Eighty percent of marine pollution comes from land. Air pollution is a factor by carrying off pesticides or dirt into the ocean. Land and air pollution have proven to be harmful to marine life, the pollution often comes from non point sources such as agricultural runoff, wind-blown debris and dust. Nutrient pollution, a form of pollution, refers to contamination by excessive inputs of nutrients. It is a cause of eutrophication of surface waters, in which excess nutrients, usually nitrogen or phosphorus. Many potentially toxic chemicals adhere to tiny particles which are taken up by plankton and benthos animals. In this way, the toxins are concentrated upward within ocean food chains, many particles combine chemically in a manner highly depletive of oxygen, causing estuaries to become anoxic. When pesticides are incorporated into the ecosystem, they quickly become absorbed into marine food webs. Once in the webs, these pesticides can cause mutations, as well as diseases. Toxic metals can be introduced into marine food webs and these can cause a change to tissue matter, behaviour and suppress growth in marine life.
Also, many animal feeds have a fish meal or fish hydrolysate content. In this way, marine toxins can be transferred to land animals, although marine pollution has a long history, significant international laws to counter it were only enacted in the twentieth century. Marine pollution was a concern during several United Nations Conferences on the Law of the Sea beginning in the 1950s, most scientists believed that the oceans were so vast that they had unlimited ability to dilute, and thus render pollution harmless. After the Mediterranean Sea controversy, for example, Jacques Cousteau became a figure in the campaign to stop marine pollution. Marine pollution made further international headlines after the 1967 crash of the oil tanker Torrey Canyon, Marine pollution was a major area of discussion during the 1972 United Nations Conference on the Human Environment, held in Stockholm. That year saw the signing of the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, the London Convention did not ban marine pollution, but it established black and gray lists for substances to be banned or regulated by national authorities.
Cyanide and high-level radioactive waste, for example, were put on the black list, the London Convention applied only to waste dumped from ships, and thus did nothing to regulate waste discharged as liquids from pipelines. There are many different ways to categorize, and examine the inputs of pollution into our marine ecosystems, one common path of entry by contaminants to the sea are rivers
The Progressive Era was a period of widespread social activism and political reform across the United States, from the 1890s to the 1920s. The main objectives of the Progressive movement were eliminating problems caused by industrialization, immigration, the movement primarily targeted political machines and their bosses. By taking down these corrupt representatives in office a further means of democracy would be established. They sought regulation of monopolies and corporations through antitrust laws and these antitrust laws were seen as a way to promote equal competition for the advantage of legitimate competitors. Many progressives supported prohibition in the United States, ostensibly to destroy the power of local bosses based in saloons. At the same time, womens suffrage was promoted to bring a purer female vote into the arena, many activists joined efforts to reform local government, public education, finance, industry, railroads and many other areas. Progressives transformed and made scientific the social sciences, especially history, economics, in academic fields the day of the amateur author gave way to the research professor who published in the new scholarly journals and presses.
The national political leaders included Theodore Roosevelt, Robert M, La Follette, Sr. and Charles Evans Hughes on the Republican side, and William Jennings Bryan, Woodrow Wilson and Al Smith on the Democratic side. Yet, leaders of the movement existed far from presidential politics, jane Addams, Grace Abbott, Edith Abbott and Sophonisba Breckinridge were among the most influential Progressive Era reformers. Initially the movement operated chiefly at local levels, later, it expanded to state, Progressives drew support from the middle class, and supporters included many lawyers, physicians and business people. Some Progressives strongly supported scientific methods as applied to economics, industry, medicine, theology, reformers felt that old-fashioned ways meant waste and inefficiency, and eagerly sought out the one best system. S. Magazines were not a new medium but they became more popular around 1900. It was an age of Mass media, thanks to the rapid expansion of national advertising, the cover price fell sharply to about 10 cents.
One cause was the coverage of corruption in politics, local government and big business. They were journalists who wrote for magazines to expose social and political sins. They relied on their own investigative journalism reporting, muckrakers often worked to expose social ills and corporate, the journalists who specialized in exposing waste and scandal operated at the state and local level, like Ray Stannard Baker, George Creel, and Brand Whitlock. Other like Lincoln Steffens exposed political corruption in many large cities, Roosevelt gave these journalists their nickname when he complained they were not being helpful by raking up all the muck. The Progressives were avid modernizers, with a belief in science and they looked to education as the key
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the cause of the greenhouse effect. The primary greenhouse gases in Earths atmosphere are water vapor, carbon dioxide, nitrous oxide, without greenhouse gases, the average temperature of Earths surface would be about −18 °C, rather than the present average of 15 °C. In the Solar System, the atmospheres of Venus, human activities since the beginning of the Industrial Revolution have produced a 40% increase in the atmospheric concentration of carbon dioxide, from 280 ppm in 1750 to 400 ppm in 2015. This increase has occurred despite the uptake of a portion of the emissions by various natural sinks involved in the carbon cycle. Anthropogenic carbon dioxide emissions come from combustion of fuels, principally coal, oil. Greenhouse gases are those that absorb and emit infrared radiation in the range emitted by Earth. The proportion of an emission remaining in the atmosphere after a time is the airborne fraction.
The annual airborne fraction is the ratio of the increase in a given year to that years total emissions. Over the last 50 years the annual airborne fraction for CO2 has been increasing at 0.25 ±0. 21%/year, they do not contribute significantly to the greenhouse effect and usually are omitted when discussing greenhouse gases. Some gases have indirect radiative effects and this happens in two main ways. One way is that when they break down in the atmosphere they produce another greenhouse gas, for example and carbon monoxide are oxidized to give carbon dioxide. Oxidation of CO to CO2 directly produces an increase in radiative forcing although the reason is subtle. The peak of the thermal IR emission from Earths surface is close to a strong vibrational absorption band of CO2. On the other hand, the single CO vibrational band only absorbs IR at much higher frequencies, where the ~300 K thermal emission of the surface is at least a factor of ten lower. Oxidation of methane to CO2, which requires reactions with the OH radical, produces a reduction, since CO2 is a weaker greenhouse gas than methane.
As described below this is not the story, since the oxidations of CO. In any case, the calculation of the radiative effect needs to include both the direct and indirect forcing
Conservation in the United States
Conservation in the United States can be traced back to the 19th century with the formation of the first National Park. Conservation generally refers to the act of consciously and efficiently using land and/or its natural resources. This can be in the form of setting aside tracts of land for protection from hunting or urban development, or it can take the form of using resources such as metal, water. Usually, this process of conservation occurs through or after legislation on local or national levels is passed, during the 19th century, some Americans developed a deep and abiding passion for nature. Likewise, in 1860, Frederic Edwin Church painted Twilight in the Wilderness, many American writers romanticized and focused upon nature as a subject matter. However, the most notable literary figure upon the early conservation movement proved to be Henry David Thoreau, throughout his work, Thoreau detailed his experiences at the natural setting of Walden Pond and his deep appreciation for nature.
In one instance, he described a deep grief for a tree that was cut down, as he states in Walden, Thoreau was interested in the preservation of nature. This speech became one of Thoreaus most influential contributions to conservationist thought. The early conservation movement in the United States was due to the hard work of John Muir. Muir, who is cited as one of the first American environmentalists, has earned multiple American honors for environmental work. His family home in Martinez, California, is honored as a National Historic Site and so is his home in Portage. He was a former worker who was nearly blinded by an accident at work. After almost losing his sight, Muir decided to see Americas natural wonders, based upon his travels throughout Yosemite and the Sierra Nevada Mountains, Muir wrote a collection of articles for Century magazine, entitled Studies in the Sierra. Early Americans recognized the importance of resources and the necessity of wilderness preservation for sustained yield harvesting of natural resources.
In essence, the preservation of wilderness and landscapes were recognized as critical for future generations, the foundation of the conservation movement is grounded during this period between 1850 and 1920. Ultimately, historical trends and cultural mind-sets were united, which influenced ideas, environmental historians, like Carolyn Merchant, cite Muir as someone who was unwilling to extend his efforts of conservation toward groups of people who were not white. America had its own movement in the 19th century, most often characterized by George Perkins Marsh, author of Man. The expedition into northwest Wyoming in 1871 led by F. V, travels by U. S. President Theodore Roosevelt through the region around Yellowstone provided the impetus for the creation of the Yellowstone Timberland Reserve in 1891
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, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, mollusks, mammals, nematodes, although pesticides have benefits, some 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, 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, nicotinoids, and a fourth group that includes strychnine and scilliroside. Many pesticides can be grouped into chemical families, prominent insecticide families include organochlorines 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 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
Global warming and climate change are terms for the observed century-scale rise in the average temperature of the Earths climate system and its related effects. Multiple lines of evidence show that the climate system is warming. The largest human influence has been emission of gases such as carbon dioxide, methane. These findings have been recognized by the science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing. Future climate change and associated impacts will differ from region to region around the globe, anticipated effects include warming global temperature, rising sea levels, changing precipitation, and expansion of deserts in the subtropics. Warming is expected to be greater over land than over the oceans and greatest in the Arctic, with the retreat of glaciers, permafrost. Effects significant to humans include the threat to security from decreasing crop yields. Possible societal responses to global warming include mitigation by emissions reduction, adaptation to its effects, building systems resilient to its effects, most countries are parties to the United Nations Framework Convention on Climate Change, whose ultimate objective is to prevent dangerous anthropogenic climate change.
Public reactions to global warming and concern about its effects are increasing, a global 2015 Pew Research Center report showed a median of 54% consider it a very serious problem. There are significant regional differences, with Americans and Chinese among the least concerned, the global average surface temperature shows a warming of 0.85 °C in the period 1880 to 2012, based on multiple independently produced datasets. Earths average surface temperature rose by 0. 74±0.18 °C over the period 1906–2005, the rate of warming almost doubled for the last half of that period. The rest has melted ice and warmed the continents and atmosphere, the average temperature of the lower troposphere has increased between 0.12 and 0.135 °C per decade since 1979, according to satellite temperature measurements. The warming that is evident in the temperature record is consistent with a wide range of observations. The probability that these changes could have occurred by chance is virtually zero, temperature changes vary over the globe.
Since 1979, land temperatures have increased about twice as fast as ocean temperatures, ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation. Since the beginning of industrialisation the temperature difference between the hemispheres has increased due to melting of sea ice and snow in the North. Average arctic temperatures have been increasing at almost twice the rate of the rest of the world in the past 100 years, the thermal inertia of the oceans and slow responses of other indirect effects mean that climate can take centuries or longer to adjust to changes in forcing. Some of this warming will be driven by past natural forcings which are still seeking equilibrium in the climate system
While environmentalism focuses more on the environmental and nature-related aspects of green ideology and politics, ecologism combines the ideology of social ecology and environmentalism. ‘Ecologism’ is more used in continental European languages while ‘environmentalism’ is more commonly used in English. For this reason, concepts such as an ethic, environmental ethics, ecology. The exact measures and outcomes of this balance is controversial and there are different ways for environmental concerns to be expressed in practice. Environmentalism and environmental concerns are represented by the color green. Environmentalism denotes a movement that seeks to influence the political process by lobbying, activism. The word was first coined in 1922, an environmentalist is a person who may speak out about our natural environment and the sustainable management of its resources through changes in public policy or individual behavior. In various ways, environmentalists and environmental organizations seek to give the world a stronger voice in human affairs.
In general terms, environmentalists advocate the sustainable management of resources, in its recognition of humanity as a participant in ecosystems, the movement is centered around ecology and human rights. A concern for environmental protection has recurred in diverse forms, in different parts of the world, for example, in Europe, King Edward I of England banned the burning of sea-coal by proclamation in London in 1272, after its smoke had become a problem. 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. Earlier in the Middle East, the Caliph Abu Bakr in the 630s commanded his army to Bring no harm to the trees, nor burn them with fire, at the advent of steam and electricity the muse of history holds her nose and shuts her eyes. The origins of the movement lay in the response to increasing levels of smoke pollution in the atmosphere during the Industrial Revolution. An Alkali inspector and four sub-inspectors were appointed to curb this pollution, typically the highest priority went to water and air pollution.
The Coal Smoke Abatement Society was formed in 1898 making it one of the oldest environmental NGOs and it was founded by artist Sir William Blake Richmond, frustrated with the pall cast by coal smoke. Although there were pieces of legislation, the Public Health Act 1875 required all furnaces and fireplaces to consume their own smoke. It provided for sanctions against factories that emitted large amounts of black smoke, financial incentives were offered to householders to replace open coal fires with alternatives, or for those who preferred, to burn coke instead which produces minimal smoke. Smoke control areas were introduced in some towns and cities in which only smokeless fuels could be burnt, the act formed an important impetus to modern environmentalism, and caused a rethinking of the dangers of environmental degradation to peoples quality of life
His letters and books describing his adventures in nature, especially in the Sierra Nevada, have been read by millions. His activism has helped to preserve the Yosemite Valley, Sequoia National Park, the Sierra Club, which he founded, is a prominent American conservation organization. The 211-mile John Muir Trail, a trail in the Sierra Nevada, was named in his honor. Other such places include Muir Woods National Monument, Muir Beach, John Muir College, Mount Muir, in Scotland, the John Muir Way, a 130-mile-long route, was named in honor of him. In his life, Muir devoted most of his time to the preservation of the Western forests and he petitioned the U. S. Congress for the National Park bill that was passed in 1890, establishing Yosemite National Park. The spiritual quality and enthusiasm toward nature expressed in his writings has inspired readers, including presidents and congressmen, today Muir is referred to as the Father of the National Parks and the National Park Service has produced a short documentary about his life.
John Muir has been considered an inspiration to both Scots and Americans, Muirs biographer, Steven J. Holmes, believes that Muir has become one of the patron saints of twentieth-century American environmental activity, both political and recreational. As a result, his writings are discussed in books and journals. Muir has profoundly shaped the very categories through which Americans understand and envision their relationships with the natural world, on April 21,2013, the first ever John Muir Day was celebrated in Scotland, which marked the 175th anniversary of his birth, paying homage to the conservationist. John Muirs Birthplace is a stone house in Dunbar, East Lothian. His parents were Daniel Muir and Ann Gilrye and he was the third of eight children, Sarah, Daniel and Mary, and the American-born Joanna. His earliest recollections were of taking short walks with his grandfather when he was three, author Amy Marquis notes that he began his love affair with nature while young, and implies that it may have been in reaction to his strict religious upbringing.
His father believed that anything that distracted from Bible studies was frivolous, but the young Muir was a restless spirit and especially prone to lashings. As a young boy, Muir became fascinated with the East Lothian landscape and it was during this time that he became interested in natural history and the works of Scottish naturalist Alexander Wilson. Although he spent the majority of his life in America, Muir never forgot his roots in Scotland and he held a strong connection with his birthplace and Scottish identity throughout his life and was frequently heard talking about his childhood spent amid the East Lothian countryside. He greatly admired the works of Thomas Carlyle and poetry of Robert Burns and he returned to Scotland on a trip in 1893, where he met one of his Dunbar schoolmates and visited the places of his youth that were etched in his memory. He never lost his strong Scottish accent after many years living in America, in 1849, Muirs family immigrated to the United States, starting a farm near Portage, called Fountain Lake Farm.
It has been designated a National Historic Landmark, by age 11, young Muir had learned to recite by heart and by sore flesh all of the New Testament and most of the Old Testament
Nuclear power in the United States
As of 2016, there are four new reactors under construction with a gross electrical capacity of 5,000 MW, while 33 reactors have been permanently shut down. The United States is the worlds largest supplier of nuclear power. As of October 2014, the NRC has granted license renewals providing a 20-year extension to a total of 74 reactors. In early 2014, the NRC prepared to receive the first applications of license renewal beyond 60 years of life, as early as 2017. Licenses for 22 reactors are due to expire before the end of the next decade if no renewals are granted, the Vermont Yankee Nuclear Power Plant was the most recent nuclear power plant to be decommissioned on December 29,2014. Most reactors began construction by 1974, following the Three Mile Island accident in 1979 and changing economics, more than 100 orders for nuclear power reactors, many already under construction, were canceled in the 1970s and 1980s, bankrupting some companies. Up until 2013, there had been no ground-breaking on new reactors at existing power plants since 1977.
Then in 2012, the NRC approved construction of four new reactors at existing nuclear plants, Summer Nuclear Generating Station Units 2 and 3 began on March 9,2013. A few days later, on March 12, construction began on the Vogtle Electric Generating Plant Units 3 and 4, in addition, on October 19,2016 TVAs Unit-2 reactor at the Watts Bar Nuclear Generating Station became the first US reactor to enter commercial operation since 1996. There was a revival of interest in power in the 2000s, with talk of a nuclear renaissance. As of August 2013, there are construction delays at Vogtle, Research into the peaceful uses of nuclear materials began in the United States under the auspices of the Atomic Energy Commission, created by the United States Atomic Energy Act of 1946. This led to the introduction of the Price-Anderson Act in 1957, the Price-Anderson Act. shields nuclear utilities and suppliers against liability claims in the event of a catastrophic accident by imposing an upper limit on private sector liability.
Without such protection, private companies were unwilling to become involved, no other technology in the history of American industry has enjoyed such continuing blanket protection. Argonne National Laboratory was assigned by the United States Atomic Energy Commission the lead role in developing nuclear energy beginning in the 1940s. Argonne and a number of other AEC contractors built a total of 52 reactors at the National Reactor Testing Station, two were never operated, except for the Neutron Radiography Facility, all the other reactors were shut down by 2000. Electricity from a generator connected to Experimental Breeder Reactor I flowed through them and this was the first time that a usable amount of electrical power had ever been generated from nuclear fission. Only days afterward, the reactor produced all the electricity needed for the entire EBR complex, one ton of natural uranium can produce more than 40 million kilowatt-hours of electricity — this is equivalent to burning 16,000 tons of coal or 80,000 barrels of oil.
More central to EBR-I’s purpose than just generating electricity, was its role in proving that a reactor could create more nuclear fuel as a byproduct than it consumed during operation, in 1953, tests verified that this was the case
Yosemite National Park
Yosemite National Park is a national park spanning portions of Tuolumne and Madera counties in Northern California. The park, which is managed by the National Park Service, on average, about 4 million people visit Yosemite each year, and most spend the majority of their time in the seven square miles of Yosemite Valley. The park set a record in 2016, surpassing 5 million visitors for the first time in its history. Almost 95% of the park is designated wilderness, Yosemite was central to the development of the national park idea. First, Galen Clark and others lobbied to protect Yosemite Valley from development, Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and the park supports a diversity of plants and animals. The park has a range from 2,127 to 13,114 feet and contains five major vegetation zones, chaparral/oak woodland, lower montane forest, upper montane forest, subalpine zone. Of Californias 7,000 plant species, about 50% occur in the Sierra Nevada, there is suitable habitat for more than 160 rare plants in the park, with rare local geologic formations and unique soils characterizing the restricted ranges many of these plants occupy.
The geology of the Yosemite area is characterized by granitic rocks, about 10 million years ago, the Sierra Nevada was uplifted and tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, about one million years ago and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet during the early glacial episode, the downslope movement of the ice masses cut and sculpted the U-shaped valley that attracts so many visitors to its scenic vistas today. The name Yosemite originally referred to the name of a tribe which was driven out of the area by the Mariposa Battalion. Before the area was called Ahwahnee by indigenous people, as revealed by archeological finds, the Yosemite Valley has been inhabited for nearly 3,000 years, though humans may have first visited the area as long as 8,000 to 10,000 years ago.
The indigenous natives called themselves the Ahwahneechee, meaning dwellers in Ahwahnee and they are related to the Northern Paiute and Mono tribes. Many tribes visited the area to trade, including nearby Central Sierra Miwoks, a major trading route went over Mono Pass and through Bloody Canyon to Mono Lake, just to the east of the Yosemite area. Vegetation and game in the region were similar to that present today, acorns were a staple to their diet, as well as seeds and plants, salmon. In 1851 as part of the Mariposa Wars intended to suppress Native American resistance and he was pursuing forces of around 200 Ahwahneechee led by Chief Tenaya. Accounts from this battalion were the first well-documented reports of ethnic Europeans entering Yosemite Valley, attached to Savages unit was Dr. Lafayette Bunnell, the company physician, who wrote about his awestruck impressions of the valley in The Discovery of the Yosemite. Bunnell is credited with naming Yosemite Valley, based on his interviews with Chief Tenaya, Bunnell wrote that Chief Tenaya was the founder of the Pai-Ute Colony of Ah-wah-nee
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 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
The bald eagle is a bird of prey found in North America. A sea eagle, it has two subspecies and forms a species pair with the white-tailed eagle. Its range includes most of Canada and Alaska, all of the contiguous United States and it is found near large bodies of open water with an abundant food supply and old-growth trees for nesting. The bald eagle is a feeder which subsists mainly on fish. It builds the largest nest of any North American bird and the largest tree nests ever recorded for any species, up to 4 m deep,2.5 m wide. Sexual maturity is attained at the age of four to five years, Bald eagles are not actually bald, the name derives from an older meaning of the word, white headed. The adult is brown with a white head and tail. The sexes are identical in plumage, but females are about 25 percent larger than males, the beak is large and hooked. The plumage of the immature is brown, the bald eagle is both the national bird and national animal of the United States of America. The bald eagle appears on its seal, in the late 20th century it was on the brink of extirpation in the contiguous United States.
Populations have since recovered and the species was removed from the U. S. governments list of endangered species on July 12,1995 and it was removed from the List of Endangered and Threatened Wildlife in the Lower 48 States on June 28,2007. The plumage of an bald eagle is evenly dark brown with a white head. The tail is long and slightly wedge-shaped. Males and females are identical in coloration, but sexual dimorphism is evident in the species. The beak and irises are bright yellow, the legs are feather-free, and the toes are short and powerful with large talons. The highly developed talon of the toe is used to pierce the vital areas of prey while it is held immobile by the front toes. The beak is large and hooked, with a yellow cere, the adult bald eagle is unmistakable in its native range. The closely related African fish eagle has a body, white head and tail