While hardware may be a source of insecurity, such as with microchip vulnerabilities maliciously introduced during the manufacturing process, hardware-based or assisted computer security also offers an alternative to software-only computer security. Using devices and methods such as dongles, trusted platform modules, intrusion-aware cases, drive locks, disabling USB ports, and mobile-enabled access may be considered more secure due to the physical access (or sophisticated backdoor access) required in order to be compromised. Each of these is covered in more detail below.


Public Safety Canada’s Canadian Cyber Incident Response Centre (CCIRC) is responsible for mitigating and responding to threats to Canada’s critical infrastructure and cyber systems. The CCIRC provides support to mitigate cyber threats, technical support to respond and recover from targeted cyber attacks, and provides online tools for members of Canada’s critical infrastructure sectors. The CCIRC posts regular cyber security bulletins on the Public Safety Canada website. The CCIRC also operates an online reporting tool where individuals and organizations can report a cyber incident. Canada's Cyber Security Strategy is part of a larger, integrated approach to critical infrastructure protection, and functions as a counterpart document to the National Strategy and Action Plan for Critical Infrastructure.


This has led to new terms such as cyberwarfare and cyberterrorism. More and more critical infrastructure is being controlled via computer programs that, while increasing efficiency, exposes new vulnerabilities. The test will be to see if governments and corporations that control critical systems such as energy, communications and other information will be able to prevent attacks before they occur. As Jay Cross, the chief scientist of the Internet Time Group, remarked, "Connectedness begets vulnerability."


On September 27, 2010, Public Safety Canada partnered with STOP.THINK.CONNECT, a coalition of non-profit, private sector, and government organizations dedicated to informing the general public on how to protect themselves online. On February 4, 2014, the Government of Canada launched the Cyber Security Cooperation Program. The program is a $1.5 million five-year initiative aimed at improving Canada’s cyber systems through grants and contributions to projects in support of this objective. Public Safety Canada aims to begin an evaluation of Canada's Cyber Security Strategy in early 2015. Public Safety Canada administers and routinely updates the GetCyberSafe portal for Canadian citizens, and carries out Cyber Security Awareness Month during October.


An unauthorized user gaining physical access to a computer is most likely able to directly download data from it. They may also compromise security by making operating system modifications, installing software worms, keyloggers, or covert listening devices. Even when the system is protected by standard security measures, these may be able to be by passed by booting another operating system or tool from a CD-ROM or other bootable media. Disk encryption and Trusted Platform Module are designed to prevent these attacks.


Clickjacking, also known as "UI redress attack or User Interface redress attack", is a malicious technique in which an attacker tricks a user into clicking on a button or link on another webpage while the user intended to click on the top level page. This is done using multiple transparent or opaque layers. The attacker is basically "hijacking" the clicks meant for the top level page and routing them to some other irrelevant page, most likely owned by someone else. A similar technique can be used to hijack keystrokes. Carefully drafting a combination of stylesheets, iframes, buttons and text boxes, a user can be led into believing that they are typing the password or other information on some authentic webpage while it is being channeled into an invisible frame controlled by the attacker.


In 1988, only 60,000 computers were connected to the Internet, and most were mainframes, minicomputers and professional workstations. On November 2, 1988, many started to slow down, because they were running a malicious code that demanded processor time and that spread itself to other computers – the first internet "computer worm". The software was traced back to 23-year-old Cornell University graduate student Robert Tappan Morris, Jr. who said 'he wanted to count how many machines were connected to the Internet'.


In 2013 and 2014, a Russian/Ukrainian hacking ring known as "Rescator" broke into Target Corporation computers in 2013, stealing roughly 40 million credit cards, and then Home Depot computers in 2014, stealing between 53 and 56 million credit card numbers. Warnings were delivered at both corporations, but ignored; physical security breaches using self checkout machines are believed to have played a large role. "The malware utilized is absolutely unsophisticated and uninteresting," says Jim Walter, director of threat intelligence operations at security technology company McAfee – meaning that the heists could have easily been stopped by existing antivirus software had administrators responded to the warnings. The size of the thefts has resulted in major attention from state and Federal United States authorities and the investigation is ongoing.


Berlin starts National Cyber Defense Initiative: On June 16, 2011, the German Minister for Home Affairs, officially opened the new German NCAZ (National Center for Cyber Defense) Nationales Cyber-Abwehrzentrum located in Bonn. The NCAZ closely cooperates with BSI (Federal Office for Information Security) Bundesamt für Sicherheit in der Informationstechnik, BKA (Federal Police Organisation) Bundeskriminalamt (Deutschland), BND (Federal Intelligence Service) Bundesnachrichtendienst, MAD (Military Intelligence Service) Amt für den Militärischen Abschirmdienst and other national organisations in Germany taking care of national security aspects. According to the Minister the primary task of the new organisation founded on February 23, 2011, is to detect and prevent attacks against the national infrastructure and mentioned incidents like Stuxnet.


Orthodox Judaism is the approach to religious Judaism which subscribes to a tradition of mass revelation and adheres to the interpretation and application of the laws and ethics of the Torah as legislated in the Talmudic texts by the Tanaim and Amoraim. These texts were subsequently developed and applied by later authorities, known as the Gaonim, Rishonim, and Acharonim. Orthodox Judaism generally includes Modern Orthodox Judaism (אורתודוקסיה מודרנית) and Ultra-Orthodox or Haredi Judaism (יהדות חרדית), but complete within is a wide range of philosophies. Although Orthodox Judaism would probably be considered the mainstream expression of Judaism prior to the 19th century, for some Orthodox Judaism is a modern self-identification that distinguishes it from traditional pre-modern Judaism.


According to the New Jersey Press Association, several media entities refrain from using the term "ultra-Orthodox", including the Religion Newswriters Association; JTA, the global Jewish news service; and the Star-Ledger, New Jersey’s largest daily newspaper. The Star-Ledger was the first mainstream newspaper to drop the term. Several local Jewish papers, including New York's Jewish Week and Philadelphia's Jewish Exponent have also dropped use of the term. According to Rabbi Shammai Engelmayer, spiritual leader of Temple Israel Community Center in Cliffside Park and former executive editor of Jewish Week, this leaves "Orthodox" as "an umbrella term that designates a very widely disparate group of people very loosely tied together by some core beliefs."


Modern Orthodoxy comprises a fairly broad spectrum of movements, each drawing on several distinct though related philosophies, which in some combination have provided the basis for all variations of the movement today. In general, Modern Orthodoxy holds that Jewish law is normative and binding, while simultaneously attaching a positive value to interaction with contemporary society. In this view, Orthodox Judaism can "be enriched" by its intersection with modernity; further, "modern society creates opportunities to be productive citizens engaged in the Divine work of transforming the world to benefit humanity". At the same time, in order to preserve the integrity of halakha, any area of "powerful inconsistency and conflict" between Torah and modern culture must be avoided. Modern Orthodoxy, additionally, assigns a central role to the "People of Israel".


Externally, Orthodox Jews can be identified by their manner of dress and family lifestyle. Orthodox women dress modestly by keeping most of their skin covered. Additionally, married women cover their hair, most commonly in the form of a scarf, also in the form of hats, bandanas, berets, snoods or, sometimes, wigs. Orthodox men wear a skullcap known as a kipa and often fringes called "tzitzit". Haredi men often grow beards and always wear black hats and suits, indoors and outdoors. However, Modern Orthodox Jews are commonly indistinguishable in their dress from those around them.


Orthodox Judaism holds that the words of the Torah, including both the Written Law (Pentateuch) and those parts of the Oral Law which are "halacha leMoshe m'Sinai", were dictated by God to Moses essentially as they exist today. The laws contained in the Written Torah were given along with detailed explanations as how to apply and interpret them, the Oral Law. Although Orthodox Jews believe that many elements of current religious law were decreed or added as "fences" around the law by the rabbis, all Orthodox Jews believe that there is an underlying core of Sinaitic law and that this core of the religious laws Orthodox Jews know today is thus directly derived from Sinai and directly reflects the Divine will. As such, Orthodox Jews believe that one must be extremely careful in interpreting Jewish law. Orthodox Judaism holds that, given Jewish law's Divine origin, no underlying principle may be compromised in accounting for changing political, social or economic conditions; in this sense, "creativity" and development in Jewish law is limited.


In reaction to the emergence of Reform Judaism, a group of traditionalist German Jews emerged in support of some of the values of the Haskalah, but also wanted to defend the classic, traditional interpretation of Jewish law and tradition. This group was led by those who opposed the establishment of a new temple in Hamburg , as reflected in the booklet "Ele Divrei HaBerit". As a group of Reform Rabbis convened in Braunschweig, Rabbi Jacob Ettlinger of Altona published a manifesto entitled "Shlomei Emunei Yisrael" in German and Hebrew, having 177 Rabbis sign on. At this time the first Orthodox Jewish periodical, "Der Treue Zions Waechter", was launched with the Hebrew supplement "Shomer Zion HaNe'eman" [1845 - 1855]. In later years it was Rav Ettlinger's students Rabbi Samson Raphael Hirsch and Rabbi Azriel Hildesheimer of Berlin who deepened the awareness and strength of Orthodox Jewry. Rabbi Samson Raphael Hirsch commented in 1854:


Jewish historians also note that certain customs of today's Orthodox are not continuations of past practice, but instead represent innovations that would have been unknown to prior generations. For example, the now-widespread haredi tradition of cutting a boy's hair for the first time on his third birthday (upshirin or upsheerin, Yiddish for "haircut") "originated as an Arab custom that parents cut a newborn boy's hair and burned it in a fire as a sacrifice," and "Jews in Palestine learned this custom from Arabs and adapted it to a special Jewish context." The Ashkenazi prohibition against eating kitniyot (grains and legumes such as rice, corn, beans, and peanuts) during Passover was explicitly rejected in the Talmud, has no known precedent before the 12th century and represented a minority position for hundreds of years thereafter, but nonetheless has remained a mandatory prohibition among Ashkenazi Orthodox Jews due to their historic adherence to the ReMA's rulings in the Shulchan Aruch.


Haredi Judaism advocates segregation from non-Jewish culture, although not from non-Jewish society entirely. It is characterised by its focus on community-wide Torah study. Haredi Orthodoxy's differences with Modern Orthodoxy usually lie in interpretation of the nature of traditional halakhic concepts and in acceptable application of these concepts. Thus, engaging in the commercial world is a legitimate means to achieving a livelihood, but individuals should participate in modern society as little as possible. The same outlook is applied with regard to obtaining degrees necessary to enter one's intended profession: where tolerated in the Haredi society, attending secular institutions of higher education is viewed as a necessary but inferior activity. Academic interest is instead to be directed toward the religious education found in the yeshiva. Both boys and girls attend school and may proceed to higher Torah study, starting anywhere between the ages of 13 and 18. A significant proportion of students, especially boys, remain in yeshiva until marriage (which is often arranged through facilitated dating – see shiduch), and many study in a kollel (Torah study institute for married men) for many years after marriage. Most Orthodox men (including many Modern Orthodox), even those not in Kollel, will study Torah daily.


Orthodox Judaism holds that on Mount Sinai, the Written Law was transmitted along with an Oral Law. The words of the Torah (Pentateuch) were spoken to Moses by God; the laws contained in this Written Torah, the "Mitzvot", were given along with detailed explanations in the oral tradition as to how to apply and interpret them. Furthermore, the Oral law includes principles designed to create new rules. The Oral law is held to be transmitted with an extremely high degree of accuracy. Jewish theologians, who choose to emphasize the more evolutionary nature of the Halacha point to a famous story in the Talmud, where Moses is miraculously transported to the House of Study of Rabbi Akiva and is clearly unable to follow the ensuing discussion.


Orthodox Judaism maintains the historical understanding of Jewish identity. A Jew is someone who was born to a Jewish mother, or who converts to Judaism in accordance with Jewish law and tradition. Orthodoxy thus rejects patrilineal descent as a means of establishing Jewish identity. Similarly, Orthodoxy strongly condemns intermarriage. Intermarriage is seen as a deliberate rejection of Judaism, and an intermarried person is effectively cut off from most of the Orthodox community. However, some Orthodox Jewish organizations do reach out to intermarried Jews.


However, there is significant disagreement within Orthodox Judaism, particularly between Haredi Judaism and Modern Orthodox Judaism, about the extent and circumstances under which the proper application of Halakha should be re-examined as a result of changing realities. As a general rule, Haredi Jews believe that when at all possible the law should be maintained as it was understood by their authorities at the haskalah, believing that it had never changed. Modern Orthodox authorities are more willing to assume that under scrupulous examination, identical principles may lead to different applications in the context of modern life. To the Orthodox Jew, halakha is a guide, God's Law, governing the structure of daily life from the moment he or she wakes up to the moment he goes to sleep. It includes codes of behaviour applicable to a broad range of circumstances (and many hypothetical ones). There are though a number of halakhic meta-principles that guide the halakhic process and in an instance of opposition between a specific halakha and a meta-principle, the meta-principle often wins out . Examples of Halakhic Meta-Principles are: "Deracheha Darchei Noam" - the ways of Torah are pleasant, "Kavod Habriyot" - basic respect for human beings, "Pikuach Nefesh" - the sanctity of human life.


According to Orthodox Judaism, Jewish law today is based on the commandments in the Torah, as viewed through the discussions and debates contained in classical rabbinic literature, especially the Mishnah and the Talmud. Orthodox Judaism thus holds that the halakha represents the "will of God", either directly, or as closely to directly as possible. The laws are from the word of God in the Torah, using a set of rules also revealed by God to Moses on Mount Sinai, and have been derived with the utmost accuracy and care, and thus the Oral Law is considered to be no less the word of God. If some of the details of Jewish law may have been lost over the millennia, they were reconstructed in accordance with internally consistent rules; see The 13 rules by which Jewish law was derived.


Hasidic or Chasidic Judaism overlaps significantly with Haredi Judaism in its engagement with the secular and commercial world, and in regard to social issues. It precedes the later and differs in its genesis and emerged focus. The movement originated in Eastern Europe (what is now Belarus and Ukraine) in the 18th century. Founded by Israel ben Eliezer, known as the Baal Shem Tov (1698–1760), it emerged in an age of persecution of the Jewish people, when a schism existed between scholarly and common European Jews. In addition to bridging this class gap, Hasidic teachings sought to reintroduce joy in the performance of the commandments and in prayer through the popularisation of Jewish mysticism (this joy had been suppressed in the intense intellectual study of the Talmud). The Ba'al Shem Tov sought to combine rigorous scholarship with more emotional mitzvah observance. In a practical sense, what distinguishes Hasidic Judaism from other forms of Haredi Judaism is the close-knit organization of Hasidic communities centered on a Rebbe (sometimes translated as "Grand Rabbi"), and various customs and modes of dress particular to each community. In some cases, there are religious ideological distinctions between Hasidic groups, as well. Another phenomenon that sets Hasidic Judaism apart from general Haredi Judaism is the strong emphasis placed on speaking Yiddish; in (many) Hasidic households and communities, Yiddish is spoken exclusively.


In contrast to the general American Jewish community, which is dwindling due to low fertility and high intermarriage and assimilation rates, the Orthodox Jewish community of the United States is growing rapidly. Among Orthodox Jews, the fertility rate stands at about 4.1 children per family, as compared to 1.9 children per family among non-Orthodox Jews, and intermarriage among Orthodox Jews is practically non-existent, standing at about 2%, in contrast to a 71% intermarriage rate among non-Orthodox Jews. In addition, Orthodox Judaism has a growing retention rate; while about half of those raised in Orthodox homes previously abandoned Orthodox Judaism, that number is declining. According to The New York Times, the high growth rate of Orthodox Jews will eventually render them the dominant demographic force in New York Jewry.


On the other hand, Orthodox Jews subscribing to Modern Orthodoxy in its American and UK incarnations, tend to be far more right-wing than both non-orthodox and other orthodox Jews. While the overwhelming majority of non-Orthodox American Jews are on average strongly liberal and supporters of the Democratic Party, the Modern Orthodox subgroup of Orthodox Judaism tends to be far more conservative, with roughly half describing themselves as political conservatives, and are mostly Republican Party supporters. Modern Orthodox Jews, compared to both the non-Orthodox American Jewry and the Haredi and Hasidic Jewry, also tend to have a stronger connection to Israel due to their attachment to Zionism.


Modern Orthodoxy, as a stream of Orthodox Judaism represented by institutions such as the U.S. National Council for Young Israel, is pro-Zionist and thus places a high national, as well as religious, significance on the State of Israel, and its affiliates are, typically, Zionist in orientation. It also practices involvement with non-Orthodox Jews that extends beyond "outreach (Kiruv)" to continued institutional relations and cooperation; see further under Torah Umadda. Other "core beliefs" are a recognition of the value and importance of secular studies, a commitment to equality of education for both men and women, and a full acceptance of the importance of being able to financially support oneself and one's family.


However, the Orthodox claim to absolute fidelity to past tradition has been challenged by scholars who contend that the Judaism of the Middle Ages bore little resemblance to that practiced by today's Orthodox. Rather, the Orthodox community, as a counterreaction to the liberalism of the Haskalah movement, began to embrace far more stringent halachic practices than their predecessors, most notably in matters of Kashrut and Passover dietary laws, where the strictest possible interpretation becomes a religious requirement, even where the Talmud explicitly prefers a more lenient position, and even where a more lenient position was practiced by prior generations.


The roots of Orthodox Judaism can be traced to the late 18th or early 19th century, when elements within German Jewry sought to reform Jewish belief and practice in the early 19th century in response to the Age of Enlightenment, Jewish Emancipation, and Haskalah. They sought to modernize education in light of contemporary scholarship. They rejected claims of the absolute divine authorship of the Torah, declaring only biblical laws concerning ethics to be binding, and stated that the rest of halakha (Jewish law) need not be viewed as normative for Jews in wider society. (see Reform Judaism).


Politically, Orthodox Jews, given their variety of movements and affiliations, tend not to conform easily to the standard left-right political spectrum, with one of the key differences between the movements stemming from the groups' attitudes to Zionism. Generally speaking, of the three key strands of Orthodox Judaism, Haredi Orthodox and Hasidic Orthodox Jews are at best ambivalent towards the ideology of Zionism and the creation of the State of Israel, and there are many groups and organisations who are outspokenly anti-Zionistic, seeing the ideology of Zionism as diametrically opposed to the teaching of the Torah, and the Zionist administration of the State of Israel, with its emphasis on militarism and nationalism, as destructive of the Judaic way of life.


In practice, the emphasis on strictness has resulted in the rise of "homogeneous enclaves" with other haredi Jews that are less likely to be threatened by assimilation and intermarriage, or even to interact with other Jews who do not share their doctrines. Nevertheless, this strategy has proved successful and the number of adherents to Orthodox Judaism, especially Haredi and Chassidic communities, has grown rapidly. Some scholars estimate more Jewish men are studying in yeshivot (Talmudic schools) and Kollelim (post-graduate Talmudical colleges for married (male) students) than at any other time in history.[citation needed]


Orthodox Judaism collectively considers itself the only true heir to the Jewish tradition. The Orthodox Jewish movements consider all non-Orthodox Jewish movements to be unacceptable deviations from authentic Judaism; both because of other denominations' doubt concerning the verbal revelation of Written and Oral Torah, and because of their rejection of Halakhic precedent as binding. As such, Orthodox Jewish groups characterize non-Orthodox forms of Judaism as heretical; see the article on Relationships between Jewish religious movements.


Although sizable Orthodox Jewish communities are located throughout the United States, many American Orthodox Jews live in New York State, particularly in the New York City Metropolitan Area. Two of the main Orthodox communities in the United States are located in New York City and Rockland County. In New York City, the neighborhoods of Borough Park, Midwood, Williamsburg, and Crown Heights, located in the borough of Brooklyn, have particularly large Orthodox communities. The most rapidly growing community of American Orthodox Jews is located in Rockland County and the Hudson Valley of New York, including the communities of Monsey, Monroe, New Square, and Kiryas Joel. There are also sizable and rapidly growing Orthodox communities throughout New Jersey, particularly in Lakewood, Teaneck, Englewood, Passaic, and Fair Lawn.


Some scholars believe that Modern Orthodoxy arose from the religious and social realities of Western European Jewry. While most Jews consider Modern Orthodoxy traditional today, some (the hareidi and hasidic groups) within the Orthodox community consider some elements to be of questionable validity. The neo-Orthodox movement holds that Hirsch's views are not accurately followed by Modern Orthodoxy. [See Torah im Derech Eretz and Torah Umadda "Relationship with Torah im Derech Eretz" for a more extensive listing.]


For guidance in practical application of Jewish law, the majority of Orthodox Jews appeal to the Shulchan Aruch ("Code of Jewish Law" composed in the 16th century by Rabbi Joseph Caro) together with its surrounding commentaries. Thus, at a general level, there is a large degree of uniformity amongst all Orthodox Jews. Concerning the details, however, there is often variance: decisions may be based on various of the standardized codes of Jewish Law that have been developed over the centuries, as well as on the various responsa. These codes and responsa may differ from each other as regards detail (and reflecting the above philosophical differences, as regards the weight assigned to these). By and large, however, the differences result from the historic dispersal of the Jews and the consequent development of differences among regions in their practices (see minhag).


Hirsch held the opinion that Judaism demands an application of Torah thought to the entire realm of human experience, including the secular disciplines. His approach was termed the Torah im Derech Eretz approach, or "neo-Orthodoxy". While insisting on strict adherence to Jewish beliefs and practices, he held that Jews should attempt to engage and influence the modern world, and encouraged those secular studies compatible with Torah thought. This pattern of religious and secular involvement has been evident at many times in Jewish history. Scholars[who?] believe it was characteristic of the Jews in Babylon during the Amoraic and Geonic periods, and likewise in early medieval Spain, shown by their engagement with both Muslim and Christian society. It appeared as the traditional response to cultural and scientific innovation.


The word "animal" comes from the Latin animalis, meaning having breath, having soul or living being. In everyday non-scientific usage the word excludes humans – that is, "animal" is often used to refer only to non-human members of the kingdom Animalia; often, only closer relatives of humans such as mammals, or mammals and other vertebrates, are meant. The biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans.


All animals have eukaryotic cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. This may be calcified to form structures like shells, bones, and spicules. During development, it forms a relatively flexible framework upon which cells can move about and be reorganized, making complex structures possible. In contrast, other multicellular organisms, like plants and fungi, have cells held in place by cell walls, and so develop by progressive growth. Also, unique to animal cells are the following intercellular junctions: tight junctions, gap junctions, and desmosomes.


Predation is a biological interaction where a predator (a heterotroph that is hunting) feeds on its prey (the organism that is attacked). Predators may or may not kill their prey prior to feeding on them, but the act of predation almost always results in the death of the prey. The other main category of consumption is detritivory, the consumption of dead organic matter. It can at times be difficult to separate the two feeding behaviours, for example, where parasitic species prey on a host organism and then lay their eggs on it for their offspring to feed on its decaying corpse. Selective pressures imposed on one another has led to an evolutionary arms race between prey and predator, resulting in various antipredator adaptations.


Among the other phyla, the Ctenophora and the Cnidaria, which includes sea anemones, corals, and jellyfish, are radially symmetric and have digestive chambers with a single opening, which serves as both the mouth and the anus. Both have distinct tissues, but they are not organized into organs. There are only two main germ layers, the ectoderm and endoderm, with only scattered cells between them. As such, these animals are sometimes called diploblastic. The tiny placozoans are similar, but they do not have a permanent digestive chamber.


Animals have several characteristics that set them apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and most protists. They are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking rigid cell walls. All animals are motile, if only at certain life stages. In most animals, embryos pass through a blastula stage, which is a characteristic exclusive to animals.


A zygote initially develops into a hollow sphere, called a blastula, which undergoes rearrangement and differentiation. In sponges, blastula larvae swim to a new location and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber, and two separate germ layers — an external ectoderm and an internal endoderm. In most cases, a mesoderm also develops between them. These germ layers then differentiate to form tissues and organs.


Some paleontologists suggest that animals appeared much earlier than the Cambrian explosion, possibly as early as 1 billion years ago. Trace fossils such as tracks and burrows found in the Tonian period indicate the presence of triploblastic worms, like metazoans, roughly as large (about 5 mm wide) and complex as earthworms. During the beginning of the Tonian period around 1 billion years ago, there was a decrease in Stromatolite diversity, which may indicate the appearance of grazing animals, since stromatolite diversity increased when grazing animals went extinct at the End Permian and End Ordovician extinction events, and decreased shortly after the grazer populations recovered. However the discovery that tracks very similar to these early trace fossils are produced today by the giant single-celled protist Gromia sphaerica casts doubt on their interpretation as evidence of early animal evolution.


Animals are generally considered to have evolved from a flagellated eukaryote. Their closest known living relatives are the choanoflagellates, collared flagellates that have a morphology similar to the choanocytes of certain sponges. Molecular studies place animals in a supergroup called the opisthokonts, which also include the choanoflagellates, fungi and a few small parasitic protists. The name comes from the posterior location of the flagellum in motile cells, such as most animal spermatozoa, whereas other eukaryotes tend to have anterior flagella.


The remaining animals form a monophyletic group called the Bilateria. For the most part, they are bilaterally symmetric, and often have a specialized head with feeding and sensory organs. The body is triploblastic, i.e. all three germ layers are well-developed, and tissues form distinct organs. The digestive chamber has two openings, a mouth and an anus, and there is also an internal body cavity called a coelom or pseudocoelom. There are exceptions to each of these characteristics, however — for instance adult echinoderms are radially symmetric, and certain parasitic worms have extremely simplified body structures.


Traditional morphological and modern molecular phylogenetic analysis have both recognized a major evolutionary transition from "non-bilaterian" animals, which are those lacking a bilaterally symmetric body plan (Porifera, Ctenophora, Cnidaria and Placozoa), to "bilaterian" animals (Bilateria) whose body plans display bilateral symmetry. The latter are further classified based on a major division between Deuterostomes and Protostomes. The relationships among non-bilaterian animals are disputed, but all bilaterian animals are thought to form a monophyletic group. Current understanding of the relationships among the major groups of animals is summarized by the following cladogram:


The Ecdysozoa are protostomes, named after the common trait of growth by moulting or ecdysis. The largest animal phylum belongs here, the Arthropoda, including insects, spiders, crabs, and their kin. All these organisms have a body divided into repeating segments, typically with paired appendages. Two smaller phyla, the Onychophora and Tardigrada, are close relatives of the arthropods and share these traits. The ecdysozoans also include the Nematoda or roundworms, perhaps the second largest animal phylum. Roundworms are typically microscopic, and occur in nearly every environment where there is water. A number are important parasites. Smaller phyla related to them are the Nematomorpha or horsehair worms, and the Kinorhyncha, Priapulida, and Loricifera. These groups have a reduced coelom, called a pseudocoelom.


Because of the great diversity found in animals, it is more economical for scientists to study a small number of chosen species so that connections can be drawn from their work and conclusions extrapolated about how animals function in general. Because they are easy to keep and breed, the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans have long been the most intensively studied metazoan model organisms, and were among the first life-forms to be genetically sequenced. This was facilitated by the severely reduced state of their genomes, but as many genes, introns, and linkages lost, these ecdysozoans can teach us little about the origins of animals in general. The extent of this type of evolution within the superphylum will be revealed by the crustacean, annelid, and molluscan genome projects currently in progress. Analysis of the starlet sea anemone genome has emphasised the importance of sponges, placozoans, and choanoflagellates, also being sequenced, in explaining the arrival of 1500 ancestral genes unique to the Eumetazoa.


The Lophotrochozoa, evolved within Protostomia, include two of the most successful animal phyla, the Mollusca and Annelida. The former, which is the second-largest animal phylum by number of described species, includes animals such as snails, clams, and squids, and the latter comprises the segmented worms, such as earthworms and leeches. These two groups have long been considered close relatives because of the common presence of trochophore larvae, but the annelids were considered closer to the arthropods because they are both segmented. Now, this is generally considered convergent evolution, owing to many morphological and genetic differences between the two phyla. The Lophotrochozoa also include the Nemertea or ribbon worms, the Sipuncula, and several phyla that have a ring of ciliated tentacles around the mouth, called a lophophore. These were traditionally grouped together as the lophophorates. but it now appears that the lophophorate group may be paraphyletic, with some closer to the nemerteans and some to the molluscs and annelids. They include the Brachiopoda or lamp shells, which are prominent in the fossil record, the Entoprocta, the Phoronida, and possibly the Bryozoa or moss animals.


Several animal phyla are recognized for their lack of bilateral symmetry, and are thought to have diverged from other animals early in evolution. Among these, the sponges (Porifera) were long thought to have diverged first, representing the oldest animal phylum. They lack the complex organization found in most other phyla. Their cells are differentiated, but in most cases not organized into distinct tissues. Sponges typically feed by drawing in water through pores. However, a series of phylogenomic studies from 2008-2015 have found support for Ctenophora, or comb jellies, as the basal lineage of animals. This result has been controversial, since it would imply that that sponges may not be so primitive, but may instead be secondarily simplified. Other researchers have argued that the placement of Ctenophora as the earliest-diverging animal phylum is a statistical anomaly caused by the high rate of evolution in ctenophore genomes.


Deuterostomes differ from protostomes in several ways. Animals from both groups possess a complete digestive tract. However, in protostomes, the first opening of the gut to appear in embryological development (the archenteron) develops into the mouth, with the anus forming secondarily. In deuterostomes the anus forms first, with the mouth developing secondarily. In most protostomes, cells simply fill in the interior of the gastrula to form the mesoderm, called schizocoelous development, but in deuterostomes, it forms through invagination of the endoderm, called enterocoelic pouching. Deuterostome embryos undergo radial cleavage during cell division, while protostomes undergo spiral cleavage.


The Platyzoa include the phylum Platyhelminthes, the flatworms. These were originally considered some of the most primitive Bilateria, but it now appears they developed from more complex ancestors. A number of parasites are included in this group, such as the flukes and tapeworms. Flatworms are acoelomates, lacking a body cavity, as are their closest relatives, the microscopic Gastrotricha. The other platyzoan phyla are mostly microscopic and pseudocoelomate. The most prominent are the Rotifera or rotifers, which are common in aqueous environments. They also include the Acanthocephala or spiny-headed worms, the Gnathostomulida, Micrognathozoa, and possibly the Cycliophora. These groups share the presence of complex jaws, from which they are called the Gnathifera.


Most animals indirectly use the energy of sunlight by eating plants or plant-eating animals. Most plants use light to convert inorganic molecules in their environment into carbohydrates, fats, proteins and other biomolecules, characteristically containing reduced carbon in the form of carbon-hydrogen bonds. Starting with carbon dioxide (CO2) and water (H2O), photosynthesis converts the energy of sunlight into chemical energy in the form of simple sugars (e.g., glucose), with the release of molecular oxygen. These sugars are then used as the building blocks for plant growth, including the production of other biomolecules. When an animal eats plants (or eats other animals which have eaten plants), the reduced carbon compounds in the food become a source of energy and building materials for the animal. They are either used directly to help the animal grow, or broken down, releasing stored solar energy, and giving the animal the energy required for motion.


The process of making beer is known as brewing. A dedicated building for the making of beer is called a brewery, though beer can be made in the home and has been for much of its history. A company that makes beer is called either a brewery or a brewing company. Beer made on a domestic scale for non-commercial reasons is classified as homebrewing regardless of where it is made, though most homebrewed beer is made in the home. Brewing beer is subject to legislation and taxation in developed countries, which from the late 19th century largely restricted brewing to a commercial operation only. However, the UK government relaxed legislation in 1963, followed by Australia in 1972 and the US in 1978, allowing homebrewing to become a popular hobby.


After boiling, the hopped wort is now cooled, ready for the yeast. In some breweries, the hopped wort may pass through a hopback, which is a small vat filled with hops, to add aromatic hop flavouring and to act as a filter; but usually the hopped wort is simply cooled for the fermenter, where the yeast is added. During fermentation, the wort becomes beer in a process which requires a week to months depending on the type of yeast and strength of the beer. In addition to producing ethanol, fine particulate matter suspended in the wort settles during fermentation. Once fermentation is complete, the yeast also settles, leaving the beer clear.


Nearly all beer includes barley malt as the majority of the starch. This is because its fibrous hull remains attached to the grain during threshing. After malting, barley is milled, which finally removes the hull, breaking it into large pieces. These pieces remain with the grain during the mash, and act as a filter bed during lautering, when sweet wort is separated from insoluble grain material. Other malted and unmalted grains (including wheat, rice, oats, and rye, and less frequently, corn and sorghum) may be used. Some brewers have produced gluten-free beer, made with sorghum with no barley malt, for those who cannot consume gluten-containing grains like wheat, barley, and rye.


A microbrewery, or craft brewery, produces a limited amount of beer. The maximum amount of beer a brewery can produce and still be classed as a microbrewery varies by region and by authority, though is usually around 15,000 barrels (1.8 megalitres, 396 thousand imperial gallons or 475 thousand US gallons) a year. A brewpub is a type of microbrewery that incorporates a pub or other eating establishment. The highest density of breweries in the world, most of them microbreweries, exists in the German Region of Franconia, especially in the district of Upper Franconia, which has about 200 breweries. The Benedictine Weihenstephan Brewery in Bavaria, Germany, can trace its roots to the year 768, as a document from that year refers to a hop garden in the area paying a tithe to the monastery. The brewery was licensed by the City of Freising in 1040, and therefore is the oldest working brewery in the world.


The alcohol in beer comes primarily from the metabolism of sugars that are produced during fermentation. The quantity of fermentable sugars in the wort and the variety of yeast used to ferment the wort are the primary factors that determine the amount of alcohol in the final beer. Additional fermentable sugars are sometimes added to increase alcohol content, and enzymes are often added to the wort for certain styles of beer (primarily "light" beers) to convert more complex carbohydrates (starches) to fermentable sugars. Alcohol is a by-product of yeast metabolism and is toxic to the yeast; typical brewing yeast cannot survive at alcohol concentrations above 12% by volume. Low temperatures and too little fermentation time decreases the effectiveness of yeasts and consequently decreases the alcohol content.


Cask-conditioned ales (or cask ales) are unfiltered and unpasteurised beers. These beers are termed "real ale" by the CAMRA organisation. Typically, when a cask arrives in a pub, it is placed horizontally on a frame called a "stillage" which is designed to hold it steady and at the right angle, and then allowed to cool to cellar temperature (typically between 11–13 °C or 52–55 °F), before being tapped and vented—a tap is driven through a (usually rubber) bung at the bottom of one end, and a hard spile or other implement is used to open a hole in the side of the cask, which is now uppermost. The act of stillaging and then venting a beer in this manner typically disturbs all the sediment, so it must be left for a suitable period to "drop" (clear) again, as well as to fully condition—this period can take anywhere from several hours to several days. At this point the beer is ready to sell, either being pulled through a beer line with a hand pump, or simply being "gravity-fed" directly into the glass.


Beer contains ethyl alcohol, the same chemical that is present in wine and distilled spirits and as such, beer consumption has short-term psychological and physiological effects on the user. Different concentrations of alcohol in the human body have different effects on a person. The effects of alcohol depend on the amount an individual has drunk, the percentage of alcohol in the beer and the timespan that the consumption took place, the amount of food eaten and whether an individual has taken other prescription, over-the-counter or street drugs, among other factors. Drinking enough to cause a blood alcohol concentration (BAC) of 0.03%-0.12% typically causes an overall improvement in mood and possible euphoria, increased self-confidence and sociability, decreased anxiety, a flushed, red appearance in the face and impaired judgment and fine muscle coordination. A BAC of 0.09% to 0.25% causes lethargy, sedation, balance problems and blurred vision. A BAC from 0.18% to 0.30% causes profound confusion, impaired speech (e.g., slurred speech), staggering, dizziness and vomiting. A BAC from 0.25% to 0.40% causes stupor, unconsciousness, anterograde amnesia, vomiting (death may occur due to inhalation of vomit (pulmonary aspiration) while unconscious and respiratory depression (potentially life-threatening). A BAC from 0.35% to 0.80% causes a coma (unconsciousness), life-threatening respiratory depression and possibly fatal alcohol poisoning. As with all alcoholic drinks, drinking while driving, operating an aircraft or heavy machinery increases the risk of an accident; many countries have penalties against drunk driving.


Beer is sold in bottles and cans; it may also be available on draught, particularly in pubs and bars. The brewing industry is a global business, consisting of several dominant multinational companies and many thousands of smaller producers ranging from brewpubs to regional breweries. The strength of beer is usually around 4% to 6% alcohol by volume (abv), although it may vary between 0.5% and 20%, with some breweries creating examples of 40% abv and above. Beer forms part of the culture of beer-drinking nations and is associated with social traditions such as beer festivals, as well as a rich pub culture involving activities like pub crawling, and pub games such as bar billiards.


Beer is composed mostly of water. Regions have water with different mineral components; as a result, different regions were originally better suited to making certain types of beer, thus giving them a regional character. For example, Dublin has hard water well-suited to making stout, such as Guinness; while the Plzeň Region has soft water well-suited to making Pilsner (pale lager), such as Pilsner Urquell. The waters of Burton in England contain gypsum, which benefits making pale ale to such a degree that brewers of pale ales will add gypsum to the local water in a process known as Burtonisation.


In 1516, William IV, Duke of Bavaria, adopted the Reinheitsgebot (purity law), perhaps the oldest food-quality regulation still in use in the 21st century, according to which the only allowed ingredients of beer are water, hops and barley-malt. Beer produced before the Industrial Revolution continued to be made and sold on a domestic scale, although by the 7th century AD, beer was also being produced and sold by European monasteries. During the Industrial Revolution, the production of beer moved from artisanal manufacture to industrial manufacture, and domestic manufacture ceased to be significant by the end of the 19th century. The development of hydrometers and thermometers changed brewing by allowing the brewer more control of the process and greater knowledge of the results.


Hops contain several characteristics that brewers desire in beer. Hops contribute a bitterness that balances the sweetness of the malt; the bitterness of beers is measured on the International Bitterness Units scale. Hops contribute floral, citrus, and herbal aromas and flavours to beer. Hops have an antibiotic effect that favours the activity of brewer's yeast over less desirable microorganisms and aids in "head retention", the length of time that a foamy head created by carbonation will last. The acidity of hops is a preservative.


The first step, where the wort is prepared by mixing the starch source (normally malted barley) with hot water, is known as "mashing". Hot water (known as "liquor" in brewing terms) is mixed with crushed malt or malts (known as "grist") in a mash tun. The mashing process takes around 1 to 2 hours, during which the starches are converted to sugars, and then the sweet wort is drained off the grains. The grains are now washed in a process known as "sparging". This washing allows the brewer to gather as much of the fermentable liquid from the grains as possible. The process of filtering the spent grain from the wort and sparge water is called wort separation. The traditional process for wort separation is lautering, in which the grain bed itself serves as the filter medium. Some modern breweries prefer the use of filter frames which allow a more finely ground grist.


The basic ingredients of beer are water; a starch source, such as malted barley, able to be saccharified (converted to sugars) then fermented (converted into ethanol and carbon dioxide); a brewer's yeast to produce the fermentation; and a flavouring such as hops. A mixture of starch sources may be used, with a secondary starch source, such as maize (corn), rice or sugar, often being termed an adjunct, especially when used as a lower-cost substitute for malted barley. Less widely used starch sources include millet, sorghum and cassava root in Africa, and potato in Brazil, and agave in Mexico, among others. The amount of each starch source in a beer recipe is collectively called the grain bill.


The first historical mention of the use of hops in beer was from 822 AD in monastery rules written by Adalhard the Elder, also known as Adalard of Corbie, though the date normally given for widespread cultivation of hops for use in beer is the thirteenth century. Before the thirteenth century, and until the sixteenth century, during which hops took over as the dominant flavouring, beer was flavoured with other plants; for instance, grains of paradise or alehoof. Combinations of various aromatic herbs, berries, and even ingredients like wormwood would be combined into a mixture known as gruit and used as hops are now used. Some beers today, such as Fraoch' by the Scottish Heather Ales company and Cervoise Lancelot by the French Brasserie-Lancelot company, use plants other than hops for flavouring.


Stout and porter are dark beers made using roasted malts or roast barley, and typically brewed with slow fermenting yeast. There are a number of variations including Baltic porter, dry stout, and Imperial stout. The name Porter was first used in 1721 to describe a dark brown beer popular with the street and river porters of London. This same beer later also became known as stout, though the word stout had been used as early as 1677. The history and development of stout and porter are intertwined.


Many beers are sold in cans, though there is considerable variation in the proportion between different countries. In Sweden in 2001, 63.9% of beer was sold in cans. People either drink from the can or pour the beer into a glass. A technology developed by Crown Holdings for the 2010 FIFA World Cup is the 'full aperture' can, so named because the entire lid is removed during the opening process, turning the can into a drinking cup. Cans protect the beer from light (thereby preventing "skunked" beer) and have a seal less prone to leaking over time than bottles. Cans were initially viewed as a technological breakthrough for maintaining the quality of a beer, then became commonly associated with less expensive, mass-produced beers, even though the quality of storage in cans is much like bottles. Plastic (PET) bottles are used by some breweries.


The product claimed to be the strongest beer made is Schorschbräu's 2011 Schorschbock 57 with 57,5%. It was preceded by The End of History, a 55% Belgian ale, made by BrewDog in 2010. The same company had previously made Sink The Bismarck!, a 41% abv IPA, and Tactical Nuclear Penguin, a 32% abv Imperial stout. Each of these beers are made using the eisbock method of fractional freezing, in which a strong ale is partially frozen and the ice is repeatedly removed, until the desired strength is reached, a process that may class the product as spirits rather than beer. The German brewery Schorschbräu's Schorschbock, a 31% abv eisbock, and Hair of the Dog's Dave, a 29% abv barley wine made in 1994, used the same fractional freezing method. A 60% abv blend of beer with whiskey was jokingly claimed as the strongest beer by a Dutch brewery in July 2010.


Most beers are cleared of yeast by filtering when packaged in bottles and cans. However, bottle conditioned beers retain some yeast—either by being unfiltered, or by being filtered and then reseeded with fresh yeast. It is usually recommended that the beer be poured slowly, leaving any yeast sediment at the bottom of the bottle. However, some drinkers prefer to pour in the yeast; this practice is customary with wheat beers. Typically, when serving a hefeweizen wheat beer, 90% of the contents are poured, and the remainder is swirled to suspend the sediment before pouring it into the glass. Alternatively, the bottle may be inverted prior to opening. Glass bottles are always used for bottle conditioned beers.


It is considered that overeating and lack of muscle tone is the main cause of a beer belly, rather than beer consumption. A 2004 study, however, found a link between binge drinking and a beer belly. But with most overconsumption, it is more a problem of improper exercise and overconsumption of carbohydrates than the product itself. Several diet books quote beer as having an undesirably high glycemic index of 110, the same as maltose; however, the maltose in beer undergoes metabolism by yeast during fermentation so that beer consists mostly of water, hop oils and only trace amounts of sugars, including maltose.


Around the world, there are many traditional and ancient starch-based drinks classed as beer. In Africa, there are various ethnic beers made from sorghum or millet, such as Oshikundu in Namibia and Tella in Ethiopia. Kyrgyzstan also has a beer made from millet; it is a low alcohol, somewhat porridge-like drink called "Bozo". Bhutan, Nepal, Tibet and Sikkim also use millet in Chhaang, a popular semi-fermented rice/millet drink in the eastern Himalayas. Further east in China are found Huangjiu and Choujiu—traditional rice-based beverages related to beer.


The earliest known chemical evidence of barley beer dates to circa 3500–3100 BC from the site of Godin Tepe in the Zagros Mountains of western Iran. Some of the earliest Sumerian writings contain references to beer; examples include a prayer to the goddess Ninkasi, known as "The Hymn to Ninkasi", which served as both a prayer as well as a method of remembering the recipe for beer in a culture with few literate people, and the ancient advice (Fill your belly. Day and night make merry) to Gilgamesh, recorded in the Epic of Gilgamesh, by the ale-wife Siduri may, at least in part, have referred to the consumption of beer. The Ebla tablets, discovered in 1974 in Ebla, Syria, show that beer was produced in the city in 2500 BC. A fermented beverage using rice and fruit was made in China around 7000 BC. Unlike sake, mould was not used to saccharify the rice (amylolytic fermentation); the rice was probably prepared for fermentation by mastication or malting.


The sweet wort collected from sparging is put into a kettle, or "copper" (so called because these vessels were traditionally made from copper), and boiled, usually for about one hour. During boiling, water in the wort evaporates, but the sugars and other components of the wort remain; this allows more efficient use of the starch sources in the beer. Boiling also destroys any remaining enzymes left over from the mashing stage. Hops are added during boiling as a source of bitterness, flavour and aroma. Hops may be added at more than one point during the boil. The longer the hops are boiled, the more bitterness they contribute, but the less hop flavour and aroma remains in the beer.


The starch source in a beer provides the fermentable material and is a key determinant of the strength and flavour of the beer. The most common starch source used in beer is malted grain. Grain is malted by soaking it in water, allowing it to begin germination, and then drying the partially germinated grain in a kiln. Malting grain produces enzymes that convert starches in the grain into fermentable sugars. Different roasting times and temperatures are used to produce different colours of malt from the same grain. Darker malts will produce darker beers.


The brewing industry is a global business, consisting of several dominant multinational companies and many thousands of smaller producers ranging from brewpubs to regional breweries. More than 133 billion litres (35 billion gallons) are sold per year—producing total global revenues of $294.5 billion (£147.7 billion) in 2006. The history of breweries has been one of absorbing smaller breweries in order to ensure economy of scale. In 2002 South African Breweries bought the North American Miller Brewing Company to found SABMiller, becoming the second largest brewery, after North American Anheuser-Bush. In 2004 the Belgian Interbrew was the third largest brewery by volume and the Brazilian AmBev was the fifth largest. They merged into InBev, becoming the largest brewery. In 2007, SABMiller surpassed InBev and Anheuser-Bush when it acquired Royal Grolsch, brewer of Dutch premium beer brand Grolsch in 2007. In 2008, InBev (the second-largest) bought Anheuser-Busch (the third largest), the new Anheuser-Busch InBev company became again the largest brewer in the world. As of 2015[update] AB InBev is the largest brewery, with SABMiller second, and Heineken International third.


Beer ranges from less than 3% alcohol by volume (abv) to around 14% abv, though this strength can be increased to around 20% by re-pitching with champagne yeast, and to 55% abv by the freeze-distilling process. The alcohol content of beer varies by local practice or beer style. The pale lagers that most consumers are familiar with fall in the range of 4–6%, with a typical abv of 5%. The customary strength of British ales is quite low, with many session beers being around 4% abv. Some beers, such as table beer are of such low alcohol content (1%–4%) that they are served instead of soft drinks in some schools.


In many societies, beer is the most popular alcoholic drink. Various social traditions and activities are associated with beer drinking, such as playing cards, darts, or other pub games; attending beer festivals; engaging in zythology (the study of beer); visiting a series of pubs in one evening; visiting breweries; beer-oriented tourism; or rating beer. Drinking games, such as beer pong, are also popular. A relatively new profession is that of the beer sommelier, who informs restaurant patrons about beers and food pairings.


Beer is the world's most widely consumed and likely the oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. The production of beer is called brewing, which involves the fermentation of starches, mainly derived from cereal grains—most commonly malted barley, although wheat, maize (corn), and rice are widely used. Most beer is flavoured with hops, which add bitterness and act as a natural preservative, though other flavourings such as herbs or fruit may occasionally be included. The fermentation process causes a natural carbonation effect which is often removed during processing, and replaced with forced carbonation. Some of humanity's earliest known writings refer to the production and distribution of beer: the Code of Hammurabi included laws regulating beer and beer parlours, and "The Hymn to Ninkasi", a prayer to the Mesopotamian goddess of beer, served as both a prayer and as a method of remembering the recipe for beer in a culture with few literate people.


Beer was spread through Europe by Germanic and Celtic tribes as far back as 3000 BC, and it was mainly brewed on a domestic scale. The product that the early Europeans drank might not be recognised as beer by most people today. Alongside the basic starch source, the early European beers might contain fruits, honey, numerous types of plants, spices and other substances such as narcotic herbs. What they did not contain was hops, as that was a later addition, first mentioned in Europe around 822 by a Carolingian Abbot and again in 1067 by Abbess Hildegard of Bingen.


The word ale comes from Old English ealu (plural ealoþ), in turn from Proto-Germanic *alu (plural *aluþ), ultimately from the Proto-Indo-European base *h₂elut-, which holds connotations of "sorcery, magic, possession, intoxication". The word beer comes from Old English bēor, from Proto-Germanic *beuzą, probably from Proto-Indo-European *bʰeusóm, originally "brewer's yeast, beer dregs", although other theories have been provided connecting the word with Old English bēow, "barley", or Latin bibere, "to drink". On the currency of two words for the same thing in the Germanic languages, the 12th-century Old Icelandic poem Alvíssmál says, "Ale it is called among men, but among the gods, beer."


The strength of beers has climbed during the later years of the 20th century. Vetter 33, a 10.5% abv (33 degrees Plato, hence Vetter "33") doppelbock, was listed in the 1994 Guinness Book of World Records as the strongest beer at that time, though Samichlaus, by the Swiss brewer Hürlimann, had also been listed by the Guinness Book of World Records as the strongest at 14% abv. Since then, some brewers have used champagne yeasts to increase the alcohol content of their beers. Samuel Adams reached 20% abv with Millennium, and then surpassed that amount to 25.6% abv with Utopias. The strongest beer brewed in Britain was Baz's Super Brew by Parish Brewery, a 23% abv beer. In September 2011, the Scottish brewery BrewDog produced Ghost Deer, which, at 28%, they claim to be the world's strongest beer produced by fermentation alone.


Draught beer's environmental impact can be 68% lower than bottled beer due to packaging differences. A life cycle study of one beer brand, including grain production, brewing, bottling, distribution and waste management, shows that the CO2 emissions from a 6-pack of micro-brew beer is about 3 kilograms (6.6 pounds). The loss of natural habitat potential from the 6-pack of micro-brew beer is estimated to be 2.5 square meters (26 square feet). Downstream emissions from distribution, retail, storage and disposal of waste can be over 45% of a bottled micro-brew beer's CO2 emissions. Where legal, the use of a refillable jug, reusable bottle or other reusable containers to transport draught beer from a store or a bar, rather than buying pre-bottled beer, can reduce the environmental impact of beer consumption.


Drinking chilled beer began with the development of artificial refrigeration and by the 1870s, was spread in those countries that concentrated on brewing pale lager. Chilling beer makes it more refreshing, though below 15.5 °C the chilling starts to reduce taste awareness and reduces it significantly below 10 °C (50 °F). Beer served unchilled—either cool or at room temperature, reveal more of their flavours. Cask Marque, a non-profit UK beer organisation, has set a temperature standard range of 12°–14 °C (53°–57 °F) for cask ales to be served.


The main active ingredient of beer is alcohol, and therefore, the health effects of alcohol apply to beer. Consumption of small quantities of alcohol (less than one drink in women and two in men) is associated with a decreased risk of cardiac disease, stroke and diabetes mellitus. The long term health effects of continuous, moderate or heavy alcohol consumption include the risk of developing alcoholism and alcoholic liver disease. A total of 3.3 million deaths (5.9% of all deaths) are believed to be due to alcohol. Alcoholism often reduces a person's life expectancy by around ten years. Alcohol use is the third leading cause of early death in the United States.


A study published in the Neuropsychopharmacology journal in 2013 revealed the finding that the flavour of beer alone could provoke dopamine activity in the brain of the male participants, who wanted to drink more as a result. The 49 men in the study were subject to positron emission tomography scans, while a computer-controlled device sprayed minute amounts of beer, water and a sports drink onto their tongues. Compared with the taste of the sports drink, the taste of beer significantly increased the participants desire to drink. Test results indicated that the flavour of the beer triggered a dopamine release, even though alcohol content in the spray was insufficient for the purpose of becoming intoxicated.


The biggest change in this year's census was in racial classification. Enumerators were instructed to no longer use the "Mulatto" classification. Instead, they were given special instructions for reporting the race of interracial persons. A person with both white and black ancestry (termed "blood") was to be recorded as "Negro," no matter the fraction of that lineage (the "one-drop rule"). A person of mixed black and American Indian ancestry was also to be recorded as "Neg" (for "Negro") unless he was considered to be "predominantly" American Indian and accepted as such within the community. A person with both White and American Indian ancestry was to be recorded as an Indian, unless his American Indian ancestry was small, and he was accepted as white within the community. In all situations in which a person had White and some other racial ancestry, he was to be reported as that other race. Persons who had minority interracial ancestry were to be reported as the race of their father.


Race was asked differently in the Census 2000 in several other ways than previously. Most significantly, respondents were given the option of selecting one or more race categories to indicate racial identities. Data show that nearly seven million Americans identified as members of two or more races. Because of these changes, the Census 2000 data on race are not directly comparable with data from the 1990 census or earlier censuses. Use of caution is therefore recommended when interpreting changes in the racial composition of the US population over time.


In September 1997, during the process of revision of racial categories previously declared by OMB directive no. 15, the American Anthropological Association (AAA) recommended that OMB combine the "race" and "ethnicity" categories into one question to appear as "race/ethnicity" for the 2000 US Census. The Interagency Committee agreed, stating that "race" and "ethnicity" were not sufficiently defined and "that many respondents conceptualize 'race' and 'ethnicity' as one in the same  [sic] underscor[ing] the need to consolidate these terms into one category, using a term that is more meaningful to the American people."


The racial categories represent a social-political construct for the race or races that respondents consider themselves to be and "generally reflect a social definition of race recognized in this country." OMB defines the concept of race as outlined for the U.S. Census as not "scientific or anthropological" and takes into account "social and cultural characteristics as well as ancestry", using "appropriate scientific methodologies" that are not "primarily biological or genetic in reference." The race categories include both racial and national-origin groups.


Race and ethnicity are considered separate and distinct identities, with Hispanic or Latino origin asked as a separate question. Thus, in addition to their race or races, all respondents are categorized by membership in one of two ethnic categories, which are "Hispanic or Latino" and "Not Hispanic or Latino". However, the practice of separating "race" and "ethnicity" as different categories has been criticized both by the American Anthropological Association and members of U.S. Commission on Civil Rights.


President Franklin D. Roosevelt promoted a "good neighbor" policy that sought better relations with Mexico. In 1935 a federal judge ruled that three Mexican immigrants were ineligible for citizenship because they were not white, as required by federal law. Mexico protested, and Roosevelt decided to circumvent the decision and make sure the federal government treated Hispanics as white. The State Department, the Census Bureau, the Labor Department, and other government agencies therefore made sure to uniformly classify people of Mexican descent as white. This policy encouraged the League of United Latin American Citizens in its quest to minimize discrimination by asserting their whiteness.


In 1997, OMB issued a Federal Register notice regarding revisions to the standards for the classification of federal data on race and ethnicity. OMB developed race and ethnic standards in order to provide "consistent data on race and ethnicity throughout the Federal Government. The development of the data standards stem in large measure from new responsibilities to enforce civil rights laws." Among the changes, OMB issued the instruction to "mark one or more races" after noting evidence of increasing numbers of interracial children and wanting to capture the diversity in a measurable way and having received requests by people who wanted to be able to acknowledge their or their children's full ancestry rather than identifying with only one group. Prior to this decision, the Census and other government data collections asked people to report only one race.


The 1850 census saw a dramatic shift in the way information about residents was collected. For the first time, free persons were listed individually instead of by head of household. There were two questionnaires: one for free inhabitants and one for slaves. The question on the free inhabitants schedule about color was a column that was to be left blank if a person was white, marked "B" if a person was black, and marked "M" if a person was mulatto. Slaves were listed by owner, and classified by gender and age, not individually, and the question about color was a column that was to be marked with a "B" if the slave was black and an "M" if mulatto.


Although used in the Census and the American Community Survey, "Some other race" is not an official race, and the Bureau considered eliminating it prior to the 2000 Census. As the 2010 census form did not contain the question titled "Ancestry" found in prior censuses, there were campaigns to get non-Hispanic West Indian Americans, Turkish Americans, Armenian Americans, Arab Americans and Iranian Americans to indicate their ethnic or national background through the race question, specifically the "Some other race" category.


"Data on ethnic groups are important for putting into effect a number of federal statutes (i.e., enforcing bilingual election rules under the Voting Rights Act; monitoring and enforcing equal employment opportunities under the Civil Rights Act). Data on Ethnic Groups are also needed by local governments to run programs and meet legislative requirements (i.e., identifying segments of the population who may not be receiving medical services under the Public Health Act; evaluating whether financial institutions are meeting the credit needs of minority populations under the Community Reinvestment Act)."


For 1890, the Census Office changed the design of the population questionnaire. Residents were still listed individually, but a new questionnaire sheet was used for each family. Additionally, this was the first year that the census distinguished between different East Asian races, such as Japanese and Chinese, due to increased immigration. This census also marked the beginning of the term "race" in the questionnaires. Enumerators were instructed to write "White," "Black," "Mulatto," "Quadroon," "Octoroon," "Chinese," "Japanese," or "Indian."


The federal government of the United States has mandated that "in data collection and presentation, federal agencies are required to use a minimum of two ethnicities: 'Hispanic or Latino' and 'Not Hispanic or Latino'." The Census Bureau defines "Hispanic or Latino" as "a person of Cuban, Mexican, Puerto Rican, South or Central American or other Spanish culture or origin regardless of race." For discussion of the meaning and scope of the Hispanic or Latino ethnicity, see the Hispanic and Latino Americans and Racial and ethnic demographics of the United States articles.


Unlike the Spanish milled dollar the U.S. dollar is based upon a decimal system of values. In addition to the dollar the coinage act officially established monetary units of mill or one-thousandth of a dollar (symbol ₥), cent or one-hundredth of a dollar (symbol ¢), dime or one-tenth of a dollar, and eagle or ten dollars, with prescribed weights and composition of gold, silver, or copper for each. It was proposed in the mid-1800s that one hundred dollars be known as a union, but no union coins were ever struck and only patterns for the $50 half union exist. However, only cents are in everyday use as divisions of the dollar; "dime" is used solely as the name of the coin with the value of 10¢, while "eagle" and "mill" are largely unknown to the general public, though mills are sometimes used in matters of tax levies, and gasoline prices are usually in the form of $X.XX9 per gallon, e.g., $3.599, sometimes written as $3.599⁄10. When currently issued in circulating form, denominations equal to or less than a dollar are emitted as U.S. coins while denominations equal to or greater than a dollar are emitted as Federal Reserve notes (with the exception of gold, silver and platinum coins valued up to $100 as legal tender, but worth far more as bullion). Both one-dollar coins and notes are produced today, although the note form is significantly more common. In the past, "paper money" was occasionally issued in denominations less than a dollar (fractional currency) and gold coins were issued for circulation up to the value of $20 (known as the "double eagle", discontinued in the 1930s). The term eagle was used in the Coinage Act of 1792 for the denomination of ten dollars, and subsequently was used in naming gold coins. Paper currency less than one dollar in denomination, known as "fractional currency", was also sometimes pejoratively referred to as "shinplasters". In 1854, James Guthrie, then Secretary of the Treasury, proposed creating $100, $50 and $25 gold coins, which were referred to as a "Union", "Half Union", and "Quarter Union", thus implying a denomination of 1 Union = $100.


The symbol $, usually written before the numerical amount, is used for the U.S. dollar (as well as for many other currencies). The sign was the result of a late 18th-century evolution of the scribal abbreviation "ps" for the peso, the common name for the Spanish dollars that were in wide circulation in the New World from the 16th to the 19th centuries. These Spanish pesos or dollars were minted in Spanish America, namely in Mexico City, Potosí, Bolivia; and Lima, Peru. The p and the s eventually came to be written over each other giving rise to $.


Though still predominantly green, post-2004 series incorporate other colors to better distinguish different denominations. As a result of a 2008 decision in an accessibility lawsuit filed by the American Council of the Blind, the Bureau of Engraving and Printing is planning to implement a raised tactile feature in the next redesign of each note, except the $1 and the version of the $100 bill already in process. It also plans larger, higher-contrast numerals, more color differences, and distribution of currency readers to assist the visually impaired during the transition period.


The Constitution of the United States of America provides that the United States Congress has the power "To coin money". Laws implementing this power are currently codified at 31 U.S.C. § 5112. Section 5112 prescribes the forms, in which the United States dollars should be issued. These coins are both designated in Section 5112 as "legal tender" in payment of debts. The Sacagawea dollar is one example of the copper alloy dollar. The pure silver dollar is known as the American Silver Eagle. Section 5112 also provides for the minting and issuance of other coins, which have values ranging from one cent to 50 dollars. These other coins are more fully described in Coins of the United States dollar.


In the 16th century, Count Hieronymus Schlick of Bohemia began minting coins known as Joachimstalers (from German thal, or nowadays usually Tal, "valley", cognate with "dale" in English), named for Joachimstal, the valley where the silver was mined (St. Joachim's Valley, now Jáchymov; then part of the Kingdom of Bohemia, now part of the Czech Republic). Joachimstaler was later shortened to the German Taler, a word that eventually found its way into Danish and Swedish as daler, Norwegian as dalar and daler, Dutch as daler or daalder, Ethiopian as ታላሪ (talari), Hungarian as tallér, Italian as tallero, and English as dollar. Alternatively, thaler is said to come from the German coin Guldengroschen ("great guilder", being of silver but equal in value to a gold guilder), minted from the silver from Joachimsthal.


The early currency of the United States did not exhibit faces of presidents, as is the custom now; although today, by law, only the portrait of a deceased individual may appear on United States currency. In fact, the newly formed government was against having portraits of leaders on the currency, a practice compared to the policies of European monarchs. The currency as we know it today did not get the faces they currently have until after the early 20th century; before that "heads" side of coinage used profile faces and striding, seated, and standing figures from Greek and Roman mythology and composite Native Americans. The last coins to be converted to profiles of historic Americans were the dime (1946) and the Dollar (1971).


In 1862, paper money was issued without the backing of precious metals, due to the Civil War. Silver and gold coins continued to be issued and in 1878 the link between paper money and coins was reinstated. This disconnection from gold and silver backing also occurred during the War of 1812. The use of paper money not backed by precious metals had also occurred under the Articles of Confederation from 1777 to 1788. With no solid backing and being easily counterfeited, the continentals quickly lost their value, giving rise to the phrase "not worth a continental". This was a primary reason for the "No state shall... make any thing but gold and silver coin a tender in payment of debts" clause in article 1, section 10 of the United States Constitution.


In February 2007, the U.S. Mint, under the Presidential $1 Coin Act of 2005, introduced a new $1 U.S. Presidential dollar coin. Based on the success of the "50 State Quarters" series, the new coin features a sequence of presidents in order of their inaugurations, starting with George Washington, on the obverse side. The reverse side features the Statue of Liberty. To allow for larger, more detailed portraits, the traditional inscriptions of "E Pluribus Unum", "In God We Trust", the year of minting or issuance, and the mint mark will be inscribed on the edge of the coin instead of the face. This feature, similar to the edge inscriptions seen on the British £1 coin, is not usually associated with U.S. coin designs. The inscription "Liberty" has been eliminated, with the Statue of Liberty serving as a sufficient replacement. In addition, due to the nature of U.S. coins, this will be the first time there will be circulating U.S. coins of different denominations with the same president featured on the obverse (heads) side (Lincoln/penny, Jefferson/nickel, Franklin D. Roosevelt/dime, Washington/quarter, Kennedy/half dollar, and Eisenhower/dollar). Another unusual fact about the new $1 coin is Grover Cleveland will have two coins with his portrait issued due to the fact he was the only U.S. President to be elected to two non-consecutive terms.


When the Federal Reserve makes a purchase, it credits the seller's reserve account (with the Federal Reserve). This money is not transferred from any existing funds—it is at this point that the Federal Reserve has created new high-powered money. Commercial banks can freely withdraw in cash any excess reserves from their reserve account at the Federal Reserve. To fulfill those requests, the Federal Reserve places an order for printed money from the U.S. Treasury Department. The Treasury Department in turn sends these requests to the Bureau of Engraving and Printing (to print new dollar bills) and the Bureau of the Mint (to stamp the coins).


The value of the U.S. dollar declined significantly during wartime, especially during the American Civil War, World War I, and World War II. The Federal Reserve, which was established in 1913, was designed to furnish an "elastic" currency subject to "substantial changes of quantity over short periods", which differed significantly from previous forms of high-powered money such as gold, national bank notes, and silver coins. Over the very long run, the prior gold standard kept prices stable—for instance, the price level and the value of the U.S. dollar in 1914 was not very different from the price level in the 1880s. The Federal Reserve initially succeeded in maintaining the value of the U.S. dollar and price stability, reversing the inflation caused by the First World War and stabilizing the value of the dollar during the 1920s, before presiding over a 30% deflation in U.S. prices in the 1930s.


There is ongoing debate about whether central banks should target zero inflation (which would mean a constant value for the U.S. dollar over time) or low, stable inflation (which would mean a continuously but slowly declining value of the dollar over time, as is the case now). Although some economists are in favor of a zero inflation policy and therefore a constant value for the U.S. dollar, others contend that such a policy limits the ability of the central bank to control interest rates and stimulate the economy when needed.


The word "dollar" is one of the words in the first paragraph of Section 9 of Article 1 of the U.S. Constitution. In that context, "dollars" is a reference to the Spanish milled dollar, a coin that had a monetary value of 8 Spanish units of currency, or reales. In 1792 the U.S. Congress adopted legislation titled An act establishing a mint, and regulating the Coins of the United States. Section 9 of that act authorized the production of various coins, including "DOLLARS OR UNITS—each to be of the value of a Spanish milled dollar as the same is now current, and to contain three hundred and seventy-one grains and four sixteenth parts of a grain of pure, or four hundred and sixteen grains of standard silver". Section 20 of the act provided, "That the money of account of the United States shall be expressed in dollars, or units... and that all accounts in the public offices and all proceedings in the courts of the United States shall be kept and had in conformity to this regulation". In other words, this act designated the United States dollar as the unit of currency of the United States.


A "grand", sometimes shortened to simply "G", is a common term for the amount of $1,000. The suffix "K" or "k" (from "kilo-") is also commonly used to denote this amount (such as "$10k" to mean $10,000). However, the $1,000 note is no longer in general use. A "large" or "stack", it is usually a reference to a multiple of $1,000 (such as "fifty large" meaning $50,000). The $100 note is nicknamed "Benjamin", "Benji", "Ben", or "Franklin" (after Benjamin Franklin), "C-note" (C being the Roman numeral for 100), "Century note" or "bill" (e.g. "two bills" being $200). The $50 note is occasionally called a "yardstick" or a "grant" (after President Ulysses S. Grant, pictured on the obverse). The $20 note is referred to as a "double sawbuck", "Jackson" (after Andrew Jackson), or "double eagle". The $10 note is referred to as a "sawbuck", "ten-spot" or "Hamilton" (after Alexander Hamilton). The $5 note as "Lincoln", "fin", "fiver" or "five-spot". The infrequently-used $2 note is sometimes called "deuce", "Tom", or "Jefferson" (after Thomas Jefferson). The $1 note as a "single" or "buck". The dollar has also been, referred to as a "bone" and "bones" in plural (e.g. "twenty bones" is equal to $20). The newer designs, with portraits displayed in the main body of the obverse rather than in cameo insets upon paper color-coded by denomination, are sometimes referred to as "bigface" notes or "Monopoly money".


The U.S. dollar was created by the Constitution and defined by the Coinage Act of 1792. It specified a "dollar" to be based in the Spanish milled dollar and of 371 grains and 4 sixteenths part of a grain of pure or 416 grains (27.0 g) of standard silver and an "eagle" to be 247 and 4 eighths of a grain or 270 grains (17 g) of gold (again depending on purity). The choice of the value 371 grains arose from Alexander Hamilton's decision to base the new American unit on the average weight of a selection of worn Spanish dollars. Hamilton got the treasury to weigh a sample of Spanish dollars and the average weight came out to be 371 grains. A new Spanish dollar was usually about 377 grains in weight, and so the new U.S. dollar was at a slight discount in relation to the Spanish dollar.


The United States Mint produces Proof Sets specifically for collectors and speculators. Silver Proofs tend to be the standard designs but with the dime, quarter, and half dollar containing 90% silver. Starting in 1983 and ending in 1997, the Mint also produced proof sets containing the year's commemorative coins alongside the regular coins. Another type of proof set is the Presidential Dollar Proof Set where four special $1 coins are minted each year featuring a president. Because of budget constraints and increasing stockpiles of these relatively unpopular coins, the production of new Presidential dollar coins for circulation was suspended on December 13, 2011, by U.S. Treasury Secretary Timothy F. Geithner. Future minting of such coins will be made solely for collectors.


The Constitution provides that "a regular Statement and Account of the Receipts and Expenditures of all public Money shall be published from time to time". That provision of the Constitution is made specific by Section 331 of Title 31 of the United States Code. The sums of money reported in the "Statements" are currently being expressed in U.S. dollars (for example, see the 2009 Financial Report of the United States Government). The U.S. dollar may therefore be described as the unit of account of the United States.


Currently printed denominations are $1, $2, $5, $10, $20, $50, and $100. Notes above the $100 denomination stopped being printed in 1946 and were officially withdrawn from circulation in 1969. These notes were used primarily in inter-bank transactions or by organized crime; it was the latter usage that prompted President Richard Nixon to issue an executive order in 1969 halting their use. With the advent of electronic banking, they became less necessary. Notes in denominations of $500, $1,000, $5,000, $10,000 and $100,000 were all produced at one time; see large denomination bills in U.S. currency for details. These notes are now collectors' items and are worth more than their face value to collectors.


The colloquialism "buck"(s) (much like the British word "quid"(s, pl) for the pound sterling) is often used to refer to dollars of various nations, including the U.S. dollar. This term, dating to the 18th century, may have originated with the colonial leather trade. It may also have originated from a poker term. "Greenback" is another nickname originally applied specifically to the 19th century Demand Note dollars created by Abraham Lincoln to finance the costs of the Civil War for the North. The original note was printed in black and green on the back side. It is still used to refer to the U.S. dollar (but not to the dollars of other countries). Other well-known names of the dollar as a whole in denominations include "greenmail", "green" and "dead presidents" (the last because deceased presidents are pictured on most bills).


The value of the U.S. dollar was therefore no longer anchored to gold, and it fell upon the Federal Reserve to maintain the value of the U.S. currency. The Federal Reserve, however, continued to increase the money supply, resulting in stagflation and a rapidly declining value of the U.S. dollar in the 1970s. This was largely due to the prevailing economic view at the time that inflation and real economic growth were linked (the Phillips curve), and so inflation was regarded as relatively benign. Between 1965 and 1981, the U.S. dollar lost two thirds of its value.


The dollar was first based on the value and look of the Spanish dollar, used widely in Spanish America from the 16th to the 19th centuries. The first dollar coins issued by the United States Mint (founded 1792) were similar in size and composition to the Spanish dollar, minted in Mexico and Peru. The Spanish, U.S. silver dollars, and later, Mexican silver pesos circulated side by side in the United States, and the Spanish dollar and Mexican peso remained legal tender until the Coinage Act of 1857. The coinage of various English colonies also circulated. The lion dollar was popular in the Dutch New Netherland Colony (New York), but the lion dollar also circulated throughout the English colonies during the 17th century and early 18th century. Examples circulating in the colonies were usually worn so that the design was not fully distinguishable, thus they were sometimes referred to as "dog dollars".


The Gold Standard Act of 1900 abandoned the bimetallic standard and defined the dollar as 23.22 grains (1.505 g) of gold, equivalent to setting the price of 1 troy ounce of gold at $20.67. Silver coins continued to be issued for circulation until 1964, when all silver was removed from dimes and quarters, and the half dollar was reduced to 40% silver. Silver half dollars were last issued for circulation in 1970. Gold coins were confiscated by Executive Order 6102 issued in 1933 by Franklin Roosevelt. The gold standard was changed to 13.71 grains (0.888 g), equivalent to setting the price of 1 troy ounce of gold at $35. This standard persisted until 1968.


Early releases of the Washington coin included error coins shipped primarily from the Philadelphia mint to Florida and Tennessee banks. Highly sought after by collectors, and trading for as much as $850 each within a week of discovery, the error coins were identified by the absence of the edge impressions "E PLURIBUS UNUM IN GOD WE TRUST 2007 P". The mint of origin is generally accepted to be mostly Philadelphia, although identifying the source mint is impossible without opening a mint pack also containing marked units. Edge lettering is minted in both orientations with respect to "heads", some amateur collectors were initially duped into buying "upside down lettering error" coins. Some cynics also erroneously point out that the Federal Reserve makes more profit from dollar bills than dollar coins because they wear out in a few years, whereas coins are more permanent. The fallacy of this argument arises because new notes printed to replace worn out notes, which have been withdrawn from circulation, bring in no net revenue to the government to offset the costs of printing new notes and destroying the old ones. As most vending machines are incapable of making change in banknotes, they commonly accept only $1 bills, though a few will give change in dollar coins.


The U.S. Constitution provides that Congress shall have the power to "borrow money on the credit of the United States". Congress has exercised that power by authorizing Federal Reserve Banks to issue Federal Reserve Notes. Those notes are "obligations of the United States" and "shall be redeemed in lawful money on demand at the Treasury Department of the United States, in the city of Washington, District of Columbia, or at any Federal Reserve bank". Federal Reserve Notes are designated by law as "legal tender" for the payment of debts. Congress has also authorized the issuance of more than 10 other types of banknotes, including the United States Note and the Federal Reserve Bank Note. The Federal Reserve Note is the only type that remains in circulation since the 1970s.


Usually, the short-term goal of open market operations is to achieve a specific short-term interest rate target. In other instances, monetary policy might instead entail the targeting of a specific exchange rate relative to some foreign currency or else relative to gold. For example, in the case of the United States the Federal Reserve targets the federal funds rate, the rate at which member banks lend to one another overnight. The other primary means of conducting monetary policy include: (i) Discount window lending (as lender of last resort); (ii) Fractional deposit lending (changes in the reserve requirement); (iii) Moral suasion (cajoling certain market players to achieve specified outcomes); (iv) "Open mouth operations" (talking monetary policy with the market).


Under the Bretton Woods system established after World War II, the value of gold was fixed to $35 per ounce, and the value of the U.S. dollar was thus anchored to the value of gold. Rising government spending in the 1960s, however, led to doubts about the ability of the United States to maintain this convertibility, gold stocks dwindled as banks and international investors began to convert dollars to gold, and as a result the value of the dollar began to decline. Facing an emerging currency crisis and the imminent danger that the United States would no longer be able to redeem dollars for gold, gold convertibility was finally terminated in 1971 by President Nixon, resulting in the "Nixon shock".


The U.S. dollar is fiat money. It is the currency most used in international transactions and is the world's most dominant reserve currency. Several countries use it as their official currency, and in many others it is the de facto currency. Besides the United States, it is also used as the sole currency in two British Overseas Territories in the Caribbean: the British Virgin Islands and the Turks and Caicos islands. A few countries use only the U.S. Dollar for paper money, while the country mints its own coins, or also accepts U.S. coins that can be used as payment in U.S. dollars, such as the Susan B. Anthony dollar.


Today, USD notes are made from cotton fiber paper, unlike most common paper, which is made of wood fiber. U.S. coins are produced by the United States Mint. U.S. dollar banknotes are printed by the Bureau of Engraving and Printing and, since 1914, have been issued by the Federal Reserve. The "large-sized notes" issued before 1928 measured 7.42 inches (188 mm) by 3.125 inches (79.4 mm); small-sized notes, introduced that year, measure 6.14 inches (156 mm) by 2.61 inches (66 mm) by 0.0043 inches (0.11 mm). When the current, smaller sized U.S. currency was introduced it was referred to as Philippine-sized currency because the Philippines had previously adopted the same size for its legal currency.


From 1792, when the Mint Act was passed, the dollar was defined as 371.25 grains (24.056 g) of silver. Many historians[who?] erroneously assume gold was standardized at a fixed rate in parity with silver; however, there is no evidence of Congress making this law. This has to do with Alexander Hamilton's suggestion to Congress of a fixed 15:1 ratio of silver to gold, respectively. The gold coins that were minted however, were not given any denomination whatsoever and traded for a market value relative to the Congressional standard of the silver dollar. 1834 saw a shift in the gold standard to 23.2 grains (1.50 g), followed by a slight adjustment to 23.22 grains (1.505 g) in 1837 (16:1 ratio).[citation needed]


Technically, all these coins are still legal tender at face value, though some are far more valuable today for their numismatic value, and for gold and silver coins, their precious metal value. From 1965 to 1970 the Kennedy half dollar was the only circulating coin with any silver content, which was removed in 1971 and replaced with cupronickel. However, since 1992, the U.S. Mint has produced special Silver Proof Sets in addition to the regular yearly proof sets with silver dimes, quarters, and half dollars in place of the standard copper-nickel versions. In addition, an experimental $4.00 (Stella) coin was also minted in 1879, but never placed into circulation, and is properly considered to be a pattern rather than an actual coin denomination.


Dollar coins have not been very popular in the United States. Silver dollars were minted intermittently from 1794 through 1935; a copper-nickel dollar of the same large size, featuring President Dwight D. Eisenhower, was minted from 1971 through 1978. Gold dollars were also minted in the 19th century. The Susan B. Anthony dollar coin was introduced in 1979; these proved to be unpopular because they were often mistaken for quarters, due to their nearly equal size, their milled edge, and their similar color. Minting of these dollars for circulation was suspended in 1980 (collectors' pieces were struck in 1981), but, as with all past U.S. coins, they remain legal tender. As the number of Anthony dollars held by the Federal Reserve and dispensed primarily to make change in postal and transit vending machines had been virtually exhausted, additional Anthony dollars were struck in 1999. In 2000, a new $1 coin, featuring Sacagawea, (the Sacagawea dollar) was introduced, which corrected some of the problems of the Anthony dollar by having a smooth edge and a gold color, without requiring changes to vending machines that accept the Anthony dollar. However, this new coin has failed to achieve the popularity of the still-existing $1 bill and is rarely used in daily transactions. The failure to simultaneously withdraw the dollar bill and weak publicity efforts have been cited by coin proponents as primary reasons for the failure of the dollar coin to gain popular support.