text:
Odonata

Odonata is an order of predatory flying insects that includes the dragonflies and damselflies. The two groups are distinguished with dragonflies (suborder Epiprocta) usually being bulkier with large compound eyes together and wings spread up or out at rest, while damselflies (suborder Zygoptera) are usually more slender with eyes placed apart and wings folded together along body at rest. Adult odonates can land and perch, but rarely walk.

All odonates have aquatic larvae called naiads or nymphs, and all of them, larvae and adults, are carnivorous and are almost entirely insectivorous, although at the larval stage they will eat anything that they can overpower, including small fish, tadpoles, and even adult newts. The adults are superb aerial hunters and their legs are specialised for catching prey in flight.

Etymology and terminology
Johan Christian Fabricius coined the term Odonata in 1793 from the Ancient Greek ὀδών (Ionic form of ὀδούς ) "tooth". One hypothesis is that it was because their maxillae are notably toothed.

The word dragonfly usually denotes only Anisoptera, but is sometimes used to mean all Odonata. Odonata enthusiasts avoid ambiguity by using the term true dragonfly, or simply anisopteran, when they mean just the Anisoptera. An alternative term warriorfly has been proposed.

Size
The largest living odonate is the giant Central American helicopter damselfly Megaloprepus coerulatus (Zygoptera: Pseudostigmatidae) with a wing span of 191 mm. The heaviest living odonates are Tetracanthagyna plagiata (Anisoptera: Aeshnidae) with a wing span of 165 mm, and Petalura ingentissima (Anisoptera: Petaluridae) with a body length of 117 mm (some sources 125 mm) and wing span of 160 mm. The longest extant odonate is the Neotropical helicopter damselfly Mecistogaster linearis (Zygoptera: Pseudostigmatidae) with a body length of 135 mm.

The smallest living dragonfly is Nannophya pygmaea (Anisoptera: Libellulidae) from east Asia, with a body length of 15 mm and a wing span of 20 mm. The smallest damselflies (and also the smallest odonates) are species of the genus Agriocnemis (Zygoptera: Coenagrionidae) with a wing span of only 17–18 mm.

Description

These insects characteristically have large rounded heads covered mostly by well-developed, compound eyes, which provide good vision, legs that facilitate catching prey (other insects) in flight, two pairs of long, transparent wings that move independently, and elongated abdomens. They have three ocelli and short antennae. The mouthparts are on the underside of the head and include simple chewing mandibles in the adult.

Flight in the Odonata is direct, with flight muscles attaching directly to the wings; rather than indirect, with flight muscles attaching to the thorax, as is found in the Neoptera. This allows active control of the amplitude, frequency, angle of attack, camber and twist of each of the four wings entirely independently.

In most families, there is a structure on the leading edge near the tip of the wing called the pterostigma. This is a thickened, hemolymph–filled and often colorful area bounded by veins. The functions of the pterostigma are not fully known, but it most probably has an aerodynamic effect and may also have a visual function. More mass at the end of the wing may also reduce the energy needed to move the wings up and down. The right combination of wing stiffness and wing mass could reduce the energy consumption of flying. A pterostigma is also found among other insects, such as bees.

The nymphs have stockier, shorter, bodies than the adults. In addition to lacking wings, their eyes are smaller, their antennae longer, and their heads are less mobile than in the adult. Their mouthparts are modified, with the labium being adapted into a unique prehensile organ called a labial mask for grasping prey. Damselfly nymphs breathe through external gills on the abdomen, while dragonfly nymphs respire through an organ in their rectum.

Fossil history

Members of the crown group Odonata first appeared during the Late Triassic, though members of their total group, Odonatoptera, first appeared in the Late Carboniferous, making them one of the earliest groups of winged insects. The fossils of odonates and their cousins, including Paleozoic "giant dragonflies" like Meganeuropsis permiana from the Permian of North America, reached wing spans of up to 71 cm and a body length of 43 cm, making it the largest insect of all time. This insect belonged to the order Meganisoptera, the griffinflies, related to odonates but not part of the modern order Odonata in the restricted sense. They have one of the most complete fossil records going back 319 million years.

The Odonata is closely related to mayflies and several extinct orders in a group called the Palaeoptera, but this grouping might be paraphyletic. What they do share with mayflies is the nature of how the wings are articulated and held in rest.

Tarsophlebiidae is a prehistoric family of Odonatoptera that can be considered either a basal lineage of Odonata or their immediate sister taxon.

Phylogeny
The phylogenetic tree of the orders and suborders of odonates according to Bybee et al. 2021:

Taxonomy
In some treatments, the Odonata are understood in an expanded sense, essentially synonymous with the superorder Odonatoptera, but not including the prehistoric Protodonata. In this approach, instead of Odonatoptera, the term Odonatoidea is used. The systematics of the "Palaeoptera" are by no means resolved; what can be said however is that regardless of whether they are called "Odonatoidea" or "Odonatoptera", the Odonata and their extinct relatives do form a clade.

The Anisoptera was long treated as a suborder, with a third suborder, the Anisozygoptera (ancient dragonflies). However, the combined suborder Epiprocta (in which Anisoptera is an infraorder) was proposed when it was thought that the "Anisozygoptera" was paraphyletic, composed of mostly extinct offshoots of dragonfly evolution. The four living species placed in that group are (in this treatment) in the infraorder Epiophlebioptera, whereas the fossil taxa that were formerly there are now dispersed about the Odonatoptera (or Odonata sensu lato). World Odonata List considers Anisoptera as a suborder along with Zygoptera and Anisozygoptera as well-understood and widely preferred terms.

Ecology and life cycle

Odonates are aquatic or semi-aquatic as juveniles. Thus, adults are most often seen near bodies of water and are frequently described as aquatic insects. However, many species range far from water. They are carnivorous (or more specifically insectivorous) throughout their life, mostly feeding on smaller insects.

Male Odonata have complex genitalia, different from those found in other insects. These include grasping cerci at the tip of the abdomen for holding the female, and a secondary set of copulatory organs located between the second and third abdominal segment in which the spermatozoa are stored after being produced by the primary genitals— whose external opening is known as the genital pore, on the ninth abdominal segment. This process is called intra-male sperm translocation (ST). Because the male copulatory organ has evolved independently from that in other insects, it has been suggested the stem-group dragonflies had external sperm transfer. To mate, the male claspers grasps the female by the thorax (Zygoptera) or head (Anisoptera) while the female bends her abdomen so that her own genitalia can be grasped by the copulatory organ holding the sperm. This is known as the "wheel" position.

Eggs are laid in water or on vegetation near water or wet places, and hatch to produce pronymphs which live off the nutrients that were in the egg. They then develop into instars with approximately 9–14 molts that are (in most species) voracious predators on other aquatic organisms, including small fishes. The nymphs grow and molt, usually in dusk or dawn, into the flying teneral immature adults, whose color is not yet developed. These transform into reproductive adults.

Odonates can act as bioindicators of water quality in rivers because they rely on high quality water for proper development in early life. Since their diet consists entirely of insects, odonate density is directly proportional to the population of prey, and their abundance indicates the abundance of prey in the examined ecosystem. Species richness of vascular plants has also been positively correlated with the species richness of dragonflies in a given habitat. This means that in a location such as a lake, if one finds a wide variety of odonates, then a similarly wide variety of plants should also be present. This correlation is not common to all bioindicators, as some may act as indicators for a different environmental factor, such as the pool frog acting as a bioindicator of water quality due to its high quantity of time spent in and around water.

In addition, odonates are very sensitive to changes to average temperature. Many species have moved to higher elevations and latitudes as global temperature rises and habitats dry out. Changes to the life cycle have been recorded with increased development of the instar stages and smaller adult body size as the average temperature increases. As the territory of many species starts to overlap, the rate hybridization of species that normally do not come in contact is increasing. If global climate change continues many members of Odonata will start to disappear. Because odonates are such an old order and have such a complete fossil record they are an ideal species to study insect evolution and adaptation. For example, they are one of the first insects to develop flight and it is likely that this trait only evolved once in insects, looking at how flight works in odonates, the rest of flight can be mapped out.

title: Odonata


text:
Talk:Fermion

bose einstein condensate
So a grain of sand prevents another grain of sand from occupying the same location.

Unless it's cold enough to form a bose einstein condensate!

BECs are formed out of bosons! Hence "bose." However, fermions can form condensates -- but they are condensates in momentum space only, not physical space. (i.e., the condensate has lots of fermions with the same momentum, but they are not all in the same place), so the Pauli ex. principle is not violated.

 * Can you explain this or point to a reference? As far as I'm aware, there's no difference in this respect between position space and momentum space -- antisymmetry in both cases requires the wavefunction to vanish at equal position/equal momentum. Fpahl 06:15, 8 Oct 2004 (UTC)

Pauli exclusion principle
The Pauli exclusion principle doesn't always work, according to my quantum textbook. See my discussion in talk:Pauli exclusion principle. -- Tim Starling

 * The result of that discussion was that the textbook meant not that it doesn't always work, but that in some circumstances it's a safe approximation to ignore it in calculations. Tim agreed, so I guess the comment above is just a leftover. Fpahl 06:15, 8 Oct 2004 (UTC)

PEP works all the time for all the massive fermions in a bound state (I haven't heard about massless half-integer spin particles, as neutrinos are considered in Standard Model of Elementary Particle, to form a bound state). serbanut —Preceding signed but undated comment was added at 07:39, 15 September 2007 (UTC)

Definition of Fermions as particles requiring antisymmetric states
In the first line it is stated, and in the definition it is repeated, that fermions obey Fermi-Dirac statistics by definition. What is meant here is perhaps Fermi-Dirac statistics which to my knowledge codes for anticommutation relations for second quantized operators, thus antisymmetric wavefunctions. This is something different from the momentum distribution referred to by Fermi-Dirac statistics / distribution of many free fermions. I propose to change fermi-dirac into fermi in the two indicated places because it spreads confusion to those not familiar with the subject.

The subtlety is purely semantic, because clearly interacting electrons aren't in general described by fermi-dirac statistics. For instance, the fermi-liquid isn't merely described by a stepfunction in momentum space at zero temperature. —Preceding unsigned comment added by Danielabel (talk • contribs) 14:39, 16 September 2009 (UTC)

I'm wondering whether the article's definition of fermions as particles requiring antisymmetric states is the best approach. According to the spin-statistics theorem, this is equivalent with having half-integer spin. But if a particle were found to violate that theorem, say a particle with integer spin and antisymmetric wavefunction (I'm aware that it's not clear how this could be and it would probably require a major change in quantum field theory), would we say "we found a fermion whose spin isn't half-integer", or would we say "we found a boson whose state isn't symmetric"? I think the latter, which would imply that the definition of a fermion is a particle with half-integer spin. This is also how Eric Weisstein's World of Physics defines it. (The same applies, obviously, to bosons; I added a link to this discussion on their talk page.) Fpahl 06:15, 8 Oct 2004 (UTC)
 * I disagree with you. For me, a fermion is an anticommuting operator (in "second quantization" formalism) and an expression like "spinless fermion" is not self-contradictory. _R_ 14:54, 8 Oct 2004 (UTC)
 * You're right. A survey of my QFT textbooks yielded overwhelming evidence for this view, with two books explicitly stating the spin-statistics theorem as saying that fermions have half-integer spin, not that they anticommute. I could be forgiven, though, since Kaku in "Quantum Field Theory: A Modern Introduction", one of the standard texts, writes: "To demonstrate the spin-statistics theorem, let us quantize bosons with anticommutators and arrive at a contradiction. ... Likewise, one can prove that fermions quantized with commutators violates microcausality." This only makes sense if "fermions" is taken to mean "particles with half-integer spin".
 * Do I understand correctly that in the above admittedly unlikely scenario you would be inclined to say "we found a fermion whose spin isn't half-integer"? Fpahl 15:24, 8 Oct 2004 (UTC)

 * I would disagree with anticommutation rules - they do not always define fermions. What you say is true if you consider non-interacting systems. If you take bosons on a loop interacting via Dirac-delta potential, then 1) they have ,,Fermion'' comutation rules (they cannot occupy the same quantum state because of interaction) 2) they have still symmetric wave function.

 * Interestingly, our own article on the spin-statistics theorem takes the other view. Would you agree it should be changed accordingly? Fpahl 15:28, 8 Oct 2004 (UTC)

 * A new twist to the story: I emailed mathworld about this since your view suggests that their definitions are wrong, and they sent me this:

The Particle Data Group controls these definitions. Here are the definitions from Particle Data Group: Fermion: Any particle that has odd-half-integer (1/2, 3/2, ...) intrinsic angular momentum (spin), measured in units of h-bar. All particles are either fermions or bosons. Fermions obey a rule called the Pauli Exclusion Principle, which states that no two fermions can exist in the same state at the same time. Many of the properties of ordinary matter arise because of this rule. Electrons, protons, and neutrons are all fermions, as are all the fundamental matter particles, both quarks and leptons. Boson: A particle that has integer intrinsic angular momentum (spin) measured in units of h-bar (spin =0, 1, 2, ...). All particles are either fermions or bosons. The particles associated with all the fundamental interactions (forces) and composite particles with even numbers of fermion constituents (quarks) are bosons.

 * Has the Particle Data Group got it wrong?! Fpahl 17:07, 8 Oct 2004 (UTC)

 * I would argue that the PDG is primarily concerned with particle phenomenology, and thus intends their definition to discriminate solely between existing particles (for which the distinction between the definitions in question is moot). In QFT, it's certainly the case that when we say "fermion" we mean "fields represented by anticommuting Grassman numbers". If we want to talk about a particle that happens to have spin-1/2 but commutes, we'd call it a "pseudofermion". So one might argue that both characteristics are necessary for a particle to be a fermion, and thus that there are really four classes of particle: fermion, boson, pseudofermion and pseudoboson; only two of which actually exist. -- Xerxes 18:53, 2004 Oct 8 (UTC)

 * (Note: I wrote the following before seeing Xerxes' answer) Of course, it's got it wrong! What else do you expect from particle physicists? Seriously though, the flaw in this definition is the following: how do you count the number of fermion constituents in a phonon?
 * The more I think of it, the more I believe it depends on whether you focus on individual particles (in which case fermion=half-integer spin) or on their collective behaviour (in which case fermion=anticommuting operator=antisymmetric wavefunction). _R_ 19:05, 8 Oct 2004 (UTC)

Fermions with odd integer spin
We have all noticed that spin is described as being a multiple of hbar/2. I thought that it would be better to set this value to a constant giving,

hdot = hbar/2 = 5.2728584118222738157569629987554e-35 J.s

But now the equations for spin did not work with hdot, so I had to correct them.

Here are the corrected equations,

 * sv| = sqrt(s(s + 2)) * hdot

and

Sz = ms.hdot

where,

sv is the quantized spin vector,

 * sv| is the norm of the spin vector,

s is the spin quantum number, which can be any non negative integer,

Sz is the spin z projection,

ms is the secondary spin quantum number, ranging from -s to +s in steps of two integers

For spin 1 particles this gives:

 * sv| = sqrt(3).hdot and Sz = -hdot, +hdot

For spin 2 particles this gives:

 * sv| = sqrt(8).hdot and Sz = -hdot, 0, +hdot

Now that the spin equations have been corrected, the definitions for fermions and bosons are incorrect, and must be redefined as follows.

Fermions are particles that that have an odd integer spin.

Bosons are particles that have an even integer spin.

Would these redefinitions have any other effects on the Standard Model? Can these redefinitions explain any currently unexplained phenomena? Are there any experiments that could confirm or refute these claims?

I would like eveyone to have a good think about this, and give me your objections to it, or even data to support it.

 * The change you're proposing is a trivial renormalization; physicists are perfectly happy with the convention as it stands, tho mathematicians studying lie groups tend to use a normalization with steps of two. -- Xerxes 17:47, 2005 Jun 8 (UTC)

 * Actually, the above explanation is no different than the Standard Model except in notation. In spin-statistics theorem, the only difference is the word "net" where fermions have a "net" energy rotation spin and bosons are particles where the "net" energy rotation cancels in the composite matter structures.  The notation of the Standard Model was developed through the evolution of theory.  Bosons were discovered first so assigned integer values beginning with 1 as is the common mathematical convention.  Had fermions been discovered first, then fermions would have been denoted 1 and no doubt, bosons, would have taken even numbers to show that the net spin effect cancels.  Scientific and mathematical notation often simply follows the legacy of the evolving discoveries i.e. s,p,d for azimuthal quantum numbers makes no real sense except it is legacy notation.--Voyajer 19:56, 21 December 2005 (UTC)

Bosonic field and Fermionic field articles
We need some help defining just what a bosonic field is, and what a fermionic field is. Please see the discussion pages for Bosonic field and Fermionic field. Thanks. RK 19:56, 21 May 2006 (UTC)

Elementary particles??
I am an ignorant of physics, so I do not understand these two sentences in the article, which look contradictory to me: "[fermions] are sometimes said to be the constituents of matter."

"All observed elementary particles are either fermions or bosons."

The first sentence seems to exclude bosons, and it is stated the same in other articles in Wikipedia ("quark", for example). Will anybody be so kind to explain? Thanks 200.55.118.233 23:42, 31 August 2006 (UTC) Nahuel

There are two groups of particles in elementary particle physics:

1. elementary particles described by non-interacting fields;

2. interaction carriers describing the interacting fields.

The first category contains fermions, and the second contains bosons. For example, electrons, muons, taons, neutrinos, quarks are fermions (spin one half) and they are considered elementary particles, and photons, Z0, W+/-, gluons are interaction carriers and they are bosons. serbanut —Preceding signed but undated comment was added at 07:48, 15 September 2007 (UTC)

This is the dilemma of Wikipedia: that reasonable questions about clarity and accuracy can persist for years without being resolved. This is an encyclopedia and the "non-expert" can be expected to be the "primary customer", not a particle physicist. I find the following ambiguity in 2012: in the introduction there is the statement: " Fermions are usually associated with matter, whereas bosons are generally force carrier particles; although in the current state of particle physics the distinction between the two concepts is unclear." I think that the distinction is much more clear than than the reader is led to believe. Moreover, the deuteron (spin =1), which is a boson, is as much a particle of matter as the proton (spin=1/2), a fermion. So the statement that "bosons are generally force carrier particles can hardly be correct. I suspect that the author meant to say that force carrier particles are generally (always?) bosons.  In other words, this appears to me to be lax English (I hope!).  In any case, a clarification by a knowledgable expert is over due: you can help save Wikipedia from scientific perdition.  Tachyon 13:09, 8 October 2012 (UTC)  — Preceding unsigned comment added by Janopus (talk • contribs)

 * The statement that "fermions are usually associated with matter, whereas bosons are generally force carrier particles", which, following the discussion presented in this section, appears to have been present in the article since at least 2007 (!), cannot reasonably be said to be theoretically correct in current form. As the recent poster mentions, the deuteron -- as well as any meson, electronic cooper-pair, hydrogen molecule, helium-4 atom, or water molecule, among many, many, 'many' others falling clearly under any intuitive concept of the theoretically ill-defined term "matter" -- is also a bosonic system.  There are two possible "fixes" for the issue; the first, which surely better represents the author's original intentions but is in my opinion the worse fix, would be to add the qualifier "elementary" in front of "fermions" and "bosons", making clear that the author is not referring to composite particular systems.  However, since the proton and the neutron, which are 'not' elementary particles (as the article correctly indicates), are given in the article as "key building blocks of matter", further confusion may ensue.  The better fix, in my opinion, would be to remove the statement entirely (as well as the similar associated statement from the Boson article), as "matter" in any case is not a term that has a robust theoretical definition in the Standard Model.  I suppose some combination of the two, perhaps adding both the "elementary" qualifier and some disclaimer emphasising that "matter" is not a theoretically robust term in particle physics, might even be best in an article aimed generally at the layperson.  At any rate, given the unfortunate behaviour of many Wikipedia science-section editors, I won't attempt to make any change myself, but since lay visitors have presumably been confused by the unfortunate wording in the article for some five years now, I suspect it would serve the article well to finally address the issue.70.113.16.249 (talk) 06:23, 15 October 2012 (UTC)

Please Explain
The paragraph begining "Of course..." is not helpfull to the uninitiated (I speak as someone visiting the page without a prior background in the subject matter). If there is a more appropriate topic on why "determining the fermionic or bosonic behavior of a composite particle (or system) is only seen at large (compared to size of the system) distance", perhaps there should be a link to it.

Confusing paragraph
The article has the following paragraph:

All observed elementary particles are either fermions or bosons. A composite particle (made up of more fundamental particles) may either be a fermion or a boson, depending only on the number of fermions it contains:
 * Composite particles containing an even number of fermions are bosons, such as a meson, or the nucleus of a carbon-12 atom.
 * Composite particles containing odd number of fermions are fermions, such as a baryon, or the nucleus of a carbon-13 atom.

I could not understand how an even number of fermions are bosons, while all elementary particles are either fermions or bosons. Also I could not understand how the fermions have only odd number of fermions. It doesn't make sense.

I guess it could be poor choice of words. Otherwise please explain further about how these particles behave. —The preceding unsigned comment was added by Tenri (talk • contribs) 04:10, 10 March 2007 (UTC).

I think the wording is confusing--fermion simply describes any particle with half integer spin so it can describe both elementary as well as composite particles. Primary fermions are quark and leptons. 3 quarks together is a baryon which is a composite fermion (because it has half spin). 2 quarks together makes a meson (having integer spin). I will edit the text to try to clarify. Can someone please double check and see if it makes sense? ThanksTensegrity 23:45, 2 April 2007 (UTC) Ah, thank you for correcting my brain fart re: the atomic weight/nbr of nucleons. :) Tensegrity 18:10, 4 April 2007 (UTC)

New image
Please comment of the new table of elementary particles at Graphic_Lab/Images_to_improve. Thanks. Dhatfield (talk) 22:51, 28 June 2008 (UTC)

Experimental fact
Don't you think it is necesary for non physicist to know some fundamental experimental facts to explain why it is postulated the existence of fermions? Paranoidhuman (talk) 00:44, 18 August 2008 (UTC)

Right-handed fermions
Chirality (physics) says there are some left-handed fermions (the ones that feel the weak nuclear force) implying there are right-handed ones that don't. Should this article on fermions mention chirality or refer somewhere ? Weak interaction has a table of left-handed fermions (and implies their antiparticles are right-handed and feel the weak interaction). Standard_Model seems to say W and Z behave differently regarding L/R-handedness. Are there any right-handed fermions (as opposed to antifermions) ? - Rod57 (talk) 17:57 26 November 2012 (UTC)

 * Yes, there are plenty of right handed fermions - except for the neutrino, which only feels the weak force.-- cheers, Michael C. Price talk 20:43, 26 November 2012 (UTC)

Elementary fermions
When the text says a Dirac (massive) fermion can be treated as a "combination" of two Weyl (massless) fermions, the word combination must mean something other than a composite particle, which if it were made of two fermions would be a boson. I suspect it means superposition. If so it would be good say superoposition and for some knowledgeable person to add, or point to, a simple explanation of how a superposition of two massless particles can have mass.CharlesHBennett (talk) 13:54, 15 May 2013 (UTC)

Nothing in Wikipedia on Weyl fermions?
Wikipedia has articles on Dirac fermions and Majorana fermions but nothing at all on Weyl fermions beyond the parenthetical "massless" in this article and a mysterious link to Spinors whose only mention of any kind of fermion is in the phrase "electrons and other fermions". The article on Fermionic fields refers to Weyl spinors without however saying what they are. Moreover Wikipedia lists 38 topics named after Hermann Weyl with no mention of Weyl fermions. Yet a web search for "Weyl fermion" turns up 9,740 results. Why this omission? --Vaughan Pratt (talk) 17:53, 9 October 2013 (UTC)

All fermions obey Fermi Dirac statistics - true or false? (definition question)
At the moment the first sentence of the article says "In particle physics, a fermion [...] is any particle characterized by Fermi–Dirac statistics and [...]". I'd like to ask a question about definitions here, as I'm fairly sure that this sentence is wrong and misleading.

As far as I understand, when people say "Fermi Dirac statistics" they have in mind a result from statistical thermodynamics of non-interacting fermions in thermal equilibrium. This very specific and idealized result is associated with the Fermi occupation number $$\scriptstyle N_i = [1 + \exp(\tfrac{E_i-\mu}{kT})]^{-1}$$. If this is the intended meaning of Fermi-Dirac statistics, then I'd like to point out that typically, fermions do not obey Fermi Dirac statistics: fermions that we can get into equilibrium generally have significant interactions (e.g. electrons); fermions with weak interactions are usually not in equilibrium (e.g. neutrinos). Fermi Dirac statistics are often a good approximation for electrons in metals / semiconductors, but by no means are they exact and violations are often found.

On the other hand, if "Fermi Dirac statistics" is intended to refer to the general quantum mechanical principles of Pauli exclusion / exchange antisymmetry / etc., then indeed all fermions follow Fermi Dirac statistics. However, if that is so, then the article Fermi–Dirac statistics needs to be massively reworked for this more general meaning.

The question is, which is the generally recognized meaning of "Fermi Dirac statistics"? Nanite (talk) 18:30, 30 January 2014 (UTC)

Assessment comment
Substituted at 15:05, 29 April 2016 (UTC)

Is the first sentence contradictory with the spin-1/2 article?
The first sentence "In particle physics, a fermion is a particle that follows Fermi–Dirac statistics and generally has half odd integer spin: spin 1/2, spin 3/2, etc" bears a warning that reads "contradicts material at the article 'Spin-1/2'." I personally don't see where the contradiction is. It if refers to the fact than the Spin-1/2 article reads "All known fermions, (…) have a spin of ½," there is actually no contradiction.

Spin 3/2 and 5/2
What is the difference between a spin-1/2 and spin 3/2 and spin 5/2 fermion, and are there any known fermions with 3/2 or 5/2 or higher? I just redirected Spin 3/2 and Spin 5/2 here because Spin (physics) only has math which is meaningless to most readers. -- Beland (talk) 07:44, 11 September 2021 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Fermion


text:
Constrained writing

Constrained writing is a literary technique in which the writer is bound by some condition that forbids certain things or imposes a pattern.

Constraints are very common in poetry, which often requires the writer to use a particular verse form.

Description
Constraints on writing are common and can serve a variety of purposes. For example, a text may place restrictions on its vocabulary, e.g. Basic English, copula-free text, defining vocabulary for dictionaries, and other limited vocabularies for teaching English as a second language or to children.

In poetry, formal constraints abound in both mainstream and experimental work. Familiar elements of poetry like rhyme and meter are often applied as constraints. Well-established verse forms like the sonnet, sestina, villanelle, limerick, and haiku are variously constrained by meter, rhyme, repetition, length, and other characteristics.

Outside of established traditions, particularly in the avant-garde, writers have produced a variety of work under more severe constraints; this is often what the term "constrained writing" is specifically applied to. For example:

 * Reverse-lipograms: each word must contain a particular letter.
 * Univocalic poetry, using only one vowel.
 * Mandated vocabulary, where the writer must include specific words (for example, Quadrivial Quandary solicits individual sentences containing all four words in a daily selection).
 * Bilingual homophonous poetry, where the poem makes sense in two different languages at the same time, constituting two simultaneous homophonous poems.
 * Alliteratives or tautograms, in which every word must start with the same letter (or subset of letters; see Alphabetical Africa).
 * Lipogram: a letter (commonly e or o) is outlawed.
 * Acrostics: first letter of each word/sentence/paragraph forms a word or sentence.
 * Abecedarius: first letter of each word/verse/section goes through the alphabet.
 * Palindromes, such as the word "radar", read the same forwards and backwards.
 * Anglish, favouring Anglo-Saxon words over Greek and Roman/Latin words.
 * Pilish, where the lengths of consecutive words match the digits of the number π.
 * Anagrams, words or sentences formed by rearranging the letters of another.
 * Limitations in punctuation, such as Peter Carey's book True History of the Kelly Gang, which features no commas.
 * One-syllable article, a form unique to Chinese literature, using many characters all of which are homophones; the result looks sensible as writing but is very confusing when read aloud.
 * Chaterism, where the length of words in a phrase or sentence increases or decreases in a uniform, mathematical way.
 * Aleatory, where the reader supplies a random input.
 * Erasure, which involves erasing words from an existing text and framing the result on the page as a poem.

The Oulipo group is a gathering of writers who use such techniques. The Outrapo group uses theatrical constraints.

There are a number of constrained writing forms that are restricted by length, including:
 * Six-Word Memoirs: 6 words
 * Haiku: ~ 3 lines (5–7–5 syllables or 2–3–2 beats recommended.)
 * Minisaga: 50 words, +15 for title
 * Drabble: 100 words
 * Twiction: espoused as a specifically constrained form of microfiction where a story or poem is exactly 140 characters long.
 * Sijo: three lines average 14–16 syllables, for a total of 44–46: theme (3, 4,4,4); elaboration (3,4,4,4); counter-theme (3,5) and completion (4,3).

Examples

 * Ernest Vincent Wright's Gadsby (1939) is an English-language novel consisting of 50,000 words, none of which contain the letter "e".
 * In 1969, French writer Georges Perec published La Disparition, a novel that did not include the letter "e". It was translated into English in 1995 by Gilbert Adair. Perec subsequently joked that he incorporated the "e"s not used into La Disparition in the novella Les Revenentes (1972), which uses no vowels other than "e". Les Revenentes was translated into English by Ian Monk as The Exeter Text: Jewels, Secrets, Sex.
 * Perec also wrote Life A User's Manual using the Knight's Tour method of construction. The book is set in a fictional Parisian block of flats, where Perec devises the elevation of the building as a 10×10 grid: 10 storeys, including basements and attics and 10 rooms across, including 2 for the stairwell. Each room is assigned to a chapter, and the order of the chapters is given by the knight's moves on the grid.
 * Several of the Psalms are abecedarian in the Hebrew alphabet.
 * The 2004 French novel Le Train de Nulle Part (The Train from Nowhere) by Michel Thaler was written entirely without verbs.
 * let me tell you (2008), a novel by the Welsh writer Paul Griffiths, uses only the words allotted to Ophelia in Hamlet.
 * Experimental Canadian poet Christian Bök's Eunoia is a univocalic that uses only one vowel in each of its five chapters.
 * One famous piece of constrained writing in the Chinese language is "Lion-Eating Poet in the Stone Den", which consists of 92 characters, all with the sound shi. Another is the Thousand Character Classic in which all 1000 characters are unique without any repetition.
 * "Cadaeic Cadenza" is a short story by Mike Keith using the first 3835 digits of pi to determine the length of words. Not A Wake is a book using the same constraint based on the first 10,000 digits.
 * Never Again is a novel by Doug Nufer in which no word is used more than once.
 * Ella Minnow Pea is a book by Mark Dunn where certain letters become unusable throughout the novel.
 * Alphabetical Africa is a book by Walter Abish in which the first chapter only uses words that begin with the letter "a", while the second chapter incorporates the letter "b", and then "c", etc. Once the alphabet is finished, Abish takes letters away, one at a time, until the last chapter, leaving only words that begin with the letter "a".
 * Mary Godolphin wrote versions of Robinson Crusoe, Aesop's Fables, The Swiss Family Robinson, and other books using only monosyllabic words.
 * Theodor Geisel, also known as Dr. Seuss, wrote the well-known children's book Green Eggs and Ham using only 50 different words on a 50 dollar bet with Bennett Cerf.
 * The Gates of Paradise is a book by Jerzy Andrzejewski where the whole text is just two sentences, one of which is very long.
 * Zero Degree is a postmodern lipogrammatic novel written in 1998 by Tamil author Charu Nivedita, later translated into Malayalam and English. The Tamil words "oru" and "ondru" (the English equivalents are "a", "an" and "one") have not been mentioned anywhere in the novel, except one chapter. Keeping with the numerological theme of Zero Degree, the only numbers expressed in either words or symbols are numerologically equivalent to nine (with the exception of two chapters). This Oulipian ban includes the very common word one. Many sections of the book are written entirely without punctuation, or using only periods.
 * In the book A Gun Is Not Polite, author Jonathan Ruffian rearranges given sentences containing the word "gun" as found on the internet into microfiction.
 * Uruguayan musician, comedian and writer Leo Maslíah's 1999 novel Líneas (Lines) is written entirely with paragraphs comprising a single sentence.
 * A novel Gorm, Son of Hardecnut (Горм, сын Хёрдакнута) (see Gorm the Old) by Peter Vorobieff is written in Russian without any words borrowed from English, French, Latin, or modern German since the 17th century (similar to Anglish). The book also never uses many common words, including "human", "please", and "thank you".
 * Examples of erasure include Tom Phillips's A Humument (1970); Mary Ruefle's A Little White Shadow (2006), an erasure of the Victorian novel of the same name by Emily Malbone Morgan; Janet Holmes's The ms of my kin (2009), an erasure of poetry by Emily Dickinson; Matthea Harvey's Of Lamb (2011), an erasure of a biography of Charles Lamb; ALL KINDS OF FUR, Margaret Yocom's erasure of a controversial tale from the Brothers Grimm (2018); and many more.
 * Anna Rabinowitz's Darkling (2001) is a book-length acrostic about the Holocaust.
 * The 17th-century Odia poet Upendra Bhanja wrote multiple epics (Satisha Bilasa, Kala Kautuka, Baidehisha Bilasha, etc.) with the same syllable at the beginning of each sentence.
 * "Weird Al" Yankovic's song "Bob" has lyrics consisting entirely of palindromes.
 * Brian Raiter, a computer programmer, wrote a more than 4,000-word article explaining Albert Einstein's theory of relativity using only words of four letters or less.
 * Grant Maierhofer's Ebb, a novel, was written entirely without the letter A, and published in 2023 by Kernpunkt Press. "It concerns a community of artists and others, engaging in their lives and figuring things out. A Oulipian experiment wherein things fall apart."

Comics
Notable examples of constrained comics:
 * Gustave Verbeek's The Upside Downs of Little Lady Lovekins and Old Man Muffaroo, a weekly 6-panel comic strip in which the first half of the story was illustrated and captioned right-side-up, then the reader would turn the page up-side-down, and the inverted illustrations with additional captions describing the scenes told the second half of the story, for a total of 12 panels.
 * The Angriest Dog in the World a comic strip by David Lynch. Each four-panel comic has identical artwork. The only change between each comic is the dialogue in the first three panels.
 * Dinosaur Comics which uses the same artwork, with only dialogue changing.
 * Watchmen is created with a number of formal constraints; issue #5 in particular, entitled "Fearful Symmetry", follows a palindromic structure.
 * Partially Clips which uses three identical panels based on clipart.
 * The many works of the Oubapo group.
 * Matt Madden's 99 Ways to Tell a Story.

title: Constrained writing


text:
Talk:Tracey Ullman

Occupation of Father
Was he a lawyer, solicitor, businessman or a salesman?

Remember "solicitor" in the UK is an attorney: in the USA it is (mainly) a salesman.

I doubt it...
"At age 12, a headmaster saw Ullman's future potential, and recommended her to the Italia Conti Academy" I very much doubt this. The head teacher may have apporved the move, but head teachers don't spot talent, teachers do. DId the head teacher happen to walk along the corridor and spot what the music teacher and drama teacher had missed? More likelt, the head allowed something to happen. —Preceding unsigned comment added by Paulmarkj (talk • contribs) 00:41, 29 November 2009 (UTC)

2002 discussions
My secret plot to get enough material to make a Stiff records article has succeeded! "A label with punk attitude and eclectic tastes". Data below. Ortolan88

From the article:
 * In 1984, she had great success as a singer on the legendary punk label Stiff records, where she had six songs on the British Top 100 in less than two years, including her first hit "You Broke My Heart in 17 Places", and the international hit "They Don't Know".

This was not punk. Her songs were over-the-top evocations of 60s and 70s pop music with an 80s edge, "somewhere between Minnie Mouse and the Supremes" as England's Melody Maker put it, or "retro before retro was cool", according to a retrospective review. --Ortolan88

I'm not following the plot here. You say in your Summary line: "[meta comments moved to talk -- be bold Ortolan88 and edit-out the "punk" statement and include your own thoughts]".

I don't see anything wrong here, and certainly no cause for deletion. These aren't my opinions at all and I don't think they should be. What is there to be bold about?

It is news, if you will, that "Our Trace" recorded on Stiff, but having said that, it had to be made clear that she wasn't a punk artist as virtually every other Stiff star was.
 * Nonsense. Madness weren't punk (too ska), Ian Dury wasn't punk (too music hall), Elvis Costello wasn't either, though he was sometimes marketed as such.  Stiff were, as their slogan at the time stated, The World's Most Flexible Record Label -- User:GWO

I never heard that slogan. All I heard were "We came. We saw. We left." and "If it ain't Stiff it ain't worth a f*ck." So, okay, Madness wan't punk. Elvis Costello was "a punk" even if his music wasn't officially '"punk". I have here before me two Stiff compilations, and great record albums ("Live Stiffs"
 * A record that contains a straight and sincere reading of "I Just Don't Know What To Do With Myself" by punk icon Burt Bacharach :)

and "Hits Greatest Stiffs"), and who do I see but Wreckless Eric, Larry Wallis,
 * Pub rockers, to a man...

Pink Fairies, Tyla Gang, Motörhead (the Larry version), The Damned, Richard Hell. How could you ever get the idea that Stiff was a punk label? So Nick Lowe is a pop star, but he wrote a song about a dog devouring the corpse of a hasbeen movie queen and Ian Dury was "music hall", but he wrote "Sex and Drugs and Rock and Roll" and "Hit Me with your Rhythm Stick"
 * ''Play either of those records to someone who didn't know Dury, and I bet you dollars to donuts the thought "Punk Rock" wouldn't cross their minds.

Play Ian Dury for someone who'd never heard him and they'd say "I never heard anything remotely like this in my whole life. Ortolan88

Also, the late, lamented Kirsty McColl was on Stiff, and she wasn't a punk either. Stiff had some punks (Damned, Hell) but they weren't close to a majority, let alone "almost all"'' -- User:GWO and "Our Trace" was a reincarnation of Leslie Gore crossed with John Entwistle, but their record label was awash with punks and it had a punk attitude. I suppose you'd call Lew Lewis a blues singer, but I'd call him a Stiff star. If I wrote about Madness, I'd probably feel obliged to make the same point I did about Tracey, a non-punk on a punk label. Best regards, music fans, Ortolan88

I thought I should characterize the music accurately, which I did, after listening to "They Don't Know". Not punk, but retro with attitude. That is a description, not an opinion.

Both the Melody Maker and the "retro" quote came from the semi-official "Go Home" site, but it would have been too complicated and wordy to give it a clear and correct credit so I made it anonymous. But it wasn't me.

I will listen to what you have to say before restoring this innocuous and informative material to the article. If the wording is confusing, please let me know, but gee, my heart is pure here. Ortolan88

 * The wording is confusing - it appeared to be an inserted comment which was trying to refute the above statement and not simply the opposing ideas of another group. Please do put the removed sentences back in. However, please do modify "This wasn't punk." to something like; "Others contend that her work can not in fact be considered to be punk, because....". Hope this helps. --maveric149

Okay, cool. rewrote it. tried to make short sentence do too much work. I think I'll delete this talk unless you think it has historical value.

--- Ortolan88, i changed the article because i felt that DOB should just be (December 30, 1959 -) and not include where someone was born in that part of the article. i have done this with others and no one has objected before. may i ask what your objection is? --Anon
 * I think it was less of an objection and more of a matter of style -- I voted for your way of doing things Anon by changing the article and I hope that Ortolan88 agrees with the change (the current format is the "standardish" way of doing things around here). --maveric149

-- Thank you Maveric - it is just my feeling that full birth (and death) dates (e.g. July 7, 1919 - May 20, 1996) for Jon Pertwee) is the best style for articles on people. -- Paul Melville Austin (Anon)

Change that stuff around as you like. I really don't think there's enough material available on wiki style. It's all folklore tucked away in user pages and summary lines: I just learned that movie titles are italicized, but if it is documented elsewhere than in italicized movie titles, I haven't found it. Ortolan88

---

Is there a guideline page on how to give birth & death dates & places? If there isn't maybe some of the discussion here could be cooked up to start one. (and placenames too... "London, England" just looks wrong) -- user:Tarquin

Tracey's first UK hit was "Breakaway" (which also became a minor hit in the US). "You Broke My Heart In 17 Places" is actually the title track to her first album and was not issued as a single. -- RMc

Guideline for Dates
See Manual of Style (dates and numbers) for the guideline on birthdates. Please do not change the date format in this article unless you have a really good reason that trumps this clear guideline. --Vbd 14:43, 5 February 2007 (UTC)
 * For a person still living at the time the article was written, the example given is: Serena Williams (born September 26, 1981).

Citations/Footnotes Missing
This article is in serious need of citations or footnotes. It is entirely unsourced. I had also previously tagged this with a "Fan Site" warning because of its informal, un-encyclopedic tone and content. I do not have the time right now to start trying to find sources for the article. I am hoping that whoever has contributed to its development in the past will go back and add appropriate citations.--Vbd 16:35, 5 February 2007 (UTC)

One area that this article has gotten at least some of it's information is from Ullman's autobiographical stage show, "Live and Exposed". Do you know how to add a footnote, or at least somehow show how to source the content? That would at least take care of the early years section. I'll look into cleaning some of the page up as it has the necessary information, albeit it, messy, and add adequate sourcing. If you could help with finding out how to source a stage show that is on DVD, and how to basically source it in the article, it would be most helpful. Thanks!

 * Update: I have ten sources to add.  Will be up soon. —The preceding unsigned comment was added by 68.82.82.248 (talk) 05:34, 14 March 2007 (UTC).

Lawsuit against The Simpsons
It doesn't say if she won or lost the law suit. Please add it in there. 65.40.239.99 07:11, 11 February 2007 (UTC)
 * The article says: "A settlement was reached whereby Ullman would receive a portion of the profits made from the show, although no amount was ever publicly disclosed." However, in the article for The Simpsons shorts, it says the judge ruled in favor of the Network, which one is correct?Vicco Lizcano (talk) 18:36, 14 May 2008 (UTC) (Hey! Listen!)

Gender Blur
The inability to distinguish between comedians and comediennes is rather inarticulate. Is there a Wikimandate that requires gender blur or would it be permissible to acknowledge that she is in fact female?

(wkdugf3649.0974hd)
 * I think that her gender is apparent from the dozens of sentences in the article that refer to her by pronouns such as "she" or "her", including every sentence in the opening section. Oh, and the photograph too. --Metropolitan90 (talk) 08:27, 27 December 2007 (UTC)

Controversy over outside links
May I comment on the recent controversy and possible edit war over the inclusion of links to outside sites, notably three sites that unofficially cover Tracey's career? I must tread lightly here because I am the owner of one of those sites. In the past, I have generally refrained from editing this page because my site was linked here. If it wasn't linked here as a main External Link, I would feel more free to contribute. Indeed, my most recent edit (when Tracey became a US citizen) was made during a time when my site wasn't linked.

Maddyfan, I appreciate what you're trying to do, but I think it's becoming counterproductive. Please stop, for I would be better able to improve the page if my site is not linked.

Now it may be that some of my future edits might be cited by a link to a page on my site (example: a discography). That probably should be discussed on the talk page beforehand. Rreini 18:47, 22 September 2007 (UTC)

List of Recurring Characters
The article would benefit from either a list or a description of some of Ms. Ullman's recurring characters appearing on The Tracey Ullman Show on Fox television. Some of them were both famed and beloved. 71.178.118.11 09:43, 7 October 2007 (UTC)kenneth_bloomer

Good suggestion, although it might be better suited for the article on the show. I have created such a list (available at http://www.rreini.com/tracey/characters.htm#TTUS) that can be used as the basis for this. Rreini 15:17, 7 October 2007 (UTC)

U.S. Citizenship
When did Tracey EMIGRATE officially, and when did she take the oath of CITIZENSHIP??? - SSG Cornelius Seon (Retired) 10:16, 11 October 2007 (UTC)

Does one ever officially emigrate from his/her homeland? I do know she's been in the US much or most of the time since the mid-80's, perhaps dating to when she got married in December 1983. And in this article (http://www.mediabistro.com/fishbowlLA/show_business/ullman_readies_new_showtime_series_66707.asp), she said she took the oath in December 2006 (no specific date, just the month). Rreini 18:35, 11 October 2007 (UTC)

tone
As Ullman had continued her professional relationship with former producer Brooks, only the studio and not Brooks was named in the suit. In fact, Brooks was allowed to videotape his testimony because in an only-in-Hollywood twist he was at that time directing Ullman in the musical I'll Do Anything, which was released as a non musical film. A settlement was reached whereby Ullman would receive a portion of the profits made from the show, although no amount was ever publicly disclosed.

because in an only-in-Hollywood twist he was at that time directing Ullman in the musical I'll Do Anything —Preceding unsigned comment added by 216.93.226.166 (talk) 07:15, 25 April 2008 (UTC)

Simpsons cut as Profits?
"A settlement was reached whereby Ullman would receive a portion of the profits made from the show, although no amount was ever publicly disclosed."

I really hope that's just sloppily worded, or Ullman got stiffed and likely won't see a penny. Hollywood's creative accounting generally sees that there are no profits recorded; the smart agents ensure their people get a cut of the revenue. 203.59.80.62 (talk) 21:25, 31 December 2008 (UTC)

The Simpsons Shorts article says that Ullman's suit was unsuccessful. Here is says that it was settled in her favor. Which was it? 199.73.152.100 (talk) 14:57, 22 January 2009 (UTC)

Parents
Both parents were born in Königshütte in Upper Silesia which was part of Germany back then (yes, Poland today). The name Ullman(n) is German as was about 50 % of the population of Upper Silesia. — Preceding unsigned comment added by 2003:45:4938:51A6:9927:D92D:C273:9C34 (talk) 14:53, 14 March 2015 (UTC)

Ullman was born in Liverpool or in Berks?
Those two are far apart. Calle Widmann (talk) 22:48, 6 May 2015 (UTC)

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title: Talk:Tracey Ullman


text:
Peccary

A peccary (also javelina or skunk pig) is a pig-like ungulate of the family Tayassuidae (New World pigs). They are found throughout Central and South America, Trinidad in the Caribbean, and in the southwestern area of North America. They usually measure between 90 and 130 cm in length, and a full-grown adult usually weighs about 20 to 40 kg. They represent the closest relatives of the family Suidae, which contains pigs and relatives. Together Tayassuidae and Suidae are grouped in the suborder Suina within the order Artiodactyla (even-toed ungulates).

Peccaries are social creatures that live in herds. They are omnivores and eat roots, grubs, and a variety of other foods. They can identify each other by their strong odors. A group of peccaries that travel and live together is called a squadron. A squadron of peccaries averages between six and nine members.

Peccaries first appeared in North America during the Miocene and migrated into South America during the Pliocene–Pleistocene as part of the Great American Interchange.

They are often confused with feral domestic pigs, commonly known as "razorback" hogs in many parts of the United States, when the two occur in the wild in similar ranges.

The Maya kept herds of peccaries, using them in rituals and for food. They are kept as pets in many countries in addition to being raised on farms as a source of food.

Etymology
The word peccary is derived from the Carib word pakira or paquira.

In Portuguese, a peccary is called pecari, porco-do-mato, queixada, tajaçu, among other names like Cateto or Caititu. In Spanish, it is called javelina, jabalí (a word also used to describe wild boar), sajino, or pecarí. The word javelina derives from the Spanish word for "wild boar". In French Guiana and Suriname, the animal is called pakira.

The scientific name Tayassuidae derives from the same source as the Portuguese tajaçu.

Characteristics
A peccary is a medium-sized animal, with a strong resemblance to a pig. Like a pig, it has a snout ending in a cartilaginous disc and eyes that are small relative to its head. Also like a pig, it uses only the middle two digits for walking, although, unlike pigs, the other toes may be altogether absent. Its stomach is not ruminating. Though it has three chambers, it is more complex than those of pigs. Peccaries are foregut fermenters (pigs are hindgut fermenters). This foregut fermentation, similar to but separately evolved from a ruminant, is an example of convergent evolution.

Peccaries are omnivores and will eat insects, grubs, and occasionally small animals, although their preferred foods consist of roots, grasses, seeds, fruit, and cacti—particularly prickly pear. Pigs and peccaries can be differentiated by a number of characteristic, including tails and ear shape. The ears of pigs are large and upright and often pointed while the ears of peccaries are small and rounded. Pigs also have tasseled tails, but peccaries' tails are small and discreet.

The most noticeable difference between pigs and peccaries is the shape of the canine teeth, or tusks. In European pigs, the tusks are long and curve around on themselves, whereas in peccaries, the tusks are short and straight and interlock with each other, prohibiting side-to-side movement of the jaw. The jaws and tusks of peccaries are adapted for crushing hard seeds and slicing into plant roots, and they also use their tusks to defend against predators. The dental formula for peccaries is:

By rubbing the tusks together, they can make a chattering noise that warns potential predators to stay away.

Peccaries are social animals, often forming herds. Over 100 individuals have been recorded for a single herd of white-lipped peccaries, but collared and Chacoan peccaries usually form smaller groups. Such social behavior seems to have been the situation in extinct peccaries as well. The giant peccary (Pecari maximus) of Brazil appears to be less social, primarily living in pairs. Peccaries rely on their social structure to defend territory, protect against predators, regulate temperature, and interact with other members of the species.

Peccaries have scent glands below each eye and another on their backs, though these are believed to be rudimentary in P. maximus. They use the scent to mark herd territories, which range from 75 to 700 acre. They also mark other herd members with these scent glands by rubbing one against another. The pungent odor allows peccaries to recognize other members of their herd, despite their myopic vision. The odor is strong enough to be detected by humans, which earns the peccary the nickname of "skunk pig".

Extant species
Three (possibly four) living species of peccaries are found from the Southwestern United States through Central America and into South America and Trinidad, each in their own genus.
 * Tayassu
 * White-lipped peccary (T. pecari)
 * Catagonus
 * Chacoan peccary (C. wagneri)
 * Dicotyles
 * Collared peccary (D. tajacu)

The collared peccary (Dicotyles tajacu) or "musk hog", referring to the animal's scent glands, occurs from the Southwestern United States into South America and the island of Trinidad. The coat consists of wiry peppered black, gray, and brown hair with a lighter colored "collar" circling the shoulders. They bear young year-round, but most often between November and March, with the average litter size consisting of two to three offspring. They are found in many habitats, from arid scrublands to humid tropical rain forests. The collared peccary is well-adapted to habitat disturbed by humans, merely requiring sufficient cover. They can be found in cities and agricultural land throughout their range.

Notable populations exist in the suburbs of Phoenix and Tucson, Arizona, where they feed on ornamental plants and other cultivated vegetation. There are also urban populations as far north as Sedona, Arizona, where they have been known to fill a niche similar to raccoons and other urban scavengers. In Arizona they are often called by their Spanish name "javelinas". Collared peccaries are generally found in bands of 8 to 15 animals of various ages. They defend themselves if they feel threatened, but otherwise tend to ignore humans.

A second species, the white-lipped peccary (Tayassu pecari), is mainly found in rainforests of Central and South America, but also known from a wide range of other habitats such as dry forests, grasslands, mangrove, cerrado, and dry xerophytic areas. The two main threats to their survival are deforestation and hunting.

The third species, the Chacoan peccary (Catagonus wagneri). It is found in the dry shrub habitat or Chaco of Paraguay, Bolivia, and Argentina. The Chacoan peccary has the distinction of having been first described based on fossils and was originally thought to be an extinct species. In 1975, the animal was discovered in the Chaco region of Paraguay. The species was well known to the native people.

A fourth as yet unconfirmed species, the giant peccary (Dicotyles maximus), was described from the Brazilian Amazon and north Bolivia by Dutch biologist Marc van Roosmalen. Though relatively recently discovered, it has been known to the local Tupi people as caitetu munde, which means "great peccary which lives in pairs". Thought to be the largest extant peccary, it can grow to 1.2 m in length. Its pelage is completely dark gray, with no collars whatsoever. Unlike other peccaries, it lives in pairs, or with one or two offspring. However, the scientific evidence for considering it as a species separate from the collared peccary has later been questioned, leading the IUCN to treat it as a synonym.

During the Late Pleistocene, two extinct peccaries, Mylohyus and Platygonus, were widespread across North America (and in the case of Platygonus, South America), but became extinct at the end of the Pleistocene around 12,000 years ago following the arrival of humans.

Extinct genera
In addition, Tayassuidae have a well-attested fossil record, and numerous extinct genera are known:
 * †Aptenohyus
 * †Cynorca
 * †Egatochoerus
 * †Floridachoerus
 * †Macrogenis
 * †Mckennahyus
 * †Mylohyus
 * †Platygonus
 * †Prochoerus
 * †Prosthennops
 * †Simojovelhyus
 * †Skinnerhyus
 * †Thinohyus
 * †Woodburnehyus

Evolution
Although some taxa from the Old World like the European Miocene Taucanamo have been suggested to be members of Tayussidae, their assignation to the group is equivocal, with a 2017 phylogenetic analysis recovering Taucanamo outside the clade containing suids and peccaries. The oldest unambiguous fossils of peccaries are from the Early Miocene of North America, with the North American Eocene-Oligocene genus Perchoerus, also often considered an early peccary, recovered outside the clade containing peccaries and suids.

Although common in South America today, peccaries did not reach there until about three million years ago during the Great American Interchange, when the Isthmus of Panama formed, connecting North America and South America. At that time, many North American animals—including peccaries, llamas and tapirs—entered South America, while some South American species, such as the ground sloths and opossums, migrated north. Several species of peccary across the genera Platygonus and Mylohyus remained in North America until their extinction following the colonization of the continent by humans via Beringia at the end of the Pleistocene. Today, 2 of the 3 species are relegated to the Neotropical realm, but the collared peccary ranges into northern Mexico and the southwestern United States.

Domestication
Peccaries bear a familial resemblance to true pigs due to their common ancestry, and are in the same suborder as swine (Suina). They have been present in South America since prehistoric times. The earliest scientific description of peccaries in the New World is in Brazil in 1547 and referred to them as "wild pigs".

It has been documented that peccaries were tamed, penned, and raised for food and ritual purposes in the Yucatán, Panama, the southern Caribbean, and Colombia at the time of the Conquest. Archaeological remains of peccaries have been found in Mesoamerica from the Preclassic (or Formative) period up until immediately before Spanish contact. Specifically, peccary remains have been found at Early Formative Olmec civilization sites.

The peccary is not readily suitable for modern captive breeding, lacking suitable characteristics for intensive or semi-intensive systems. Peccaries require a higher age before they are able to give birth (parturition) and have a tendency towards infanticide.

Relation with feral pigs
Recently established Brazilian boar populations are not to be confused with long-established populations of feral domestic pigs, which have existed mainly in the Pantanal for more than 100 years, along with native peccaries. The demographic dynamics of the interaction between feral pig populations and those of the two native species of peccaries (collared peccary and white-lipped peccary) is obscure and is still being studied. The existence of feral pigs could somewhat ease jaguar predation on peccary populations, as jaguars show a preference for hunting pigs when they are available.

title: Peccary


text:
Kingdom (biology)

In biology, a kingdom is the second highest taxonomic rank, just below domain. Kingdoms are divided into smaller groups called phyla (singular phylum).

Traditionally, some textbooks from the United States and Canada used a system of six kingdoms (Animalia, Plantae, Fungi, Protista, Archaea/Archaebacteria, and Bacteria or Eubacteria), while textbooks in other parts of the world, such as the United Kingdom, Pakistan, Bangladesh, India, Greece, Brazil, Spain use five kingdoms only (Animalia, Plantae, Fungi, Protista and Monera).

Some recent classifications based on modern cladistics have explicitly abandoned the term kingdom, noting that some traditional kingdoms are not monophyletic, meaning that they do not consist of all the descendants of a common ancestor. The terms flora (for plants), fauna (for animals), and, in the 21st century, funga (for fungi) are also used for life present in a particular region or time.

Definition and associated terms
When Carl Linnaeus introduced the rank-based system of nomenclature into biology in 1735, the highest rank was given the name "kingdom" and was followed by four other main or principal ranks: class, order, genus and species. Later two further main ranks were introduced, making the sequence kingdom, phylum or division, class, order, family, genus and species. In 1990, the rank of domain was introduced above kingdom.

Prefixes can be added so subkingdom (subregnum) and infrakingdom (also known as infraregnum) are the two ranks immediately below kingdom. Superkingdom may be considered as an equivalent of domain or empire or as an independent rank between kingdom and domain or subdomain. In some classification systems the additional rank branch (Latin: ramus) can be inserted between subkingdom and infrakingdom, e.g., Protostomia and Deuterostomia in the classification of Cavalier-Smith.

Two kingdoms of life
The classification of living things into animals and plants is an ancient one. Aristotle (384–322 BC) classified animal species in his History of Animals, while his pupil Theophrastus (c. 371–c. 287 BC) wrote a parallel work, the Historia Plantarum, on plants.

Carl Linnaeus (1707–1778) laid the foundations for modern biological nomenclature, now regulated by the Nomenclature Codes, in 1735. He distinguished two kingdoms of living things: Regnum Animale ('animal kingdom') and Regnum Vegetabile ('vegetable kingdom', for plants). Linnaeus also included minerals in his classification system, placing them in a third kingdom, Regnum Lapideum.

Three kingdoms of life
In 1674, Antonie van Leeuwenhoek, often called the "father of microscopy", sent the Royal Society of London a copy of his first observations of microscopic single-celled organisms. Until then, the existence of such microscopic organisms was entirely unknown. Despite this, Linnaeus did not include any microscopic creatures in his original taxonomy.

At first, microscopic organisms were classified within the animal and plant kingdoms. However, by the mid–19th century, it had become clear to many that "the existing dichotomy of the plant and animal kingdoms [had become] rapidly blurred at its boundaries and outmoded".

In 1860 John Hogg proposed the Protoctista, a third kingdom of life composed of "all the lower creatures, or the primary organic beings"; he retained Regnum Lapideum as a fourth kingdom of minerals. In 1866, Ernst Haeckel also proposed a third kingdom of life, the Protista, for "neutral organisms" or "the kingdom of primitive forms", which were neither animal nor plant; he did not include the Regnum Lapideum in his scheme. Haeckel revised the content of this kingdom a number of times before settling on a division based on whether organisms were unicellular (Protista) or multicellular (animals and plants).

Four kingdoms
The development of microscopy revealed important distinctions between those organisms whose cells do not have a distinct nucleus (prokaryotes) and organisms whose cells do have a distinct nucleus (eukaryotes). In 1937 Édouard Chatton introduced the terms "prokaryote" and "eukaryote" to differentiate these organisms.

In 1938, Herbert F. Copeland proposed a four-kingdom classification by creating the novel Kingdom Monera of prokaryotic organisms; as a revised phylum Monera of the Protista, it included organisms now classified as Bacteria and Archaea. Ernst Haeckel, in his 1904 book The Wonders of Life, had placed the blue-green algae (or Phycochromacea) in Monera; this would gradually gain acceptance, and the blue-green algae would become classified as bacteria in the phylum Cyanobacteria.

In the 1960s, Roger Stanier and C. B. van Niel promoted and popularized Édouard Chatton's earlier work, particularly in their paper of 1962, "The Concept of a Bacterium"; this created, for the first time, a rank above kingdom—a superkingdom or empire—with the two-empire system of prokaryotes and eukaryotes. The two-empire system would later be expanded to the three-domain system of Archaea, Bacteria, and Eukaryota.

Five kingdoms
The differences between fungi and other organisms regarded as plants had long been recognised by some; Haeckel had moved the fungi out of Plantae into Protista after his original classification, but was largely ignored in this separation by scientists of his time. Robert Whittaker recognized an additional kingdom for the Fungi. The resulting five-kingdom system, proposed in 1969 by Whittaker, has become a popular standard and with some refinement is still used in many works and forms the basis for new multi-kingdom systems. It is based mainly upon differences in nutrition; his Plantae were mostly multicellular autotrophs, his Animalia multicellular heterotrophs, and his Fungi multicellular saprotrophs.

The remaining two kingdoms, Protista and Monera, included unicellular and simple cellular colonies. The five kingdom system may be combined with the two empire system. In the Whittaker system, Plantae included some algae. In other systems, such as Lynn Margulis's system of five kingdoms, the plants included just the land plants (Embryophyta), and Protoctista has a broader definition.

Following publication of Whittaker's system, the five-kingdom model began to be commonly used in high school biology textbooks. But despite the development from two kingdoms to five among most scientists, some authors as late as 1975 continued to employ a traditional two-kingdom system of animals and plants, dividing the plant kingdom into subkingdoms Prokaryota (bacteria and cyanobacteria), Mycota (fungi and supposed relatives), and Chlorota (algae and land plants).

Six kingdoms
In 1977, Carl Woese and colleagues proposed the fundamental subdivision of the prokaryotes into the Eubacteria (later called the Bacteria) and Archaebacteria (later called the Archaea), based on ribosomal RNA structure; this would later lead to the proposal of three "domains" of life, of Bacteria, Archaea, and Eukaryota. Combined with the five-kingdom model, this created a six-kingdom model, where the kingdom Monera is replaced by the kingdoms Bacteria and Archaea. This six-kingdom model is commonly used in recent US high school biology textbooks, but has received criticism for compromising the current scientific consensus. But the division of prokaryotes into two kingdoms remains in use with the recent seven kingdoms scheme of Thomas Cavalier-Smith, although it primarily differs in that Protista is replaced by Protozoa and Chromista.

Eight kingdoms
Thomas Cavalier-Smith supported the consensus at that time, that the difference between Eubacteria and Archaebacteria was so great (particularly considering the genetic distance of ribosomal genes) that the prokaryotes needed to be separated into two different kingdoms. He then divided Eubacteria into two subkingdoms: Negibacteria (Gram-negative bacteria) and Posibacteria (Gram-positive bacteria). Technological advances in electron microscopy allowed the separation of the Chromista from the Plantae kingdom. Indeed, the chloroplast of the chromists is located in the lumen of the endoplasmic reticulum instead of in the cytosol. Moreover, only chromists contain chlorophyll c. Since then, many non-photosynthetic phyla of protists, thought to have secondarily lost their chloroplasts, were integrated into the kingdom Chromista.

Finally, some protists lacking mitochondria were discovered. As mitochondria were known to be the result of the endosymbiosis of a proteobacterium, it was thought that these amitochondriate eukaryotes were primitively so, marking an important step in eukaryogenesis. As a result, these amitochondriate protists were separated from the protist kingdom, giving rise to the, at the same time, superkingdom and kingdom Archezoa. This superkingdom was opposed to the Metakaryota superkingdom, grouping together the five other eukaryotic kingdoms (Animalia, Protozoa, Fungi, Plantae and Chromista). This was known as the Archezoa hypothesis, which has since been abandoned; later schemes did not include the Archezoa–Metakaryota divide.

‡ No longer recognized by taxonomists.

Six kingdoms (1998)
In 1998, Cavalier-Smith published a six-kingdom model, which has been revised in subsequent papers. The version published in 2009 is shown below. Cavalier-Smith no longer accepted the importance of the fundamental Eubacteria–Archaebacteria divide put forward by Woese and others and supported by recent research. The kingdom Bacteria (sole kingdom of empire Prokaryota) was subdivided into two sub-kingdoms according to their membrane topologies: Unibacteria and Negibacteria. Unibacteria was divided into phyla Archaebacteria and Posibacteria; the bimembranous-unimembranous transition was thought to be far more fundamental than the long branch of genetic distance of Archaebacteria, viewed as having no particular biological significance.

Cavalier-Smith does not accept the requirement for taxa to be monophyletic ("holophyletic" in his terminology) to be valid. He defines Prokaryota, Bacteria, Negibacteria, Unibacteria, and Posibacteria as valid paraphyla (therefore "monophyletic" in the sense he uses this term) taxa, marking important innovations of biological significance (in regard of the concept of biological niche).

In the same way, his paraphyletic kingdom Protozoa includes the ancestors of Animalia, Fungi, Plantae, and Chromista. The advances of phylogenetic studies allowed Cavalier-Smith to realize that all the phyla thought to be archezoans (i.e. primitively amitochondriate eukaryotes) had in fact secondarily lost their mitochondria, typically by transforming them into new organelles: Hydrogenosomes. This means that all living eukaryotes are in fact metakaryotes, according to the significance of the term given by Cavalier-Smith. Some of the members of the defunct kingdom Archezoa, like the phylum Microsporidia, were reclassified into kingdom Fungi. Others were reclassified in kingdom Protozoa, like Metamonada which is now part of infrakingdom Excavata.

Because Cavalier-Smith allows paraphyly, the diagram below is an 'organization chart', not an 'ancestor chart', and does not represent an evolutionary tree.

Seven kingdoms
Cavalier-Smith and his collaborators revised their classification in 2015. In this scheme they introduced two superkingdoms of Prokaryota and Eukaryota and seven kingdoms. Prokaryota have two kingdoms: Bacteria and Archaea. (This was based on the consensus in the Taxonomic Outline of Bacteria and Archaea, and the Catalogue of Life). The Eukaryota have five kingdoms: Protozoa, Chromista, Plantae, Fungi, and Animalia. In this classification a protist is any of the eukaryotic unicellular organisms.

Summary
The kingdom-level classification of life is still widely employed as a useful way of grouping organisms, notwithstanding some problems with this approach:
 * Kingdoms such as Protozoa represent grades rather than clades, and so are rejected by phylogenetic classification systems.
 * The most recent research does not support the classification of the eukaryotes into any of the standard systems., no set of kingdoms is sufficiently supported by research to attain widespread acceptance. In 2009, Andrew Roger and Alastair Simpson emphasized the need for diligence in analyzing new discoveries: "With the current pace of change in our understanding of the eukaryote tree of life, we should proceed with caution."

Beyond traditional kingdoms
While the concept of kingdoms continues to be used by some taxonomists, there has been a movement away from traditional kingdoms, as they are no longer seen as providing a cladistic classification, where there is emphasis in arranging organisms into natural groups.

Three domains of life
Based on such RNA studies, Carl Woese thought life could be divided into three large divisions and referred to them as the "three primary kingdom" model or "urkingdom" model.

In 1990, the name "domain" was proposed for the highest rank. This term represents a synonym for the category of dominion (lat. dominium), introduced by Moore in 1974. Unlike Moore, Woese et al. (1990) did not suggest a Latin term for this category, which represents a further argument supporting the accurately introduced term dominion.

Woese divided the prokaryotes (previously classified as the Kingdom Monera) into two groups, called Eubacteria and Archaebacteria, stressing that there was as much genetic difference between these two groups as between either of them and all eukaryotes.

According to genetic data, although eukaryote groups such as plants, fungi, and animals may look different, they are more closely related to each other than they are to either the Eubacteria or Archaea. It was also found that the eukaryotes are more closely related to the Archaea than they are to the Eubacteria. Although the primacy of the Eubacteria-Archaea divide has been questioned, it has been upheld by subsequent research. There is no consensus on how many kingdoms exist in the classification scheme proposed by Woese.

Eukaryotic supergroups
In 2004, a review article by Simpson and Roger noted that the Protista were "a grab-bag for all eukaryotes that are not animals, plants or fungi". They held that only monophyletic groups should be accepted as formal ranks in a classification and that – while this approach had been impractical previously (necessitating "literally dozens of eukaryotic 'kingdoms) – it had now become possible to divide the eukaryotes into "just a few major groups that are probably all monophyletic".

On this basis, the diagram opposite (redrawn from their article) showed the real "kingdoms" (their quotation marks) of the eukaryotes. A classification which followed this approach was produced in 2005 for the International Society of Protistologists, by a committee which "worked in collaboration with specialists from many societies". It divided the eukaryotes into the same six "supergroups". The published classification deliberately did not use formal taxonomic ranks, including that of "kingdom".

In this system the multicellular animals (Metazoa) are descended from the same ancestor as both the unicellular choanoflagellates and the fungi which form the Opisthokonta. Plants are thought to be more distantly related to animals and fungi.

However, in the same year as the International Society of Protistologists' classification was published (2005), doubts were being expressed as to whether some of these supergroups were monophyletic, particularly the Chromalveolata, and a review in 2006 noted the lack of evidence for several of the six proposed supergroups.

, there is widespread agreement that the Rhizaria belong with the Stramenopiles and the Alveolata, in a clade dubbed the SAR supergroup, so that Rhizaria is not one of the main eukaryote groups. Beyond this, there does not appear to be a consensus. Rogozin et al. in 2009 noted that "The deep phylogeny of eukaryotes is an extremely difficult and controversial problem." , there appears to be a consensus that the six supergroup model proposed in 2005 does not reflect the true phylogeny of the eukaryotes and hence how they should be classified, although there is no agreement as to the model which should replace it.

Comparison of top level classification
Some authors have added non-cellular life to their classifications. This can create a "superdomain" called "Acytota", also called "Aphanobionta", of non-cellular life; with the other superdomain being "cytota" or cellular life. The eocyte hypothesis proposes that the eukaryotes emerged from a phylum within the archaea called the Thermoproteota (formerly known as eocytes or Crenarchaeota).

Viruses
The International Committee on Taxonomy of Viruses uses the taxonomic rank "kingdom" in the classification of viruses (with the suffix -virae); but this is beneath the top level classifications of realm and subrealm.

There is ongoing debate as to whether viruses can be included in the tree of life. The arguments against include the fact that they are obligate intracellular parasites that lack metabolism and are not capable of replication outside of a host cell. Another argument is that their placement in the tree would be problematic, since it is suspected that viruses have various evolutionary origins, and they have a penchant for harvesting nucleotide sequences from their hosts.

On the other hand, there are arguments in favor of their inclusion. One of these comes from the discovery of unusually large and complex viruses, such as Mimivirus, that possess typical cellular genes.

title: Kingdom (biology)


text:
Nicholas I

Nicholas I may refer to:

 * Pope Nicholas I (c. 800–867), or Nicholas the Great
 * Nicholas Mystikos (852–925), Patriarch Nicholas I of Constantinople
 * Nicholas I (bishop of the Isles) (fl. 1147–1152), Bishop-elect of the Isles
 * Nicholas I, Lord of Mecklenburg (died 1200)
 * Nicholas I of Transylvania (died after 1203), voivode of Transylvania
 * Nicholas I (bishop of Schleswig) (died 1233)
 * Patriarch Nicholas I of Alexandria, Greek Patriarch of Alexandria between 1210 and 1243
 * Nicholas I, Duke of Troppau (c. 1255–1318), natural son of king Ottokar II of Bohemia, became Duke of Troppau in Silesia
 * Nicholas I, Lord of Rostock (died 1314)
 * Nicholas I, Count of Tecklenburg (died 1367)
 * Nicholas I Garai (died 1386), chief governor of Bratislava, palatine to the King of Hungary
 * Nicholas I of Opole (c. 1424–1476)
 * Nicholas I, Duke of Lorraine (1448–1473)
 * Nicolaus I Bernoulli (1687–1759); Swiss mathematician
 * Nicholas I, Prince Esterházy (1714–1790), Hungarian prince
 * Nicholas I of Russia (1796–1855), Emperor of Russia and King of Poland
 * Nikola I Petrović-Njegoš (1841–1921), King of Montenegro

title: Nicholas I


text:
United States Department of the Treasury

The Department of the Treasury (USDT) is the national treasury and finance department of the federal government of the United States, where it serves as an executive department. The department oversees the Bureau of Engraving and Printing and the U.S. Mint. These two agencies are responsible for printing all paper currency and minting coins, while the treasury executes currency circulation in the domestic fiscal system. The USDT collects all federal taxes through the Internal Revenue Service; manages U.S. government debt instruments; licenses and supervises banks and thrift institutions; and advises the legislative and executive branches on matters of fiscal policy. The department is administered by the secretary of the treasury, who is a member of the Cabinet. The treasurer of the United States has limited statutory duties, but advises the Secretary on various matters such as coinage and currency production. Signatures of both officials appear on all Federal Reserve notes.

The department was established by an Act of Congress in 1789 to manage government revenue. The first secretary of the treasury was Alexander Hamilton, who was sworn into office on September 11, 1789. Hamilton was appointed by President George Washington on the recommendation of Robert Morris, Washington's first choice for the position, who had declined the appointment. Hamilton established the nation's early financial system and for several years was a major presence in Washington's administration. The department is customarily referred to as "Treasury", solely, without any preceding article, as a remnant of the country's transition from British to American English during the late 18th century. Hamilton's portrait appears on the obverse of the ten-dollar bill, while the Treasury Department building is depicted on the reverse.

Revolutionary period
The history of the Department of the Treasury began in the turmoil of the American Revolution, when the Continental Congress at Philadelphia deliberated the crucial issue of financing a war of independence against Great Britain. The Congress had no power to levy and collect taxes, nor was there a tangible basis for securing funds from foreign investors or governments. The delegates resolved to issue paper money in the form of bills of credit, promising redemption in coin on faith in the revolutionary cause. On June 22, 1775, only a few days after the Battle of Bunker Hill, the Continental Congress issued $2 million in bills; on July 25, 28 citizens of Philadelphia were employed by Congress to sign and number the currency.

On July 29, 1775, the Second Continental Congress assigned the responsibility for the administration of the revolutionary government's finances to joint Continental treasurers George Clymer and Michael Hillegas. Congress stipulated that each of the colonies contribute to the Continental government's funds. To ensure proper and efficient handling of the growing national debt in the face of weak economic and political ties between the colonies, the Congress, on February 17, 1776, designated a committee of five to superintend the treasury, settle accounts, and report periodically to the Congress. On April 1, a Treasury Office of Accounts, consisting of an auditor general and clerks, was established to facilitate the settlement of claims and to keep the public accounts for the government of the United Colonies. With the signing of the Declaration of Independence on July 4, 1776, the newborn republic as a sovereign nation was able to secure loans from abroad.

Despite the infusion of foreign and domestic loans, the united colonies were unable to establish a well-organized agency for financial administration. Michael Hillegas was first called Treasurer of the United States on May 14, 1777. The Treasury Office was reorganized three times between 1778 and 1781. The $241.5 million in paper Continental bills devalued rapidly. By May 1781, the dollar collapsed at a rate of from 500 to 1000 to 1 against hard currency. Protests against the worthless money swept the colonies, giving rise to the expression "not worth a Continental". The office has, since the late 18th century, been customarily referred to as the singular "Treasury", without any preceding article, as a remnant of the country's transition from British to American English. For example, the department notes its guiding purpose as "Treasury's mission" instead of "the Treasury's mission."

Robert Morris was designated Superintendent of Finance in 1781 and restored stability to the nation's finances. Morris, a wealthy colonial merchant, was nicknamed "the financier" because of his reputation for procuring funds or goods on a moment's notice. His staff included a comptroller, a treasurer, a register, and auditors, who managed the country's finances through 1784, when Morris resigned because of ill health. The treasury board, consisting of three commissioners, continued to oversee the finances of the confederation of former colonies until September 1789.

Creation of the Treasury
The First United States Congress convened in New York City on March 4, 1789, marking the beginning of government under the U.S. Constitution. On September 2, 1789, Congress created a permanent institution for the management of government finances:"Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That there shall be a Department of Treasury, in which shall be the following officers, namely: a Secretary of the Treasury, to be deemed head of the department; a Comptroller, an Auditor, a Treasurer, a Register, and an Assistant to the Secretary of the Treasury, which assistant shall be appointed by the said Secretary."Alexander Hamilton took the oath of office as the first secretary of the treasury on September 11, 1789. Hamilton had served as George Washington's aide-de-camp during the American Revolutionary War and was influential in the ratification of the Constitution. Hamilton's financial and managerial acumen made him a logical choice for addressing the problem of the new nation's heavy war debt. His first official act as secretary was to submit a report to Congress in which he laid the foundation for the nation's financial health.

To the surprise of many legislators, he insisted upon federal assumption and dollar-for-dollar repayment of the country's $75 million debt in order to revitalize the public credit: "[T]he debt of the United States was the price of liberty. The faith of America has been repeatedly pledged for it, and with solemnities that give peculiar force to the obligation." Hamilton foresaw the development of industry and trade in the United States, suggesting that government revenues be based upon customs duties. His sound financial policies also inspired investment in the Bank of the United States, which acted as the government's fiscal agent.

The Department of Treasury believes their seal was created by Francis Hopkinson, the treasurer of loans. He submitted bills to Congress in 1780 that authorized the design of department seals, including a seal for the Board of Treasury. While it is not certain that Hopkinson designed the seal, it closely resembles others he created.

2003 reorganization
The U.S. Congress transferred several agencies that had previously been under the aegis of the Treasury Department to other departments as a consequence of the September 11 attacks. Effective January 24, 2003, the Bureau of Alcohol, Tobacco and Firearms (ATF), which had been a bureau of the department since 1972, was extensively reorganized under the provisions of the Homeland Security Act of 2002. The law enforcement functions of ATF, including the regulation of legitimate traffic in firearms and explosives, were transferred to the Department of Justice as the Bureau of Alcohol, Tobacco, Firearms, and Explosives (BATFE). The regulatory and tax collection functions of ATF related to legitimate traffic in alcohol and tobacco remained with the treasury at its new Alcohol and Tobacco Tax and Trade Bureau (TTB).

Effective March 1, 2003, the Federal Law Enforcement Training Center, the United States Customs Service, and the United States Secret Service were transferred to the newly created Department of Homeland Security ("DHS").

2020 data breach
In 2020, the Treasury suffered a data breach following a cyberattack likely conducted by a nation state adversary, possibly Russia. This was in fact the first detected case of the much wider 2020 United States federal government data breach, which involved at least eight federal departments.

Basic functions
The basic functions of the Department of the Treasury mainly include:
 * Producing all currency and coinage of the U.S.;
 * Collecting taxes, duties and money paid to and due to the U.S.;
 * Paying all bills of the U.S.;
 * Managing the federal finances;
 * Managing government accounts (including the Treasury General Account) and the United States public debt;
 * Supervising national banks and thrift institutions;
 * Advising on domestic and international financial, monetary, economic, trade and tax policy (fiscal policy being the sum of these);
 * Enforcing federal finance and tax laws;
 * Investigating and prosecuting tax evaders;
 * Publishing statistical reports.

With respect to the estimation of revenues for the executive branch, Treasury serves a purpose parallel to that of the Office of Management and Budget for the estimation of spending for the executive branch, the Joint Committee on Taxation for the estimation of revenues for Congress, and the Congressional Budget Office for the estimation of spending for Congress.

From 1830 until 1901, responsibility for overseeing weights and measures was carried out by the Office of Standard Weights and Measures under the auspices of the Treasury Department. After 1901, that responsibility was assigned to the agency that subsequently became known as the National Institute of Standards and Technology.

Organization
The Department of the Treasury is organized into two major components: the departmental offices and the operating bureaus. The departmental offices are primarily responsible for the formulation of policy and management of the department as a whole, while the operating bureaus carry out the specific operations assigned to the department.

Structure

 * Secretary of the Treasury
 * Deputy Secretary of the Treasury
 * Treasurer of the United States
 * Bureau of Engraving and Printing
 * Bureau of Engraving and Printing Police
 * United States Mint
 * United States Mint Police
 * Under Secretary for Domestic Finance
 * Assistant Secretary for Financial Institutions
 * Office of Financial Institutions
 * Assistant Secretary for Financial Markets
 * Office of Financial Markets
 * Fiscal Assistant Secretary
 * Office of Fiscal Service
 * Bureau of the Fiscal Service

 * Under Secretary for International Affairs
 * Assistant Secretary for International Markets and Development
 * Assistant Secretary for International Finance
 * Assistant Secretary of the Treasury for Investment Security
 * Office of Environment and Energy
 * Under Secretary for Terrorism and Financial Intelligence (Office of Terrorism and Financial Intelligence)
 * Assistant Secretary for Terrorist Financing
 * Office of Terrorist Financing and Financial Crimes
 * Assistant Secretary for Intelligence and Analysis
 * Office of Intelligence and Analysis
 * Financial Crimes Enforcement Network
 * Office of Foreign Assets Control
 * Treasury Executive Office for Asset Forfeiture
 * Assistant Secretary of the Treasury for Management / Chief Financial Officer / Performance Improvement Officer
 * Office of Small and Disadvantaged Business Utilization
 * Chief Information Officer
 * Assistant Secretary for Economic Policy
 * Assistant Secretary for Legislative Affairs
 * Assistant Secretary for Public Affairs
 * Assistant Secretary for Tax Policy
 * Climate Counselor
 * Commissioner of Internal Revenue
 * Internal Revenue Service
 * Office of the Comptroller of the Currency
 * Office of Financial Research
 * Office of the General Counsel
 * Office of the Inspector General
 * Treasury Inspector General for Tax Administration (TIGTA)
 * Chief Risk Officer

Budget and staffing
The Treasury Department has authorized a budget for Fiscal Year 2015 of $22.6 billion. The budget authorization is broken down as follows:

Freedom of Information Act processing performance
In the latest Center for Effective Government analysis of the fifteen federal agencies that receive the most Freedom of Information Act FOIA requests, published in 2015 (using 2012 and 2013 data, the most recent years available), the treasury failed to earn a satisfactory overall grade.