal societies. Intense deforestation accompanied horticulture, and stone foundations dating to this period can be found, jade objects became prominent characteristics of these villages. From AD300 to 800, complex chiefdoms supplanted simpler chiefdoms and more intricate villages appear, with cemeteries, public squares, gold-work and inter-tribal trade, around 1300, a general decline in population occurred, possibly due to Arenal Volcanos increased activity. When the Spanish arrived in 1502, Costa Rica endured two generations of warfare, nationwide indigenous populations fell from an estimated 400,000 to 80,000 within little more than 50 years. In the first three decades of the 20th century, Creole populations arrived in numbers to what is now called Monteverde. Many were employed by, or provided services to the employees of, many settled the nearby lower, warmer valley of San Luis. What is now considered Monteverde was founded by Quakers from the United States whose pacifist values led them to defy the American draft before the Korean War. The majority of the group hailed from Fairhope, Alabama, and it included people who were not Quakers but pacifists, the spokesman of the group was Hubert Mendenhall, a dairyman who had visited Costa Rica in 1949 after joining a farmers tour. These Quakers and pacifists chose Monteverde for its climate, which would facilitate dairy farming. Mendenhall noted that the soil was fertile and the people were friendly as well, the Quakers stewarded and farmed a large tract of land, which they eventually set aside for conservation. This reserve, which was named the Reserva Biológica Bosque Nuboso Monteverde, has become a major tourist attraction, on March 8,2005, a group of three armed Nicaraguan men raided and attempted to rob the Monteverde branch of the state National Bank
3.
Costa Rica
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It has a population of around 4.5 million, of whom nearly a quarter live in the metropolitan area of the capital and largest city, San José. Costa Rica was sparsely inhabited by people before coming under Spanish rule in the 16th century. Since then, Costa Rica has remained among the most stable, prosperous, following a brief civil war, it permanently abolished its army in 1949, becoming one of only a few sovereign nations without a standing army. Costa Rica is a member of the Organisation Internationale de la Francophonie. The country has consistently performed favourably in the Human Development Index, placing 69th in the world as of 2015 and its rapidly developing economy, once heavily dependent on agriculture, has diversified to include sectors such as finance, pharmaceuticals, and ecotourism. Costa Rica is known for its environmental policies, being the only country to meet all five UNDP criteria established to measure environmental sustainability. Costa Rica officially plans to become a country by 2021. In 2012, it became the first country in the Americas to ban recreational hunting, historians have classified the indigenous people of Costa Rica as belonging to the Intermediate Area, where the peripheries of the Mesoamerican and Andean native cultures overlapped. More recently, pre-Columbian Costa Rica has also described as part of the Isthmo-Colombian Area. The oldest evidence of occupation in Costa Rica is associated with the arrival of various groups of hunter-gatherers about 10,000 to 7,000 years BCE in the Turrialba Valley. The presence of Clovis culture type spearheads and arrows from South America opens the possibility that, in this area, agriculture became evident in the populations that lived in Costa Rica about 5,000 years ago. They mainly grew tubers and roots, for the first and second millennia BCE there were already settled farming communities. These were small and scattered, although the transition from hunting and gathering to agriculture as the livelihood in the territory is still unknown. The earliest use of pottery appears around 2,000 to 3,000 BCE, shards of pots, cylindrical vases, platters, gourds and other forms of vases decorated with grooves, prints, and some modelled after animals have been found. The impact of indigenous peoples on modern Costa Rican culture has been small compared to other nations. Costa Rica was described as the poorest and most miserable Spanish colony in all America by a Spanish governor in 1719, for all these reasons, Costa Rica was, by and large, unappreciated and overlooked by the Spanish Crown and left to develop on its own. Costa Rica became a democracy with no oppressed mestizo or indigenous class. It was not long before Spanish settlers turned to the hills, where they found rich volcanic soil, like the rest of Central America, Costa Rica never fought for independence from Spain
4.
Extinction event
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An extinction event is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a change in the diversity. It occurs when the rate of extinction increases with respect to the rate of speciation, Extinction occurs at an uneven rate. Based on the record, the background rate of extinctions on Earth is about two to five taxonomic families of marine animals every million years. Marine fossils are used to measure extinction rates because of their superior fossil record. The Great Oxygenation Event was probably the first major extinction event, since the Cambrian explosion five further major mass extinctions have significantly exceeded the background extinction rate. In addition to the five mass extinctions, there are numerous minor ones as well. Mass extinctions seem to be a mainly Phanerozoic phenomenon, with extinction rates low before large complex organisms arose, estimates of the number of major mass extinctions in the last 540 million years range from as few as five to more than twenty. These differences stem from the chosen for describing an extinction event as major. In a landmark paper published in 1982, Jack Sepkoski and David M. Raup identified five mass extinctions, the Big Five cannot be so clearly defined, but rather appear to represent the largest of a relatively smooth continuum of extinction events. Cretaceous–Paleogene extinction event,66 Ma at the Cretaceous -Paleogene transition interval, the event formerly called the Cretaceous-Tertiary or K–T extinction or K-T boundary is now officially named the Cretaceous–Paleogene extinction event. About 17% of all families, 50% of all genera and 75% of all species became extinct, in the seas all the ammonites, plesiosaurs and mosasaurs disappeared and the percentage of sessile animals was reduced to about 33%. All non-avian dinosaurs became extinct during that time, the boundary event was severe with a significant amount of variability in the rate of extinction between and among different clades. Mammals and birds, the latter descended from dinosaurs, emerged as dominant large land animals. Triassic–Jurassic extinction event,201.3 Ma at the Triassic-Jurassic transition, about 23% of all families, 48% of all genera and 70% to 75% of all species became extinct. Most non-dinosaurian archosaurs, most therapsids, and most of the amphibians were eliminated. Non-dinosaurian archosaurs continued to dominate aquatic environments, while non-archosaurian diapsids continued to dominate marine environments, the Temnospondyl lineage of large amphibians also survived until the Cretaceous in Australia. Permian–Triassic extinction event,252 Ma at the Permian-Triassic transition, Earths largest extinction killed 57% of all families, 83% of all genera and 90% to 96% of all species
5.
Amphibian
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Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. They inhabit a variety of habitats, with most species living within terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, the young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a respiratory surface and some small terrestrial salamanders and frogs lack lungs. They are superficially similar to lizards but, along with mammals and birds, reptiles are amniotes, the earliest amphibians evolved in the Devonian period from sarcopterygian fish with lungs and bony-limbed fins, features that were helpful in adapting to dry land. They diversified and became dominant during the Carboniferous and Permian periods, over time, amphibians shrank in size and decreased in diversity, leaving only the modern subclass Lissamphibia. The three modern orders of amphibians are Anura, Urodela, and Apoda, the number of known amphibian species is approximately 7,000, of which nearly 90% are frogs. The smallest amphibian in the world is a frog from New Guinea with a length of just 7.7 mm. The largest living amphibian is the 1.8 m Chinese giant salamander, the study of amphibians is called batrachology, while the study of both reptiles and amphibians is called herpetology. The word amphibian is derived from the Ancient Greek term ἀμφίβιος, the term was initially used as a general adjective for animals that could live on land or in water, including seals and otters. Traditionally, the class Amphibia includes all tetrapod vertebrates that are not amniotes, the numbers of species cited above follows Frost and the total number of known amphibian species is over 7,000, of which nearly 90% are frogs. With the phylogenetic classification, the taxon Labyrinthodontia has been discarded as it is a group without unique defining features apart from shared primitive characteristics. Classification varies according to the phylogeny of the author and whether they use a stem-based or a node-based classification. The phylogeny of Paleozoic amphibians is uncertain, and Lissamphibia may possibly fall within groups, like the Temnospondyli or the Lepospondyli. If the common ancestor of amphibians and amniotes is included in Amphibia, all modern amphibians are included in the subclass Lissamphibia, which is usually considered a clade, a group of species that have evolved from a common ancestor. The three modern orders are Anura, Caudata, and Gymnophiona, although the fossils of several older proto-frogs with primitive characteristics are known, the oldest true frog is Prosalirus bitis, from the Early Jurassic Kayenta Formation of Arizona. It is anatomically similar to modern frogs. The oldest known caecilian is another Early Jurassic species, Eocaecilia micropodia, the earliest salamander is Beiyanerpeton jianpingensis from the Late Jurassic of northeastern China
6.
Population decline
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Population decline can refer to the decline in population of any organism, but this article refers to population decline in humans. It is a term used to describe any great reduction in a human population. Sometimes known as depopulation, population decline is the reduction over time in a regions population, the decline can be caused by several factors including sub-replacement fertility, heavy emigration, disease, famine, and war. History is replete with examples of large-scale depopulations, many wars, for example, have been accompanied by significant depopulations. Before the 20th century, population decline was observed due to disease. In modern times, the AIDS epidemic caused declines in the population of some African countries, less frequently, population declines are caused by genocide or mass execution, for example, in the 1970s, the population of Cambodia declined because of wide-scale executions by the Khmer Rouge. Sometimes the term underpopulation is applied to an economic system. Underpopulation is usually defined as a state in which a population has declined too much to support its current economic system. An example would be if retirees were supported through a security system which does not invest savings. In this case, the younger generation may not be able to support the older generation, since the dire predictions of coming population overshoot in the 1960s and 70s, more couples have tended to choose to have fewer children. Today, emigration, sub-replacement fertility and high rates in the former Soviet Union. However, governments can influence the speed of the decline, including measures to halt, such measures include pro-birth policies and subsidies, media influence, immigration, bolstering healthcare and laws aimed at reducing death rates. Such is the case in Russia, Armenia, and many Western European nations who have used immigration, therefore, although the long-term trend may be for greater population decline, short term trends may slow the decline or even reverse it, creating seemingly conflicting statistical data. A great example of changing trends occurring over a century is Ireland, statistical data, especially comparing only two sets of figures, can show an incorrect population trend. A nations population could be increasing, but an event could have resulted in decline. Political instability can render an area within a nations count unreliable for comparison, a common misreading is due to time. Therefore, numerous sets of statistics should be interpreted to get an idea of a trend, a number of nations today face population decline. Countries rapidly approaching long-term population declines include Spain, Cuba, Uruguay, Denmark, Finland, Russia also faces long-term population decline, although the trend has been stalled through a reversal of stagnant birth rates
7.
Extinction
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In biology and ecology, extinction is the end of an organism or of a group of organisms, normally a species. The moment of extinction is considered to be the death of the last individual of the species, although the capacity to breed. Because a species range may be very large, determining this moment is difficult. This difficulty leads to such as Lazarus taxa, where a species presumed extinct abruptly reappears after a period of apparent absence. More than 99 percent of all species, amounting to five billion species. Estimates on the number of Earths current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described, the relationship between animals and their ecological niches has been firmly established. Mass extinctions are relatively rare events, however, isolated extinctions are quite common, only recently have extinctions been recorded and scientists have become alarmed at the current high rate of extinctions. Most species that become extinct are never scientifically documented, some scientists estimate that up to half of presently existing plant and animal species may become extinct by 2100. A dagger symbol next to a name is often used to indicate its extinction. A species is extinct when the last existing member dies, Extinction therefore becomes a certainty when there are no surviving individuals that can reproduce and create a new generation. Pinpointing the extinction of a species requires a definition of that species. If it is to be declared extinct, the species in question must be distinguishable from any ancestor or daughter species. Extinction of a plays a key role in the punctuated equilibrium hypothesis of Stephen Jay Gould. In ecology, extinction is often used informally to refer to local extinction, in which a species ceases to exist in the area of study. This phenomenon is known as extirpation. Local extinctions may be followed by a replacement of the species taken from other locations, species which are not extinct are termed extant. Those that are extant but threatened by extinction are referred to as threatened or endangered species, currently an important aspect of extinction is human attempts to preserve critically endangered species
8.
Biodiversity
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Biodiversity, a contraction of biological diversity, generally refers to the variety and variability of life on Earth. One of the most widely used definitions defines it in terms of the variability within species and it is a measure of the variety of organisms present in different ecosystems. This can refer to genetic variation, ecosystem variation, or species variation within an area, biome, terrestrial biodiversity tends to be greater near the equator, which seems to be the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth, and is richest in the tropics and these tropical forest ecosystems cover less than 10 per cent of earths surface, and contain about 90 percent of the worlds species. Marine biodiversity tends to be highest along coasts in the Western Pacific, there are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time, the number and variety of plants, animals and other organisms that exist is known as biodiversity. It is a component of nature and it ensures the survival of human species by providing food, fuel, shelter, medicines. The richness of biodiversity depends on the conditions and area of the region. All species of plants taken together are known as flora and about 300,000 species of plants are known to date, all species of animals taken together are known as fauna which includes birds, mammals, fish, reptiles, insects, crustaceans, molluscs, etc. Rapid environmental changes typically cause mass extinctions, more than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earths current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described, the total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the mass of the biosphere has been estimated to be as much as 4 TtC. In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor of all living on Earth. The age of the Earth is about 4.54 billion years old, there are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a substance is graphite in 3.7 billion-year-old meta-sedimentary rocks discovered in Western Greenland. More recently, in 2015, remains of life were found in 4.1 billion-year-old rocks in Western Australia. According to one of the researchers, If life arose relatively quickly on Earth, then it could be common in the universe
9.
Disease
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A disease is a particular abnormal condition, a disorder of a structure or function, that affects part or all of an organism. The study of disease is called pathology which includes the study of cause, Disease is often construed as a medical condition associated with specific symptoms and signs. When caused by pathogens, even in the literature, the term disease is often misleadingly used in the place of its causal agent. This language habitat can cause confusion in the communication of the principle in epidemiology. Diseases can affect not only physically, but also emotionally. Death due to disease is called death by natural causes, there are four main types of disease, infectious diseases, deficiency diseases, genetic diseases, and physiological diseases. Diseases can also be classified as communicable and non-communicable, the deadliest diseases in humans are coronary artery disease, followed by cerebrovascular disease and lower respiratory infections. In many cases, terms such as disease, disorder, morbidity, there are situations, however, when specific terms are considered preferable. Disease The term disease broadly refers to any condition that impairs the normal functioning of the body, for this reason, diseases are associated with dysfunctioning of the bodys normal homeostatic processes. The term disease has both a count sense and a noncount sense, by contrast, an infection that is asymptomatic during its incubation period, but expected to produce symptoms later, is usually considered a disease. Non-infectious diseases are all other diseases, including most forms of cancer, heart disease, acquired disease disease that began at some point during ones lifetime, as opposed to disease that was already present at birth, which is congenital disease. Acquired sounds like it could mean caught via contagion, but it simply means acquired sometime after birth and it also sounds like it could imply secondary disease, but acquired disease can be primary disease. It is often, genetic and can be inherited and it can also be the result of a vertically transmitted infection from the mother such as HIV/AIDS. Genetic disease disease that is caused by genetic mutation and it is often inherited, but some mutations are random and de novo. Hereditary or inherited disease a type of disease caused by mutation that is hereditary Iatrogenic disease A disease condition caused by medical intervention. Idiopathic disease disease whose cause is unknown, as medical science has advanced, many diseases whose causes were formerly complete mysteries have been somewhat explained or even extensively explained. Bacterial infections can be primary or secondary to a viral infection or burn. Terminal disease disease with death as an inevitable result Illness Illness is generally used as a synonym for disease, however, this term is occasionally used to refer specifically to the patients personal experience of his or her disease
10.
Habitat destruction
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Habitat destruction is the process in which natural habitat is rendered unable to support the species present. In this process, the organisms that used the site are displaced or destroyed. Habitat destruction by human activity is mainly for the purpose of harvesting natural resources for production and urbanization. Clearing habitats for agriculture is the cause of habitat destruction. Other important causes of habitat destruction include mining, logging, trawling, habitat destruction is currently ranked as the primary cause of species extinction worldwide. Perhaps the greatest threat to organisms and biodiversity is the process of habitat loss, temple found that 82% of endangered bird species were significantly threatened by habitat loss. Endemic organisms with limited ranges are most affected by destruction, mainly because these organisms are not found anywhere else within the world. Many endemic organisms have very specific requirements for their survival that can only be found within a certain ecosystem, extinction may also take place very long after the destruction of habitat, a phenomenon known as extinction debt. Habitat destruction can also decrease the range of certain organism populations, one of the most famous examples is the impact upon Chinas giant panda, once found across the nation. Now it is found in fragmented and isolated regions in the southwest of the country. Biodiversity hotspots are chiefly tropical regions that feature high concentrations of species and. These hotspots are suffering from loss and destruction. Most of the habitat on islands and in areas of high human population density has already been destroyed. Islands suffering extreme habitat destruction include New Zealand, Madagascar, the Philippines, South and East Asia — especially China, India, Malaysia, Indonesia, and Japan — and many areas in West Africa have extremely dense human populations that allow little room for natural habitat. Marine areas close to highly populated coastal cities also face degradation of their coral reefs or other marine habitat and these areas include the eastern coasts of Asia and Africa, northern coasts of South America, and the Caribbean Sea and its associated islands. Regions of unsustainable agriculture or unstable governments, which may go hand-in-hand, central America, Sub-Saharan Africa, and the Amazonian tropical rainforest areas of South America are the main regions with unsustainable agricultural practices and/or government mismanagement. Areas of high agricultural output tend to have the highest extent of habitat destruction, in the U. S. less than 25% of native vegetation remains in many parts of the East and Midwest. Only 15% of land area remains unmodified by human activities in all of Europe, tropical rainforests have received most of the attention concerning the destruction of habitat
11.
Pollution
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Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution, Air pollution has always accompanied civilizations. Pollution started from prehistoric times when man created the first fires, metal forging appears to be a key turning point in the creation of significant air pollution levels outside the home. The burning of coal and wood, and the presence of horses in concentrated areas made the cities the cesspools of pollution. The Industrial Revolution brought an infusion of untreated chemicals and wastes into local streams that served as the water supply, king Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke became a problem. But the fuel was so common in England that this earliest of names for it was acquired because it could be carted away from some shores by the wheelbarrow and it was the industrial revolution that gave birth to environmental pollution as we know it today. London also recorded one of the extreme cases of water quality problems with the Great Stink on the Thames of 1858. Pollution issues escalated as population growth far exceeded view ability of neighborhoods to handle their waste problem, reformers began to demand sewer systems, and clean water. In 1870, the conditions in Berlin were among the worst in Europe. There were no toilets in the streets or squares. Visitors, especially women, often became desperate when nature called, in the public buildings the sanitary facilities were unbelievably primitive. As a metropolis, Berlin did not emerge from a state of barbarism into civilization until after 1870. Chicago and Cincinnati were the first two American cities to enact laws ensuring cleaner air in 1881, as historian Martin Melosi notes, The generation that first saw automobiles replacing the horses saw cars as miracles of cleanliness. By the 1940s, however, automobile-caused smog was an issue in Los Angeles. Other cities followed around the country early in the 20th century. Extreme smog events were experienced by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, Air pollution would continue to be a problem in England, especially later during the industrial revolution, and extending into the recent past with the Great Smog of 1952. Awareness of atmospheric pollution spread widely after World War II, with fears triggered by reports of fallout from atomic warfare. Then a non-nuclear event, The Great Smog of 1952 in London and this prompted some of the first major modern environmental legislation, The Clean Air Act of 1956
12.
Pesticide
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Pesticides are substances that are meant to control pests or weeds. The most common of these are herbicides which account for approximately 80% of all pesticide use, most pesticides are intended to serve as plant protection products, which in general, protect plants from weeds, fungi, or insects. In general, a pesticide is a chemical or biological agent that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes, although pesticides have benefits, some also have drawbacks, such as potential toxicity to humans and other species. According to the Stockholm Convention on Persistent Organic Pollutants,9 of the 12 most dangerous, the term includes substances intended for use as a plant growth regulator, defoliant, desiccant, or agent for thinning fruit or preventing the premature fall of fruit. Also used as substances applied to either before or after harvest to protect the commodity from deterioration during storage. Pesticides can be classified by target organism, chemical structure, biopesticides include microbial pesticides and biochemical pesticides. Plant-derived pesticides, or botanicals, have been developing quickly and these include the pyrethroids, rotenoids, nicotinoids, and a fourth group that includes strychnine and scilliroside. Many pesticides can be grouped into chemical families, prominent insecticide families include organochlorines, organophosphates, and carbamates. Organochlorine hydrocarbons could be separated into dichlorodiphenylethanes, cyclodiene compounds, and they operate by disrupting the sodium/potassium balance of the nerve fiber, forcing the nerve to transmit continuously. Their toxicities vary greatly, but they have phased out because of their persistence. Organophosphate and carbamates largely replaced organochlorines, both operate through inhibiting the enzyme acetylcholinesterase, allowing acetylcholine to transfer nerve impulses indefinitely and causing a variety of symptoms such as weakness or paralysis. Organophosphates are quite toxic to vertebrates, and have in some cases replaced by less toxic carbamates. Thiocarbamate and dithiocarbamates are subclasses of carbamates, prominent families of herbicides include phenoxy and benzoic acid herbicides, triazines, ureas, and Chloroacetanilides. Phenoxy compounds tend to selectively kill broad-leaf weeds rather than grasses, the phenoxy and benzoic acid herbicides function similar to plant growth hormones, and grow cells without normal cell division, crushing the plants nutrient transport system. Many commonly used pesticides are not included in these families, including glyphosate, Pesticides can be classified based upon their biological mechanism function or application method. Most pesticides work by poisoning pests, a systemic pesticide moves inside a plant following absorption by the plant. With insecticides and most fungicides, this movement is usually upward and outward, increased efficiency may be a result
13.
Introduced species
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Non-native species can have various effects on the local ecosystem. Introduced species that become established and spread beyond the place of introduction are called invasive species, some have a negative effect on a local ecosystem. Some introduced species may have no effect or only minor impact. Some species have been introduced intentionally to combat pests and they are called biocontrols and may be regarded as beneficial as an alternative to pesticides in agriculture for example. In some instances the potential for being beneficial or detrimental in the long run remains unknown, a list of some introduced species is given in a separate article. The effects of introduced species on natural environments have gained much scrutiny from scientists, governments, the terminology associated with introduced species is now in flux for various reasons. The term invasive refers only to those species that become established, for practical purposes, this term is applied only to invasive species that cause damage. With respect to plants, these latter are in this case defined as either ornamental or cultivated plants, also called an exotic or non-native species. Such species might be termed naturalized, established, wild non-native species, if they further spread beyond the place of introduction they are called invasive. The transition from introduction, to establishment and to invasion has been described in the context of plants, introduced species are essentially non-native species. Invasive species are introduced species that spreadwidely or quickly and cause harm, be that to the environment, human health. There have been calls from scientists to consider a species only in terms of their spread. According to a definition, an invasive species is one that has been introduced and become a pest in its new location. The term is used to both a sense of urgency and actual or potential harm. Executive Order 13112 defines invasive species as a species whose introduction does or is likely to cause economic or environmental harm or harm to human health. The biological definition of species, on the other hand, makes no reference to the harm they may cause. From a regulatory perspective, it is neither desirable nor practical to list as undesirable or outright ban all non-native species, regulations require a definitional distinction between non-natives that are deemed especially onerous and all others. Introduced pest species that are listed as invasive, best fit the definition of an invasive species
14.
Ultraviolet-B
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Ultraviolet is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the light output of the Sun. It is also produced by electric arcs and specialized lights, such as lamps, tanning lamps. Consequently, the effects of UV are greater than simple heating effects. Suntan, freckling and sunburn are familiar effects of over-exposure, along with risk of skin cancer. Living things on dry land would be damaged by ultraviolet radiation from the Sun if most of it were not filtered out by the Earths atmosphere. More-energetic, shorter-wavelength extreme UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground, Ultraviolet is also responsible for the formation of bone-strengthening vitamin D in most land vertebrates, including humans. The UV spectrum thus has both beneficial and harmful to human health. Ultraviolet rays are invisible to most humans, the lens in a human eye ordinarily filters out UVB frequencies or higher, and humans lack color receptor adaptations for ultraviolet rays. Under some conditions, children and young adults can see ultraviolet down to wavelengths of about 310 nm, near-UV radiation is visible to some insects, mammals, and birds. Small birds have a fourth color receptor for ultraviolet rays, this gives birds true UV vision, reindeer use near-UV radiation to see polar bears, who are poorly visible in regular light because they blend in with the snow. UV also allows mammals to see urine trails, which is helpful for animals to find food in the wild. The males and females of some species look identical to the human eye. Ultraviolet means beyond violet, violet being the color of the highest frequencies of visible light, Ultraviolet has a higher frequency than violet light. He called them oxidizing rays to emphasize chemical reactivity and to them from heat rays. The terms chemical and heat rays were eventually dropped in favour of ultraviolet and infrared radiation, in 1878 the effect of short-wavelength light on sterilizing bacteria was discovered. By 1903 it was known the most effective wavelengths were around 250 nm, in 1960, the effect of ultraviolet radiation on DNA was established. The discovery of the ultraviolet radiation below 200 nm, named vacuum ultraviolet because it is absorbed by air, was made in 1893 by the German physicist Victor Schumann
15.
Holocene extinction
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The large number of extinctions spans numerous families of plants and animals, including mammals, birds, amphibians, reptiles and arthropods. With widespread degradation of highly biodiverse habitats such as reefs and rainforest, as well as other areas. The Holocene extinction includes the disappearance of land animals known as megafauna. These extinctions, occurring near the Pleistocene–Holocene boundary, are referred to as the Quaternary extinction event. The arrival of humans on different continents coincides with megafaunal extinction, the most popular theory is that human overhunting of species added to existing stress conditions. Aside from humans, climate change may have been a factor in the megafaunal extinctions. The ecology of humanity has been noted as being that of an unprecedented global superpredator that regularly preys on the adults of other predators and has worldwide effects on food webs. Extinctions of species have occurred on every land mass and ocean, with famous examples within Africa, Asia, Europe, Australia, North and South America. Overall, the Holocene extinction can be characterized by the impact on the environment. A ballooning human population along with profligate consumption are considered to be the drivers of this rapid decline. In many cases, it is suggested even minimal hunting pressure was enough to wipe out large fauna, only during the most recent parts of the extinction have plants also suffered large losses. In The Future of Life, E. O. Wilson of Harvard calculated that, if the current rate of human disruption of the biosphere continues, one-half of Earths higher lifeforms will be extinct by 2100. A1998 poll conducted by the American Museum of Natural History found that seventy percent of biologists acknowledge the existence of the anthropogenic extinction. Numerous scientific studies — such as a 2004 report published in Nature and it is also the only known mass extinction of plants. One scientist estimates the current extinction rate may be 10,000 times the background extinction rate, nevertheless, most scientists predict a much lower extinction rate than this outlying estimate. Stuart Pimm stated the current rate of extinction is about 100 times the natural rate for plants. Mass extinctions are characterized by the loss of at least 75% of species within a short period of time. In a pair of studies published in 2015, extrapolation from observed extinction of Hawaiian snails led to the conclusion that 7% of all species on Earth may have been lost already
16.
Class (biology)
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In biological classification, class is, a taxonomic rank. Other well-known ranks in descending order of size are life, domain, kingdom, phylum, order, family, genus, as for the other well-known ranks, there is the option of an immediately lower rank, indicated by the prefix sub-, subclass. A taxonomic unit, a taxon, in that rank, in that case the plural is classes The composition of each class is determined by a taxonomist. Often there is no agreement, with different taxonomists taking different positions. There are no rules that a taxonomist needs to follow in describing a class. For example, dogs are assigned to the phylum Chordata, in the class Mammalia. In botany, classes are now rarely discussed, for some clades, a number of alternative classifications are used. In the first edition of his Systema Naturae, carl Linnaeus divided all three of his kingdoms of Nature into classes. The class was considered the highest level of the hierarchy until George Cuviers embranchements. Cladistics List of animal classes Phylogenetics Systematics Taxonomy
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Frog
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A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura. The oldest fossil proto-frog appeared in the early Triassic of Madagascar, Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforests. There are approximately 4,800 recorded species, accounting for over 85% of extant amphibian species and they are also one of the five most diverse vertebrate orders. The body plan of a frog is generally characterized by a stout body, protruding eyes, cleft tongue, limbs folded underneath. Besides living in water and on dry land, the adults of some species are adapted for living underground or in trees. The skin of the frog is glandular, with secretions ranging from distasteful to toxic, Frogs skins vary in colour from well-camouflaged dappled brown, grey and green to vivid patterns of bright red or yellow and black to advertise toxicity and warn off predators. Frogs typically lay their eggs in water, the eggs hatch into aquatic larvae called tadpoles that have tails and internal gills. They have highly specialized rasping mouth parts suitable for herbivorous, omnivorous or planktivorous diets, the life cycle is completed when they metamorphose into adults. A few species deposit eggs on land or bypass the tadpole stage, adult frogs generally have a carnivorous diet consisting of small invertebrates, but omnivorous species exist and a few feed on fruit. Frogs are extremely efficient at converting what they eat into body mass and they are an important food source for predators and part of the food web dynamics of many of the worlds ecosystems. The skin is semi-permeable, making them susceptible to dehydration, so they live in moist places or have special adaptations to deal with dry habitats. Frogs are valued as food by humans and also have many roles in literature, symbolism. Frog populations have declined significantly since the 1950s, more than one third of species are considered to be threatened with extinction and over one hundred and twenty are believed to have become extinct since the 1980s. The number of malformations among frogs is on the rise and a fungal disease. Conservation biologists are working to understand the causes of these problems, the name frog derives from Old English frogga, abbreviated to frox, forsc, and frosc, probably deriving from Proto-Indo-European preu = to jump. About 88% of amphibian species are classified in the order Anura and these include around 4,810 species in 33 families, of which the Leptodactylidae, Hylidae and Ranidae are the richest in species. The use of the common frog and toad has no taxonomic justification. From a classification perspective, all members of the order Anura are frogs, there are numerous exceptions to this rule
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Toad
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Toad is a common name applied to certain frogs, especially of the family Bufonidae, that are characterized by dry, leathery skin, short legs, and parotoid glands. In scientific taxonomy, toads are found in the families Bufonidae, Bombinatoridae, Discoglossidae, Pelobatidae, Rhinophrynidae, Scaphiopodidae, usually the largest of the bumps on the skin of a toad are those that cover the parotoid glands. The bumps are commonly called warts, but they have nothing to do with infectious warts, being fixed in size, present on healthy specimens, frogs travel from non-breeding areas to breeding areas of ponds and lakes. Bogert suggests that the call of the toads is the most important cue used by toads in the homing to ponds, toads, like many amphibians, exhibit breeding site fidelity. Individual Bufo americanus toads return to their natal ponds to breed where they are likely to encounter siblings as potential mates, although inbred examples within a species is possible, siblings rarely mate. Toads recognize and actively avoid mating with close kin, advertisement vocalizations given by males appear to serve as cues by which females recognize kin. Kin recognition thus allows avoidance of inbreeding and consequent inbreeding depression, in Kenneth Grahames 1908 novel The Wind in the Willows, Mr. Toad is a likeable and popular, if selfish and narcissistic, comic character. Mr. Toad reappears as the character in A. A. Milnes 1929 play Toad of Toad Hall. In Chinese culture, the Money Toad Jin Chan appears as a Feng Shui charm for prosperity. There is no definitive collective noun for toads, and like most collective nouns, true toad Common toad Chisholm, Hugh, ed. Toad
19.
Salamander
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All present-day salamander families are grouped together under the scientific name Urodela. Salamander diversity is most abundant in the Northern Hemisphere and most species are found in the Holarctic ecozone, Salamanders never have more than four toes on their front legs and five on their rear legs, but some species have fewer digits and others lack hind limbs. Their permeable skin usually makes them reliant on habitats in or near water or other cool, some salamander species are fully aquatic throughout their lives, some take to the water intermittently, and others are entirely terrestrial as adults. Unique among vertebrates, they are capable of regenerating lost limbs, members of the family Salamandridae are mostly known as newts and lack the costal grooves along the sides of their bodies typical of other groups. The skin of some species contains the poison tetrodotoxin and these salamanders tend to be slow-moving and have bright warning coloration to advertise their toxicity. Salamanders typically lay eggs in water and have aquatic larvae, in some species and some harsh environments, salamanders reproduce while still in the larval state. In literature and legend, the salamander is associated with fire, being supposedly unharmed by the flames, more plausibly, salamanders were said to be intensely poisonous. Despite this, salamander brandy, a prepared by dunking live salamanders in fermenting fruit juices, is reputed to have hallucinogenic. The skin lacks scales and is moist and smooth to the touch, except in newts of the Salamandridae, the skin may be drab or brightly colored, exhibiting various patterns of stripes, bars, spots, blotches, or dots. Male newts become dramatically colored during the breeding season, cave species dwelling in darkness lack pigmentation and have a translucent pink or pearlescent appearance. Salamanders range in size from the minute salamanders, with a length of 2.7 cm, including the tail, to the Chinese giant salamander which reaches 1.8 m. Most, however, are between 10 and 20 cm in length, an adult salamander generally resembles a small lizard, having a basal tetrapod body form with a cylindrical trunk, four limbs, and a long tail. Their function seems to be to keep the skin moist by channeling water over the surface of the body. The feet are broad with short digits, usually four on the front feet, Salamanders do not have claws, and the shape of the foot varies according to the animals habitat. Climbing species have elongated, square-tipped toes, while rock-dwellers have larger feet with short, when ascending, the tail props up the rear of the body, while one hind foot moves forward and then swings to the other side to provide support as the other hind foot advances. In larvae and aquatic salamanders, the tail is flattened, has dorsal and ventral fins. In the families Ambystomatidae and Salamandridae, the tail, which is larger than that of the female, is used during the amplexus embrace to propel the mating couple to a secluded location. In terrestrial species, the moves to counterbalance the animal as it runs, while in the arboreal salamander and other tree-climbing species
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Newt
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A newt is a salamander in the subfamily Pleurodelinae, also called eft during its terrestrial juvenile phase. Unlike other members of the family Salamandridae, newts are semiaquatic, not all aquatic salamanders are considered newts, however. The more than 100 known species of newts are found in North America, Europe, North Africa, newts metamorphose through three distinct developmental life stages, aquatic larva, terrestrial juvenile, and adult. Adult newts have lizard-like bodies and return to the every year to breed, otherwise living in humid. Newts are threatened by loss, fragmentation and pollution. Several species are endangered, and at least one species, the Yunnan lake newt, has gone extinct recently, the Old English name of the animal was efte, efeta, resulting in Middle English eft, this word was transformed irregularly into euft, evete, or ewt. The initial n was added from the article an by provection by the early 15th century. The form newt appears to have arisen as a variant of eft in Staffordshire. Dialectal English and Scots also has the word ask used for both newts and wall lizards, from Old English āþexe, from Proto-Germanic *agiþahsijǭ, literally lizard-badger or distaff-like lizard. Latin had the name stellio for a type of spotted newt, ancient Greek had the name κορδύλος, presumably for the water newt. German has Molch, from Middle High German mol, wikt, olm, newts are also known as Tritones in historical literature, and triton remains in use as common name in some Romance languages, in Greek, in Russian and Serbian. The systematic name Tritones was introduced alongside Pleurodelinae by Tschudi in 1838, laurentis Triton was renamed to Triturus by Rafinesque in 1815. Tschudis Pleurodelinae is based on the type genus Pleurodeles named by Michahelles in 1830, newts are found in North America, Europe, North Africa and Asia. Eastern Asia, from Eastern India over Indochina to Japan, is home to five genera with more than 40 species, newts are semi-aquatic, spending part of the year in the water for reproduction and the rest of the year on land. While most species prefer stagnant water bodies such as ponds, ditches or flooded meadows for reproduction, the European brook newts and European mountain newts have even adapted to life in cold, oxygen-rich mountain streams. During their terrestrial phase, newts live in habitats with abundandant cover such as logs, rocks. Newts share many of the characteristics of their kin, Caudata, including semipermeable glandular skin, four equal-sized limbs. The newts skin, however, is not as smooth as that of other salamanders, aquatic larvae have true teeth on both upper and lower jaws, and external gills
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Caecilian
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Caecilians are a group of limbless, serpentine amphibians. They mostly live hidden in the ground, making them the least familiar order of amphibians, all modern caecilians and their closest fossil relatives are grouped as a clade, Apoda, within the larger group Gymnophiona, which also includes more primitive extinct caecilian-like amphibians. Caecilians are mostly distributed in the tropics of South and Central America, Africa, the diets consists of earthworms and small subterranean creatures. Caecilians completely lack limbs, making the species resemble worms, while the larger species, with lengths up to 1.5 m. Their tails are short or absent, and their cloacae are near the ends of their bodies and their skin is smooth and usually dark, but some species have colorful skins. Inside the skin are calcite scales, the skin also has numerous ring-shaped folds, or annuli, that partially encircle the body, giving them a segmented appearance. Like some other living amphibians, the skin contains glands that secrete a toxin to deter predators, the skin secretions of Siphonops paulensis have been shown to have hemolytic properties. Caecilians vision is limited to perception, and their anatomy is highly adapted for a burrowing lifestyle. They have a skull, with a pointed snout used to force their way through soil or mud. In most species, the bones in the skull are reduced in number and fused together, and their muscles are adapted to pushing their way through the ground, with the skeleton and deep muscles acting as a piston inside the skin and outer muscles. This allows the animal to anchor its hind end in position, and force the head forwards, in water or very loose mud, caecilians instead swim in an eel-like fashion. Caecilians in the family Typhlonectidae are aquatic, and the largest of their kind, the representatives of this family have a fleshy fin running along the rear section of their bodies, which enhances propulsion in water. All but the most primitive caecilians have two sets of muscles for closing the jaw, compared with the pair found in other creatures. These are more developed in the most efficient burrowers among the caecilians. Adapting to their life, the eyes are small and covered by skin for protection. This is not strictly true, although their sight is limited to simple dark-light perception, all caecilians possess a pair of tentacles, located between their eyes and nostrils. These are probably used for a second olfactory capability, in addition to the sense of smell based in the nose. The middle ear consists of only the stapes and the oval window, the species within the Scolecomorphidae lack both stapes and an oval window, making them the only known amphibians missing all the components of a middle ear apparatus
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IUCN Red List
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The IUCN Red List of Threatened Species, founded in 1964, is the worlds most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the main authority on the conservation status of species. A series of Regional Red Lists are produced by countries or organizations, the IUCN Red List is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world, the aim is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to try to reduce species extinction. Major species assessors include BirdLife International, the Institute of Zoology, the World Conservation Monitoring Centre, collectively, assessments by these organizations and groups account for nearly half the species on the Red List. The IUCN aims to have the category of every species re-evaluated every five years if possible, the 1964 IUCN Red List of Threatened Plants used the older pre-criteria Red List assessment system. Plants listed may not, therefore, appear in the current Red List, IUCN advise that is best to check both the online Red List and the 1997 plants Red List publication. The 2006 Red List, released on 4 May 2006 evaluated 40,168 species as a whole, plus an additional 2,160 subspecies, varieties, aquatic stocks, on 12 September 2007, the World Conservation Union released the 2007 IUCN Red List of Threatened Species. Russ Mittermeier, chief of Swiss-based IUCNs Primate Specialist Group, stated that 16,306 species are endangered with extinction,188 more than in 2006, the Red List includes the Sumatran orangutan in the Critically Endangered category and the Bornean orangutan in the Endangered category. The study shows at least 1,141 of the 5,487 mammals on Earth are known to be threatened with extinction, and 836 are listed as Data Deficient. The Red List of 2012 was released 19 July 2012 at Rio+20 Earth Summit, nearly 2,000 species were added, the IUCN assessed a total of 63,837 species which revealed 19,817 are threatened with extinction. With 3,947 described as endangered and 5,766 as endangered. At threat are 41% of amphibian species, 33% of reef-building corals, 30% of conifers, 25% of mammals, the IUCN Red List has listed 132 species of plants and animals from India as Critically Endangered. Extinct – No known individuals remaining, extinct in the wild – Known only to survive in captivity, or as a naturalized population outside its historic range. Critically endangered – Extremely high risk of extinction in the wild, Endangered – High risk of extinction in the wild. Vulnerable – High risk of endangerment in the wild, near threatened – Likely to become endangered in the near future. Does not qualify for a more at-risk category, widespread and abundant taxa are included in this category. Data deficient – Not enough data to make an assessment of its risk of extinction, Not evaluated – Has not yet been evaluated against the criteria
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Critically Endangered
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A critically endangered species is one which has been categorized by the International Union for Conservation of Nature as facing a very high risk of extinction in the wild. Its the highest risk category assigned by the IUCN Red List for wild species, as of 2014, there are 2464 animal and 2104 plant species with this assessment, compared with 1998 levels of 854 and 909, respectively. As the IUCN Red List does not consider a species extinct until extensive, targeted surveys have been conducted, IUCN maintains a list of possibly extinct CR and possibly extinct in the wild CR species, modelled on categories used by BirdLife International to categorize these taxa. To be defined as critically endangered in the Red List, a species must meet any of the criteria, A, Occurring over less than 100 km². Severe habitat fragmentation or existing at just one location 2, decline in extent of occurrence, area of occupancy, area/extent/quality of habitat, number of locations/subpopulations, or amount of MI.3. Extreme fluctuations in extent of occurrence, area of occupancy, number of locations/subpopulations, B, As above, but less than 10 km². C, Declining population of less than 250 MI and either,1, a decline of 25% over 3G/10Y,2. Extreme fluctuations, or over 90% of MI in a single subpopulation, D, Numbers less than 50 MI. E, At least 50% chance of going Extinct in the Wild over 3G/10Y, lists of IUCN Red List Critically Endangered species for lists ordered by taxonomic rank. IUCN Red List of Threatened Species, International Union for Conservation of Nature. The Criteria for Critically Endangered, IUCN
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United States
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Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
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Central America
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Central America is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. Central America is bordered by Mexico to the north, Colombia to the southeast, the Caribbean Sea to the east, Central America consists of seven countries, Belize, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama. The combined population of Central America is between 41,739,000 and 42,688,190, Central America is a part of the Mesoamerican biodiversity hotspot, which extends from northern Guatemala through to central Panama. Due to the presence of several active faults and the Central America Volcanic Arc. Volcanic eruptions and earthquakes occur frequently, these disasters have resulted in the loss of many lives. In the Pre-Columbian era, Central America was inhabited by the peoples of Mesoamerica to the north and west. Soon after Christopher Columbuss voyages to the Americas, the Spanish began to colonize the Americas, the seven states finally became independent autonomous states, beginning with Nicaragua, Honduras, Costa Rica, and Guatemala, followed by El Salvador, then Panama, and finally Belize. Middle America is usually thought to comprise Mexico to the north of the 7 states of Central America as well as Colombia, usually the whole of the Caribbean to the north-east and sometimes the Guyanas are also included. According to one source, the term Central America was used as a synonym for Middle America as recently as 1962, in Brazil, Central America comprises all countries between Mexico and Colombia, including those in the Caribbean. Mexico, in whole or in part, is included by British people. For the people living in the 5 countries formerly part of the Federal Republic of Central America there is a distinction between the Spanish language terms América Central and Centroamérica, in the Pre-Columbian era, the northern areas of Central America were inhabited by the indigenous peoples of Mesoamerica. Most notable among these were the Mayans, who had built numerous cities throughout the region, and the Aztecs, following Christopher Columbuss voyages to the Americas, the Spanish sent many expeditions to the region, and they began their conquest of Maya territory in 1523. Soon after the conquest of the Aztec Empire, Spanish conquistador Pedro de Alvarado commenced the conquest of northern Central America for the Spanish Empire. Beginning with his arrival in Soconusco in 1523, Alvarados forces systematically conquered and subjugated most of the major Maya kingdoms, including the Kiche, Tzutujil, Pipil, and the Kaqchikel. By 1528, the conquest of Guatemala was nearly complete, with only the Petén Basin remaining outside the Spanish sphere of influence, the last independent Maya kingdoms – the Kowoj and the Itza people – were finally defeated in 1697, as part of the Spanish conquest of Petén. In 1538, Spain established the Real Audiencia of Panama, which had jurisdiction over all land from the Strait of Magellan to the Gulf of Fonseca. This entity was dissolved in 1543, and most of the territory within Central America then fell under the jurisdiction of the Audiencia Real de Guatemala. This area included the current territories of Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and the Mexican state of Chiapas, the president of the Audiencia, which had its seat in Antigua Guatemala, was the governor of the entire area
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South America
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South America is a continent located in the western hemisphere, mostly in the southern hemisphere, with a relatively small portion in the northern hemisphere. It may also be considered a subcontinent of the Americas, which is the used in nations that speak Romance languages. The reference to South America instead of other regions has increased in the last decades due to changing geopolitical dynamics. It is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean, North America and it includes twelve sovereign states, a part of France, and a non-sovereign area. In addition to this, the ABC islands of the Kingdom of the Netherlands, Trinidad and Tobago, South America has an area of 17,840,000 square kilometers. Its population as of 2005 has been estimated at more than 371,090,000, South America ranks fourth in area and fifth in population. Brazil is by far the most populous South American country, with more than half of the population, followed by Colombia, Argentina, Venezuela. In recent decades Brazil has also concentrated half of the regions GDP and has become a first regional power, most of the population lives near the continents western or eastern coasts while the interior and the far south are sparsely populated. Most of the continent lies in the tropics, the continents cultural and ethnic outlook has its origin with the interaction of indigenous peoples with European conquerors and immigrants and, more locally, with African slaves. Given a long history of colonialism, the majority of South Americans speak Portuguese or Spanish. South America occupies the portion of the Americas. The continent is delimited on the northwest by the Darién watershed along the Colombia–Panama border. Almost all of mainland South America sits on the South American Plate, South Americas major mineral resources are gold, silver, copper, iron ore, tin, and petroleum. These resources found in South America have brought high income to its countries especially in times of war or of rapid growth by industrialized countries elsewhere. However, the concentration in producing one major export commodity often has hindered the development of diversified economies and this is leading to efforts to diversify production to drive away from staying as economies dedicated to one major export. South America is one of the most biodiverse continents on earth, South America is home to many interesting and unique species of animals including the llama, anaconda, piranha, jaguar, vicuña, and tapir. The Amazon rainforests possess high biodiversity, containing a proportion of the Earths species. Brazil is the largest country in South America, encompassing around half of the land area
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Australia
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Australia, officially the Commonwealth of Australia, is a country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. It is the worlds sixth-largest country by total area, the neighbouring countries are Papua New Guinea, Indonesia and East Timor to the north, the Solomon Islands and Vanuatu to the north-east, and New Zealand to the south-east. Australias capital is Canberra, and its largest urban area is Sydney, for about 50,000 years before the first British settlement in the late 18th century, Australia was inhabited by indigenous Australians, who spoke languages classifiable into roughly 250 groups. The population grew steadily in subsequent decades, and by the 1850s most of the continent had been explored, on 1 January 1901, the six colonies federated, forming the Commonwealth of Australia. Australia has since maintained a liberal democratic political system that functions as a federal parliamentary constitutional monarchy comprising six states. The population of 24 million is highly urbanised and heavily concentrated on the eastern seaboard, Australia has the worlds 13th-largest economy and ninth-highest per capita income. With the second-highest human development index globally, the country highly in quality of life, health, education, economic freedom. The name Australia is derived from the Latin Terra Australis a name used for putative lands in the southern hemisphere since ancient times, the Dutch adjectival form Australische was used in a Dutch book in Batavia in 1638, to refer to the newly discovered lands to the south. On 12 December 1817, Macquarie recommended to the Colonial Office that it be formally adopted, in 1824, the Admiralty agreed that the continent should be known officially as Australia. The first official published use of the term Australia came with the 1830 publication of The Australia Directory and these first inhabitants may have been ancestors of modern Indigenous Australians. The Torres Strait Islanders, ethnically Melanesian, were originally horticulturists, the northern coasts and waters of Australia were visited sporadically by fishermen from Maritime Southeast Asia. The first recorded European sighting of the Australian mainland, and the first recorded European landfall on the Australian continent, are attributed to the Dutch. The first ship and crew to chart the Australian coast and meet with Aboriginal people was the Duyfken captained by Dutch navigator, Willem Janszoon. He sighted the coast of Cape York Peninsula in early 1606, the Dutch charted the whole of the western and northern coastlines and named the island continent New Holland during the 17th century, but made no attempt at settlement. William Dampier, an English explorer and privateer, landed on the north-west coast of New Holland in 1688, in 1770, James Cook sailed along and mapped the east coast, which he named New South Wales and claimed for Great Britain. The first settlement led to the foundation of Sydney, and the exploration, a British settlement was established in Van Diemens Land, now known as Tasmania, in 1803, and it became a separate colony in 1825. The United Kingdom formally claimed the part of Western Australia in 1828. Separate colonies were carved from parts of New South Wales, South Australia in 1836, Victoria in 1851, the Northern Territory was founded in 1911 when it was excised from South Australia
28.
Fiji
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Fiji, officially the Republic of Fiji, is an island country in Melanesia in the South Pacific Ocean about 1,100 nautical miles northeast of New Zealands North Island. Fiji is an archipelago of more than 330 islands, of which 110 are permanently inhabited, the two major islands, Viti Levu and Vanua Levu, account for 87% of the population of almost 860,000. The capital, Suva on Viti Levu, serves as Fijis principal cruise port, about three-quarters of Fijians live on Viti Levus coasts, either in Suva or in smaller urban centres like Nadi or Lautoka. Viti Levus interior is sparsely inhabited due to its terrain, Fiji has one of the most developed economies in the Pacific due to an abundance of forest, mineral, and fish resources. Today, the sources of foreign exchange are its tourist industry. The countrys currency is the Fijian dollar, Fijis local government, in the form of city and town councils, is supervised by the Ministry of Local Government and Urban Development. The majority of Fijis islands were formed through volcanic activity starting around 150 million years ago, today, some geothermal activity still occurs on the islands of Vanua Levu and Taveuni. Fiji has been inhabited since the second millennium BC, and was settled first by Austronesians and later by Melanesians, Europeans visited Fiji from the 17th century, and, after a brief period as an independent kingdom, the British established the Colony of Fiji in 1874. Fiji was a Crown colony until 1970, when it gained independence as a Commonwealth realm, a republic was declared in 1987, following a series of coups détat. In a coup in 2006, Commodore Frank Bainimarama seized power, later in 2009, Iloilo was replaced as President by Ratu Epeli Nailatikau. After years of delays, an election was held on 17 September 2014. Bainimaramas FijiFirst party won with 59. 2% of the vote, Fijis main island is known as Viti Levu and it is from this that the name Fiji is derived, though the common English pronunciation is based on that of their island neighbours in Tonga. Its emergence can be described as follows, Fijians first impressed themselves on European consciousness through the writings of the members of the expeditions of Cook who met them in Tonga. They were described as warriors and ferocious cannibals, builders of the finest vessels in the Pacific. They inspired awe amongst the Tongans, and all their Manufactures, especially bark cloth and clubs, were highly valued and much in demand. They called their home Viti, but the Tongans called it Fisi, and it was by this foreign pronunciation, Fiji, first promulgated by Captain James Cook, that these islands are now known. Feejee, the Anglicised spelling of the Tongan pronunciation, was used in accounts and other writings until the late 19th century, by missionaries and other travellers visiting Fiji. Pottery art from Fijian towns shows that Fiji was settled before or around 3500 to 1000 BC, the first settlements in Fiji were started by voyaging traders and settlers from the west about 5000 years ago
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Aquatic animal
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An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, natural environments and the animals that live in them can be categorized as aquatic or terrestrial. The term aquatic can in theory be applied to animals that live in fresh water or salt water. However, the marine is most commonly used for animals that live in saltwater, i. e. in oceans, seas. Aquatic animals are often of concern to conservationists because of the fragility of their environments. Aquatic animals are subject to pressure from overfishing, destructive fishing, marine pollution, the term aquatic mammal is also applied to four-footed mammals like the river otter and beavers, although these are technically amphibious. Amphibians, like frogs, while requiring water, are separated into their own environmental classification, the majority of amphibians have an aquatic larval stage, like a tadpole, but then live as terrestrial adults, and may return to the water to mate. Certain fish also evolved to breathe air to survive oxygen-deprived water, such as arapaima, Aquatic mammal Aquatic plant Freshwater snail List of semiaquatic tetrapods Marine biology Marine invertebrates Marine mammal Annelids
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Larva
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A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a phase of their life cycle. The larvas appearance is very different from the adult form. A larva often has unique structures and organs that do not occur in the adult form and their diet may also be considerably different. Larvae are frequently adapted to separate from adults. For example, some such as tadpoles live almost exclusively in aquatic environments. By living in an environment, larvae may be given shelter from predators. Animals in the stage will consume food to fuel their transition into the adult form. In some species like barnacles, adults are immobile but their larvae are mobile, some larvae are dependent on adults to feed them. In many eusocial Hymenoptera species, the larvae are fed by female workers, in Ropalidia marginata the males are also capable of feeding larvae but they are much less efficient, spending more time and getting less food to the larvae. The larvae of species can become pubescent and do not develop further into the adult form. This is a type of neoteny and it is a misunderstanding that the larval form always reflects the groups evolutionary history. This could be the case, but often the stage has evolved secondarily. In these cases the form may differ more than the adult form from the groups common origin. Within Insects, only Endopterygotes show different types of larvae, several classifications have been suggested by many entomologists, and following classification is based on Antonio Berlese classification in 1913. There are four types of endopterygote larvae types, Apodous larvae - no legs at all and are poorly sclerotized. Based on sclerotization, three forms are recognized. Eucephalous - with well sclerotized head capsule, found in Nematocera, Buprestidae and Cerambycidae families
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Terrestrial animal
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Terrestrial invertebrates include ants, flies, crickets, grasshoppers and snails. The term terrestrial is typically applied for species that live primarily on the ground, in contrast to arboreal species, there are other less common terms that apply to specific groups of terrestrial animals, Saxicolous are rock dwelling creatures. Saxicolus is derived from the Latin word Saxum which means Rocks, arenicolous creatures live in the sand. Terrestrial invasion is one of the most important events in the history of life, Terrestrial lineages evolved in several animal phyla, among which vertebrates, arthropods, and mollusks are representatives of more successful groups of terrestrial animals. Terrestrial animals do not form a clade, rather, they share only the fact that they live on land. The transition from an aquatic to terrestrial life has evolved independently and successfully many times by groups of animals. Most terrestrial lineages originated under a mild or tropical climate during the Paleozoic and Mesozoic, roundworms, tardigrades, and rotifers are microscopic animals that require a film of water to live in, and are not considered truly terrestrial. Flatworms, ribbon worms, velvet worms and annelids all depend on more or less moist habitats, labeling an animal species terrestrial or aquatic is often obscure and becomes a matter of judgment. Many animals considered terrestrial have a life-cycle that is dependent on being in water. Penguins, seals, and walruses sleep on land and feed in the ocean, there are crab species that are completely aquatic, crab species that are amphibious, and crab species that are terrestrial. Fiddler crabs are called semi-terrestrial since they make burrows in the muddy substrate, when the tide is out, fiddler crabs search the beach for food. The same is true in the Mollusca, many hundreds of genera and species live in intermediate situations, such as for example. Some gastropods with gills live on land, and others with a live in the water. As well as the terrestrial and the purely aquatic animals. There are no universally accepted criteria for deciding how to label these species, fossil evidence has shown that sea creatures, likely related to arthropods, first began to make forays on to land around 530 million years ago. There is little reason to believe, however, that animals first began living reliably on land around this time period. A more likely hypothesis is that these early arthropods motivation for venturing on to dry land was to mate or lay out of the reach of predators. As such, they are likely the most recent common ancestor of all modern tetrapods, gastropod mollusks are one of the most successful animals that have diversified in the fully terrestrial habitat
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Adult
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Biologically, an adult is a human or other organism that has reached sexual maturity. In human context, the term adult additionally has meanings associated with social and legal concepts, in contrast to a minor, a legal adult is a person who has attained the age of majority and is therefore regarded as independent, self-sufficient, and responsible. Human adulthood encompasses psychological adult development, conversely, one may legally be an adult but possess none of the maturity and responsibility that may define an adult character. In different cultures there are events that relate passing from being a child to becoming an adult or coming of age. This often encompasses the passing a series of tests to demonstrate that a person is prepared for adulthood, or reaching a specified age, most modern societies determine legal adulthood based on reaching a legally specified age without requiring a demonstration of physical maturity or preparation for adulthood. Historically and cross-culturally, adulthood has been determined primarily by the start of puberty, in the past, a person usually moved from the status of child directly to the status of adult, often with this shift being marked by some type of coming-of-age test or ceremony. After the social construct of adolescence was created, adulthood split into two forms, biological adulthood and social adulthood, thus, there are now two primary forms of adults, biological adults and social adults. Depending on the context, adult can indicate either definition, thus, the base definition of the word adult is the period beginning at puberty. Puberty generally begins around 10 or 11 years of age for girls and 11 or 12 years of age for boys, legally, adulthood means that one can engage in a contract. One can distinguish the legality of acts of a person, or of enabling a young person to carry out that act, by selling, renting out, showing, permitting entrance, allowing participation. There may be distinction between commercially and socially enabling, sometimes there is the requirement of supervision by a legal guardian, or just by an adult. Sometimes there is no requirement, but rather a recommendation, with regard to films with violence, etc. Some cultures in Africa define adulthood at age 13, according to Jewish tradition, adulthood is reached at age 13 for Jewish boys and girls, they are expected to demonstrate preparation for adulthood by learning the Torah and other Jewish practices. The Christian Bible and Jewish scripture contain no age requirement for adulthood or marrying, which includes engaging in sexual activity. The 1983 Code of Canon Law states, A man before he has completed his year of age
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Aquatic ecosystem
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An aquatic ecosystem is an ecosystem in a body of water. Communities of organisms that are dependent on other and on their environment live in aquatic ecosystems. The two main types of ecosystems are marine ecosystems and freshwater ecosystems. Marine ecosystems cover approximately 71% of the Earths surface and contain approximately 97% of the planets water and they generate 32% of the worlds net primary production. They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts, approximately 85% of the dissolved materials in seawater are sodium and chlorine. Seawater has a salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems, marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, the benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides, in this figure it is termed the littoral zone, other near-shore zones can include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web, classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Fishes caught in marine ecosystems are the biggest source of commercial foods obtained from wild populations, environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources, marine pollution, climate change, and building on coastal areas. Freshwater ecosystems cover 0. 78% of the Earths surface and inhabit 0. 009% of its total water and they generate nearly 3% of its net primary production. Freshwater ecosystems contain 41% of the known fish species. There are three types of freshwater ecosystems, Lentic, slow moving water, including pools, ponds. Lotic, faster moving water, for example streams and rivers, wetlands, areas where the soil is saturated or inundated for at least part of the time. Lake ecosystems can be divided into zones, one common system divides lakes into three zones. The first, the zone, is the shallow zone near the shore. This is where rooted wetland plants occur, the offshore is divided into two further zones, an open water zone and a deep water zone
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Sentinel species
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Sentinel species are organisms, often animals, used to detect risks to humans by providing advance warning of a danger. The terms primarily apply in the context of environmental hazards rather than those other sources. Some animals can act as sentinels because they may be more susceptible or have greater exposure to a hazard than humans in the same environment. People have long observed animals for signs of impending hazards or evidence of environmental threats, plants and other living organisms have also been used for these purposes. There are countless examples of effects on animals that later manifested in humans. The classic example is the canary in the coal mine, the idea of placing a canary or other warm blooded animal in a mine to detect carbon monoxide was first proposed by John Scott Haldane, in 1913 or later. Well into the 20th century, coal miners brought canaries into coal mines as a signal for toxic gases. The birds, being sensitive, would become sick before the miners. In Minamata Bay, Japan, cats developed dancing cat fever before humans were affected due to eating mercury-contaminated fish, dogs were recognized as early as 1939 to be more susceptible to tonsil cancer if they were kept in crowded urban environments. Studies similarly found higher rates in animals exposed to tobacco smoke. Yushō disease was discovered when poultry began dying at alarming rates due to polychlorinated biphenyl poisoning. Animal sentinels must have measurable responses to the hazard in question, whether that is due to the death, disappearance. Many of these species are ideally unendangered and easy to handle and it is important that the species range overlap with the range being studied. Often the ideal species is determined by the characteristics of the hazard, for example, honey bees are susceptible to air pollution. Similarly both bats and swallows have been used to monitor pesticide contamination due to their diet of insects that may have been affected by the chemicals, by the same token, aquatic animals, or their direct predators, are used as sentinel species to monitor water pollution. Some species may show effects of a contaminant before humans due to their size, their reproductive rate, canaries were iconically used in coal mines to detect the presence of carbon monoxide. The birds rapid breathing rate, small size, and high metabolism, compared to the miners, led birds in dangerous mines to succumb before the miners, a number of animals have been used to measure varying kinds of air pollution. These include honey bees for air pollution, bivalve molluscs for online water-quality survey, bats and swallows have been used to monitor pesticide contamination due to their diet of insects that may have been affected by the chemicals
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Herpetology
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Herpetology is the branch of zoology concerned with the study of amphibians and reptiles. Batrachology is a subdiscipline of herpetology concerned with the study of amphibians alone. Herpetology is concerned with poikilothermic, ectothermic tetrapods, one of the most prestigious organizations, the American Society of Ichthyologists and Herpetologists, is an example of this. Many herpetological societies exist today, having been formed to promote interest in reptiles, some toxins and venoms produced by reptiles and amphibians are useful in human medicine. Currently, some snake venom has been used to create anti-coagulants that work to treat stroke victims, the word herpetology is from Greek, ἑρπετόν, herpeton, creeping animal and -λογία, -logia, knowledge. People with an avid interest in herpetology and who keep different reptiles or amphibians often refer to themselves as herpers, herp is a vernacular term for reptiles and amphibians. It is derived from the old term herpetile, with back to Linnaeuss classification of animals, in which he grouped reptiles. There are over 6700 species of amphibians and over 9000 species of reptiles, career options in the field of herpetology include, but are not limited to lab research, field studies and survey, zoological staff, museum staff and college teaching. In modern academic science, it is rare for individuals to consider themselves a herpetologist first and foremost, for example, an evolutionary biologist who is also a herpetologist may choose to work on an issue such as the evolution of warning coloration in coral snakes. Modern herpetological writers of note include Mark OShea and Philip Purser, most colleges or universities do not offer a major in herpetology at the undergraduate or even the graduate level. Instead, persons interested in herpetology select a major in the biological sciences, the knowledge learned about all aspects of the biology of animals is then applied to an individual study of herpetology. Herping List of herpetologists List of herpetology academic journals Adler, Kraig, contributions to the History of Herpetology. Society for the Study of Amphibians and Reptiles, bushmaster, Raymond Ditmars and the Hunt for the Worlds Largest Viper Goin, Coleman J. Olive B. Xi +378 pp. ISBN 0-7167-0020-4, herpMapper is a database of reptile and amphibian sightings
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Endemism
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The extreme opposite of endemism is cosmopolitan distribution. An alternative term for a species that is endemic is precinctive, the word endemic is from New Latin endēmicus, from Greek ενδήμος, endēmos, native. Endēmos is formed of en meaning in, and dēmos meaning the people, the term, precinctive, has been suggested by some scientists, and was first used in botany by MacCaughey in 1917. It is the equivalent of endemism, precinction was perhaps first used by Frank and McCoy. That definition excludes artificial confinement of examples by humans in far-off botanical gardens or zoological parks, physical, climatic, and biological factors can contribute to endemism. The orange-breasted sunbird is found in the fynbos vegetation zone of southwestern South Africa. The glacier bear is found only in limited places in Southeast Alaska, political factors can play a part if a species is protected, or actively hunted, in one jurisdiction but not another. There are two subcategories of endemism, paleoendemism and neoendemism, paleoendemism refers to species that were formerly widespread but are now restricted to a smaller area. Neoendemism refers to species that have arisen, such as through divergence and reproductive isolation or through hybridization. Endemics can easily become endangered or extinct if their restricted habitat changes, particularly—but not only—due to human actions, there were millions of both Bermuda petrels and Bermuda cedars in Bermuda when it was settled at the start of the seventeenth century. By the end of the century, the petrels were thought extinct, cedars, already ravaged by centuries of shipbuilding, were driven nearly to extinction in the twentieth century by the introduction of a parasite. Bermuda petrels and cedars are now rare, as are species endemic to Bermuda
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Atelopus varius
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Atelopus varius, also known as the clown frog, is a neo-tropical true toad from the family Bufonidae. A. zeteki has been considered a subspecies of A. varius, the historic range of A. varius stretched from the Pacific and Atlantic slopes of the Cordilleras de Tilaran mountain range in Costa Rica into western Panama. Suitable habitat includes both pre-montane and lower-montane zones as well as some lowland sites along streams in hilly areas. A. varius is a diurnal frog found on rocks or in crevices along streams in humid lowland. It is primarily a species, only entering the water during breeding season. The Costa Rican variable harlequin frog is slow moving and often remains in the area for long periods of time. The conspicuous or aposematic coloration of A. varius likely serves as a warning to predators of the toxicity of the frogs integument which contains tetrodotoxin. Its main food source is small arthropods that are most abundant during the dry season, the only known predator of A. varius is a parasitic sarcophagid fly which deposits its larvae on the surface of the frogs thigh. The larvae then proceed to burrow inside the frog and eat it from within, in recent decades, A. varius has become increasingly rare throughout its geographic range. By 1996, A. varius was believed to be extinct throughout Costa Rica, however, subsequent surveys carried out by the rainmaker project in 2003 and 2005 rediscovered a population of the endangered frog on the Pacific coastal range near Quepos. In Panama, mass mortality has drastically reduced populations of A. varius in recent years, several theories related to changes in climatic patterns have been put forth to account for the rapid decline of A. varius. A trend toward rising temperatures across the tropics in the late 1980s and early 1990s has been implicated in the declines of multiple lizard, more recently, an observed global decline in amphibian species richness has been linked to an outbreak of the pathogenic chytrid fungus Batrachochytrium dendrobatidis. Current attempts to preserve A. varius include a recently initiated captive breeding program as well as continued efforts to protect vital forest habitat, homing and site fidelity in a Neotropical frog, Atelopus varius. Aggression in harlequin frogs, male-male competition and a conflict of interest between the sexes. Lethal Parasitism of an Aposematic Anuran by Notochaeta bufonivora, mass mortality and population declines of anurans at an upland site in western Panama. Green, D. E. and Papendick, R.2003, chytridiomycosis in wild frogs from southern Costa Rica. Bustamante, M. R. Coloma, L. A. Consuegra, merino-Viteri, A. Puschendorf, R. Ron, S. R. Widespread amphibian extinctions from epidemic disease driven by global warming, harlequin Frogs Along a Tropical Montane Stream, Aggregation and the Risk of Predation by Frog-Eating Flies
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Habitat
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A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant, or other type of organism. The term typically refers to the zone in which the organism lives and it is the natural environment in which an organism lives, or the physical environment that surrounds a species population. Every organism has certain habitat needs for the conditions in which it will thrive, habitat types include polar, temperate, subtropical and tropical. The terrestrial vegetation type may be forest, steppe, grassland, the word habitat has been in use since about 1755 and derives from the Latin third-person singular present indicative of habitāre, to inhabit, from habēre, to have or to hold. Habitat can be defined as the environment of an organism. It is similar in meaning to a biotope, an area of environmental conditions associated with a particular community of plants. Generally speaking, animal communities are reliant on specific types of plant communities, some plants and animals are generalists, and their habitat requirements are met in a wide range of locations. The small white butterfly for example is found on all the continents of the world apart from Antarctica and its larvae feed on a wide range of Brassicas and various other plant species, and it thrives in any open location with diverse plant associations. Disturbance is important in the creation of biodiverse habitats, in the absence of disturbance, a climax vegetation cover develops that prevents the establishment of other species. Lightning strikes and toppled trees in tropical forests allow species richness to be maintained as pioneering species move in to fill the gaps created. Similarly coastal habitats can become dominated by kelp until the seabed is disturbed by a storm, another cause of disturbance is when an area may be overwhelmed by an invasive introduced species which is not kept under control by natural enemies in its new habitat. Terrestrial habitat types include forests, grasslands, wetlands and deserts, within these broad biomes are more specific habitats with varying climate types, temperature regimes, soils, altitudes and vegetation types. Many of these habitats grade into each other and each one has its own communities of plants. A habitat may suit a particular species well, but its presence or absence at any particular location depends to some extent on chance, on its dispersal abilities, freshwater habitats include rivers, streams, lakes, ponds, marshes and bogs. Although some organisms are found across most of these habitats, the majority have more specific requirements, similarly, aquatic plants can be floating, semi-submerged, submerged or grow in permanently or temporarily saturated soils besides bodies of water. Marine habitats include brackish water, estuaries, bays, the sea, the intertidal zone. Further variations include rock pools, sand banks, mudflats, brackish lagoons, sandy and pebbly beaches, the benthic zone or seabed provides a home for both static organisms, anchored to the substrate, and for a large range of organisms crawling on or burrowing into the surface. A desert is not the kind of habitat that favours the presence of amphibians, with their requirement for water to keep their skins moist, nevertheless, some frogs live in deserts, creating moist habitats underground and hibernating while conditions are adverse
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Habitat fragmentation
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Habitat fragmentation describes the emergence of discontinuities in an organisms preferred environment, causing population fragmentation and ecosystem decay. Not only causes loss of the amount of habitat, but by creating small, habitat fragmentation is the landscape level of the phenomenon, and patch level process. Thus meaning, it covers, the areas, edge effects. Evidence of habitat destruction through natural processes such as volcanism, fire, habitats which were once continuous become divided into separate fragments. After intensive clearing, the separate fragments tend to be small islands isolated from each other by cropland, pasture, pavement. The latter is often the result of slash and burn farming in tropical forests, one of the major ways that habitat fragmentation affects biodiversity is by reducing the amount of suitable habitat available for organisms. Habitat fragmentation often involves both habitat destruction and the subdivision of previously continuous habitat, plants and other sessile organisms are disproportionately affected by some types of habitat fragmentation because they cannot respond quickly to the altered spatial configuration of the habitat. As the remaining patches are smaller, they tend to support smaller populations of species. Small populations are at a risk of a variety of genetic consequences that influence their long-term survival. Remnant populations often contain only a subset of the diversity found in the previously continuous habitat. Processes that act upon underlying genetic diversity such as adaptation have a pool of fitness-maintaining alleles to survive in the face of environmental change. Populations can maintain genetic diversity through migration, in continuous habitats, migrants have few barriers to establish themselves in suitable sites. The percentage preservation of habitats is closely related to both genetic and species biodiversity preservation. Generally a 10% remnant contiguous habitat will result in a 50% biodiversity loss, minor fluctuations in climate, resources, or other factors that would be unremarkable and quickly corrected in large populations can be catastrophic in small, isolated populations. Thus fragmentation of habitat is an important cause of species extinction, population dynamics of subdivided populations tend to vary asynchronously. In an unfragmented landscape a declining population can be rescued by immigration from an expanding population. In fragmented landscapes, the distance between fragments may prevent this from happening, additionally, unoccupied fragments of habitat that are separated from a source of immigrants by some barrier are less likely to be repopulated than adjoining fragments. Even small species such as the Columbia spotted frog are reliant on the rescue effect, studies showed 25% of juveniles travel a distance over 200m compared to 4% of adults
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Genetic drift
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Genetic drift is the change in the frequency of a gene variant in a population due to random sampling of organisms. The alleles in the offspring are a sample of those in the parents, a populations allele frequency is the fraction of the copies of one gene that share a particular form. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation, when there are few copies of an allele, the effect of genetic drift is larger, and when there are many copies the effect is smaller. In the early 20th century, vigorous debates occurred over the importance of natural selection versus neutral processes. The process of genetic drift can be illustrated using 20 marbles in a jar to represent 20 organisms in a population, consider this jar of marbles as the starting population. Half of the marbles in the jar are red and half blue, in each new generation the organisms reproduce at random. To represent this reproduction, randomly select a marble from the original jar, repeat this process until there are 20 new marbles in the second jar. The second jar then contains a second generation of offspring, consisting of 20 marbles of various colours, unless the second jar contains exactly 10 red marbles and 10 blue marbles, a random shift occurred in the allele frequencies. Repeat this process a number of times, randomly reproducing each generation of marbles to form the next, the numbers of red and blue marbles picked each generation fluctuates, sometimes more red and sometimes more blue. This fluctuation is analogous to genetic drift – a change in the allele frequency resulting from a random variation in the distribution of alleles from one generation to the next. It is even possible that in any one generation no marbles of a particular colour are chosen, in this example, if no red marbles are selected, the jar representing the new generation contains only blue offspring. If this happens, the red allele has been lost permanently in the population, while the remaining blue allele has become fixed, in small populations, fixation can occur in just a few generations. The mechanisms of genetic drift can be illustrated with a simplified example, consider a very large colony of bacteria isolated in a drop of solution. The bacteria are genetically identical except for a gene with two alleles labeled A and B. A and B are neutral alleles meaning that they do not affect the ability to survive and reproduce, all bacteria in this colony are equally likely to survive. Suppose that half the bacteria have allele A and the other half have allele B, thus A and B each have allele frequency 1/2. The drop of solution then shrinks until it has enough food to sustain four bacteria. All other bacteria die without reproducing, among the four who survive, there are sixteen possible combinations for the A and B alleles
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Pollutant
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A pollutant is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. A pollutant may cause long- or short-term damage by changing the rate of plant or animal species, or by interfering with human amenities, comfort, health. Some pollutants are biodegradable and therefore will not persist in the environment in the long term, however the degradation products of some pollutants are themselves polluting such as the products DDE and DDD produced from degradation of DDT. Pollutants, towards which the environment has little or no absorptive capacity are called stock pollutants, stock pollutants accumulate in the environment over time. The damage they cause increases as more pollutant is emitted, stock pollutants can create a burden for future generations, by passing on damage that persists well after the ‘benefits received from incurring that damage, have been forgotten. Fund pollutants are those for which the environment has some absorptive capacity, fund pollutants do not cause damage to the environment unless the emission rate exceeds the receiving environments absorptive capacity. Fund pollutants are not destroyed, but rather converted into less harmful substances and it also encompasses ecological light pollution which describes the effect of artificial light on individual organisms and on the structure of ecosystems as a whole. Pollutants can also be defined by their zones of influence, both horizontally and vertically, the horizontal zone refers to the area that is damaged by a pollutant. Local pollutants cause damage near the emission source, regional pollutants cause damage further from the emission source. The vertical zone is referred to whether the damage is ground-level or atmospheric, surface pollutants cause damage by concentrations of the pollutant accumulating near the Earths surface Global pollutants cause damage by concentrations in the atmosphere. Pollutants can cross borders and therefore international regulations are needed for their control. The Stockholm Convention on Persistent Organic Pollutants, which entered force in 2004, is an international legally binding agreement for the control of persistent organic pollutants. Pollutant Release and Transfer Registers are systems to collect and disseminate information on releases and transfers of toxic chemicals from industrial. The National Emissions Standards for Hazardous Air Pollutants are additional emission standards that are set by EPA for toxic air pollutants, under the Clean Water Act, EPA promulgated national standards for municipal sewage treatment plants, also called publicly owned treatment works, in the Secondary Treatment Regulation. National standards for industrial dischargers are called Effluent guidelines and New Source Performance Standards, in addition, the Act requires states to publish water quality standards for individual water bodies to provide additional protection where the national standards are insufficient. The Resource Conservation and Recovery Act regulates the management, transport and disposal of solid waste, hazardous waste. A tank or piping network that has at least 10 percent of its volume underground is known as a storage tank. They often store substances such as petroleum, that are harmful to the environment should it become contaminated
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Atrazine
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Atrazine is an herbicide of the triazine class. Atrazine is used to prevent pre- and postemergence broadleaf weeds in crops such as maize and sugarcane and on turf, such as golf courses and it is one of the most widely used herbicides in US and Australian agriculture. As of 2001, atrazine was the most commonly detected pesticide contaminating drinking water in the United States, studies suggest it is an endocrine disruptor, an agent that can alter the natural hormonal system. EPA started a review in 2013. The EPAs review has been criticized, and the safety of atrazine remains controversial, in the United States as of 2014, atrazine was the second-most widely used herbicide after glyphosate, with 76 million pounds of it applied each year. Atrazine continues to be one of the most widely used herbicides in Australian agriculture and its effect on corn yields has been estimated from 1% to 8%, with 3–4% being the conclusion of one economics review. Effects on sorghum yields have been estimated to be as high as 20%, Atrazine was invented in 1958 in the Geigy laboratories as the second of a series of 1,3, 5-triazines. Atrazine is prepared from cyanuric chloride, which is treated sequentially with ethylamine, like other triazine herbicides, atrazine functions by binding to the plastoquinone-binding protein in photosystem II, which animals lack. Plant death results from starvation and oxidative damage caused by breakdown in the transport process. Oxidative damage is accelerated at high light intensity, atrazines effects in humans and animals primarily involve the endocrine system. Studies suggest that atrazine is an endocrine disruptor that can cause hormone imbalance, Atrazine has been found to act as an agonist of the G protein-coupled estrogen receptor 1. Atrazine was banned in the European Union in 2004 because of its persistent groundwater contamination, Atrazine contamination of surface water has been monitored by the EPA and has consistently exceeded levels of concern in two Missouri watersheds and one in Nebraska. As of 2001, Atrazine was the most commonly detected pesticide in US drinking water, surface water monitoring data from 20 high atrazine use watersheds found peak atrazine levels up to 147 parts per billion, with daily averages in all cases below 10 parts per billion. Atrazine remains in soil for a matter of months and can migrate from soil to groundwater, once in groundwater and it has been detected in groundwater at high levels in some regions of the U. S. where it is used on some crops and turf. The US Environmental Protection Agency expresses concern regarding contamination of surface waters, Atrazine degrades in soil primarily by the action of microbes. The half-life of atrazine in soil ranges from 13 to 261 days, Atrazine biodegradation can occur by two known pathways, Hydrolysis of the C-Cl bond is followed by the ethyl and isopropyl groups, catalyzed by the hydrolase enzymes called AtzA, AtzB, and AtzC. The end product of this process is cyanuric acid, itself unstable with respect to ammonia, the best characterized organisms that use this pathway are of Pseudomonas sp. strain ADP. Dealkylation of the amino groups gives 2-chloro-4-hydroxy-6-amino-1,3, 5-triazine and this path also occurs in Pseudomonas species, as well as a number of bacteria
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Glyphosate
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Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is a compound, specifically a phosphonate. It is used to kill weeds, especially annual broadleaf weeds and it was discovered to be an herbicide by Monsanto chemist John E. Franz in 1970. Monsanto brought it to market in 1974 under the trade name Roundup, farmers quickly adopted glyphosate, especially after Monsanto introduced glyphosate-resistant Roundup Ready crops, enabling farmers to kill weeds without killing their crops. In 2007, glyphosate was the most used herbicide in the United States agricultural sector and the second-most used in home and garden, government and industry, glyphosate is absorbed through foliage, and minimally through roots, and transported to growing points. It inhibits a plant enzyme involved in the synthesis of three amino acids, tyrosine, tryptophan, and phenylalanine. Therefore, it is only on actively growing plants and is not effective as a pre-emergence herbicide. An increasing number of crops have been engineered to be tolerant of glyphosate which allows farmers to use glyphosate as a postemergence herbicide against weeds. The development of resistance in weed species is emerging as a costly problem. While glyphosate and formulations such as Roundup have been approved by regulatory bodies worldwide, concerns about their effects on humans, many regulatory and scholarly reviews have evaluated the relative toxicity of glyphosate as an herbicide. A meta-analysis published in 2014 identified an increased risk of NHL in workers exposed to glyphosate formulations, glyphosate was first synthesized in 1950 by Swiss chemist Henry Martin, who worked for the Swiss company Cilag. Stauffer Chemical patented the agent as a chemical chelator in 1964 as it binds and removes minerals such as calcium, magnesium, manganese, copper, somewhat later, glyphosate was independently discovered at Monsanto in 1970. Monsanto chemists had synthesized about 100 derivatives of aminomethylphosphonic acid as potential water-softening agents, two were found to have weak herbicidal activity, and John E. Franz, a chemist at Monsanto, was asked to try to make analogs with stronger herbicidal activity. Glyphosate was the third analog he made, Franz received the National Medal of Technology in 1987 and the Perkin Medal for Applied Chemistry in 1990 for his discoveries. In 2008, USDA-ARS scientist Stephen O. Duke and Stephen B, Powles, an Australian weed expert — described glyphosate as a virtually ideal herbicide. In 2010 Powles stated, glyphosate is a one in a 100-year discovery that is as important for reliable global food production as penicillin is for battling disease. Glyphosate is an analogue of the natural amino acid glycine. Both the phosphonic acid and carboxylic acid moieties can be ionised and the group can be protonated
44.
Malathion
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Malathion is an organophosphate insecticide of relatively low human toxicity. In the former USSR, it was known as carbophos, in New Zealand and Australia as maldison, malathion is a pesticide that is widely used in agriculture, residential landscaping, public recreation areas, and in public health pest control programs such as mosquito eradication. In the US, it is the most commonly used organophosphate insecticide, malathion as a mixture with corn syrup was used in the 1980s in Australia and California to combat the Mediterranean fruit fly. In Canada and the US, malathion was sprayed in many cities to combat west Nile virus, malathion was used over the last couple of decades on a regular basis during summer months to kill mosquitoes, but homeowners were allowed to exempt their properties if they chose. Today, Winnipeg is the major city in Canada with an ongoing malathion adult-mosquito-control program. Malathion is an inhibitor, a diverse family of chemicals that includes sarin. Upon uptake into the organism, it binds irreversibly to several, random serine residues on the cholinesterase enzyme. The resultant phosphoester group is bound to the cholinesterase. It is produced by the addition of dimethyl dithiophosphoric acid to diethyl maleate, the compound is chiral but is used as a racemate. Malathion in low doses is used as a treatment for, Head lice, malathion is approved by the US Food and Drug Administration for treatment of pediculosis. It is claimed to kill both the eggs and the adult lice, but in fact has been shown in UK studies to be only 36% effective on head lice. Scabies Preparations include Derbac-M, Prioderm, Quellada-M and Ovide, malathion is of low toxicity, however, absorption or ingestion into the human body readily results in its metabolism to malaoxon, which is substantially more toxic. In studies of the effects of exposure to oral ingestion of malaoxon in rats. It is cleared from the body quickly, in three to five days, according to the United States Environmental Protection Agency there is currently no reliable information on adverse health effects of chronic exposure to malathion. Acute exposure to high levels of malathion will cause body-wide symptoms whose intensity will be dependent on the severity of exposure. Symptoms include skin and eye irritation, cramps, nausea, diarrhea, excessive sweating, seizures, most symptoms tend to resolve within several weeks. In 1981, B. T. Collins, director of the California Conservation Corps, publicly swallowed a mouthful of dilute malathion solution and this was an attempt to demonstrate malathions safety following an outbreak of Mediterranean fruit flies in California. Malathion was sprayed over a 1,400 sq mi area to control the flies, in 1976, numerous malaria workers in Pakistan were poisoned by isomalathion, a contaminant that may be present in some preparations of malathion
45.
Carbaryl
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Carbaryl is a chemical in the carbamate family used chiefly as an insecticide. It is a crystalline solid commonly sold under the brand name Sevin. Union Carbide discovered carbaryl and introduced it commercially in 1958, Bayer purchased Aventis CropScience in 2002, a company that included Union Carbide pesticide operations. It remains the third-most-used insecticide in the United States for home gardens, commercial agriculture, about 11 million kilograms were applied to U. S. farm crops in 1976. As a veterinary drug, it is known as carbaril, carbaryl is produced by treating methyl isocyanate with 1-naphthol. Alternatively, 1-naphthol is reacted with phosgene to synthesize its chloroformate, in comparison, the latter synthesis uses exactly the same reagents, but in a different sequence. This synthesis avoids the preparation of methyl isocyanate, and the comparison is used as a case study in green chemistry. However, the second synthesis still uses phosgene, which is toxic and reacts with water, and methylamine, carbamate insecticides are slowly reversible inhibitors of the enzyme acetylcholinesterase. They resemble acetylcholine, but the enzyme undergoes the final hydrolysis step very slowly compared with the acetylated enzyme generated by acetylcholine. They interfere with the nervous system and cause death because the effects of the neurotransmitter acetylcholine cannot be terminated by carbamoylated acetylcholinesterase. The development of the carbamate insecticides has been called a breakthrough in pesticides. The carbamates do not have the persistence of chlorinated pesticides, although toxic to insects, carbaryl is detoxified and eliminated rapidly in vertebrates. It is neither concentrated in fat nor secreted in milk, so is favored for food crops and it is the active ingredient in Carylderm shampoo used to combat head lice until infestation is eliminated. Carbaryl kills both targeted and beneficial insects, as well as crustaceans, although approved for more than 100 crops in the US, carbaryl is illegal in several countries, including the United Kingdom, Austria, Denmark, Sweden, Iran, Germany, and Angola. Carbaryl is often produced using methyl isocyanate as an intermediary, a leak of MIC used in the production of carbaryl caused the Bhopal disaster, the largest industrial accident in history. Carbaryl is an inhibitor and is toxic to humans. It is classified as a human carcinogen by the United States Environmental Protection Agency The oral LD50 is 250 to 850 mg/kg for rats and 100 to 650 mg/kg for mice
46.
Polyethoxylated tallow amine
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Polyethoxylated tallow amine refers to a range of non-ionic surfactants derived from animal fats. They primarily find used as emulsifiers and wetting agents for agrochemical formulations, animal fat is hydroysed to give the free fatty acids. These are then converted to fatty amines via the process before being ethoxylated with ethylene oxide. The length of the fatty tail and degree of exothylation will determine the properties of the surfactant. Due to it being synthesized from an impure material POEA is itself a mixture compounds, the polyethoxylated tallow amine used as a surfactant is referred to in the literature as MON0139 or polyoxyethyleneamine. It is contained in the herbicide Roundup, an ethoxylated tallow amine, is on the U. S. EPA List 3 of Inert Ingredients of Pesticides. POEA concentrations range from <1% in ready-to-use glyphosate formulations to 21% in concentrates, POEA constitutes 15% of Roundup formulations and the phosphate ester neutralized polyethoxylated tallow amine surfactant constitutes 14. 5% of Roundup Pro. The chemical complexity of POEA makes it difficult to study in the environment, POEA is toxic to aquatic species like fish and amphibians. As other surfactants as well, it can affect membrane transport, in laboratory experiments POEA has a half-life in soils of less than 7 days. Washout from soil is assumed to be minimal, and the estimated half-life in bodies of water would be about 2 weeks. Glyphosate has an LD50 ranging from 4.2 times that of POEA for midge larvae at pH6.5, to 369 times that of POEA for rainbow trout at pH9.5. The pH value of most freshwater streams and lakes is between 6.0 and 9.0, fish species are harmed by water having a pH value outside of this range, two reviews have been published on the toxicity of POEA to humans. The earlier, published in 2000, evaluated studies that were performed for regulatory purposes as well as published research reports and it found that no significant toxicity occurred in acute, subchronic, and chronic studies. Direct ocular exposure to the concentrated Roundup formulation can result in transient irritation, while normal spray dilutions cause, at most, results from standard studies with these materials also failed to show any effects indicative of endocrine modulation. Therefore, it is concluded that the use of Roundup herbicide does not result in effects on development, reproduction, or endocrine systems in humans. It was concluded that, under present and expected conditions of use, there is insufficient evidence to conclude that glyphosate preparations containing POEA are more toxic than those containing alternative surfactants. Although surfactants probably contribute to the toxicity of glyphosate formulations. Ingestion of >85 mL of the formulation is likely to cause significant toxicity in adults
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. PMID 10620528.[dead link]
