Stud Books
Dog breeds are documented in lists of antecedents called a stud book.

Dog breeds that have been documented may be accepted into one of the major registries (kennel clubs) of dog breeds, such as the FCI, KC, AKC, UKC, and other national registries such as the Japan Kennel Club. The registry places the breed into the appropriate category, called a Group. Some Groups may be further subdivided by some registries. When the breed is fully accepted, the stud book is closed and only dogs bred from dogs in the stud book will be accepted for registration. These dogs are referred to as purebred.

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Dog breed clubs, especially of dogs bred for a particular kind of work, may maintain an open stud book and so may not be included in major registries. The dogs are still considered a breed. An example of this would be the Jack Russell Terrier Club of America.

Some dog breeds fit the definition of breed, especially breeds that develop naturally on islands or in isolated areas, but are few in number or have not been sufficiently documented to be registered with one of the major registries. An example of this would be the Kintamani Dog and other rare or independent breeds.

Breeds of dogs can be deliberately created in a relatively short period of time. When they breed true and have been sufficiently documented, they can be accepted by major registries. An example of this is the Cesky Terrier.

Standards
Each dog breed has a written Standard, a list of attributes that standardises the appearance of the breed, written by the breed’s founder or breed club. Dog are judged in Conformation Dog Shows on the basis of how closely the individual dog conforms to the breed standard. Breeding working dogs for show competition may cause appearance to be emphasised to the detriment of working ability.

Groups of dogs mistaken for breeds
Groups of dogs that may be mistaken for breeds include working dogs that are categorized by working style rather than appearance, although they may be of various ancestry and may not breed true. The difference between a named group of working dogs and a breed of dogs can be unclear. Examples would be the huntaway and other livestock dogs of New Zealand, the feist dogs of the southern United States, and the Patagonian sheepdogs of Argentina, which are collies mixed with other working dogs.

Landrace dogs are another grouping that often have been named but are not considered breeds. "Landrace" is a term used for early types domesticated animals, including dogs, where isolated populations of dogs are selected according to human goals; developing over time rather than through modern breeding techniques. An example of a landrace dog would be the dog described as ‘Basset’ as early as 1585. The landrace Basset was developed into the modern breeds of Dachshund and Basset Hound, as well as modern day terrier breeds.

Another group of dogs that may be mistaken for breeds are first-generation crossbreds, bred for hybrid vigor (heterosis) from two purebred dogs. An example of this would be the Labradoodle.

Mixed breed dogs may be offered a form of registration to allow them to participate in organized dog events. Often given the name All-American or AMBOR dog, the name does not signify that dogs so registered are a breed. Dogs must be spayed or neutered to be registered.

Individual dogs or small groups of dogs may use an existing breed name or be given an invented breed name and listed with little or no documentation for a fee with "registry" companies with minimal verification requirements. The dogs are then bred and marketed as a "registered" breed, sometimes as a "rare" or new breed of dogs.
 

Dog breeds are groups of closely related and visibly similar domestic dogs with characteristic traits that are selected and maintained by humans, bred from a known foundation stock. A dog breed reproduces with young that are closely similar in appearance and other attributes to other dogs of the same breed.

A dog breed is represented by a sufficient number of individuals to stably transfer its specific characteristics over generations. Purebred dogs of same breed have similar characteristics of appearance and behavior, primarily because they come from a select set of ancestors who had the same characteristics. An individual dog is defined as a member of a breed through proof of ancestry, using genetic analysis or written records of ancestry. Without such proof, identification of a specific breed is not reliable.

History of Dog Breeds
Aboriginal groups or pariah dogs establish themselves near human population, and further develop and maintain themselves without further selection. Neither they carry any specialized working dog functions. Working, hunting and other functional breeds most likely appeared when there is a demand for certain traits that are prevalent to the extension of the point one can devote his time and efforts to establish and maintain the group of dogs that perfect in certain traits valuable for that individual.

Initially the selections would have centered on domestication and useful behavior such as barking at strange creatures, livestock guarding or hunting ability. Some dog breeds, such as Saluki or New Guinea Singing Dogs , have been bred for specific characteristics for thousands of years. Some working dog breeds such as German Shepherds or Labrador Retriever  are established for hundreds years. Later, dogs were also selected for attractive and distinctive forms, resulting in a vast variety of different breeds. Similar dog breeds are classified by dog registries in Dog Breeds Groups.

At a certain point of dog breed development, group of individuals that have dogs of the same breed unite into a National Breed club, describe their dogs in a specific language by writing a breed standard. They describe the most desirable breed specimen and also specify working abilities, as well as undesirable traits for purebred dogs that can belong to this group of dogs. National Breed Clubs promote dog breeds by joining a local popular dog breed registry, as well as internationally, by joining international organizations. Many traditional dog breeds are recognized by the main breed registries are said to be "purebred".

Development of dog breeds
For the history and development of the dog, see Origin of the domestic dog, Ancient dog breeds, and Dog type.

There is much speculation but little evidence about why canids came to live with or near humans, possibly as long as 100,000 years ago. With the beginnings of agriculture around 12,000 years ago, humans began making use of dogs in various ways, resulting in physical differences between dogs and their wolf ancestors. In earlier times, little was written about dogs, although there were known dog types or landrace dogs, which developed over time with minimal human intervention, to fit in with the environment (including human culture) in which the dogs lived or live. Dog breeds in the modern sense date only to the accurate documenting of pedigrees with the establishment of the English Kennel Club in 1873, in imitation of other stud book registries for cattle and horses.

Many dog breeds today have names of original landrace types, such as the Border Collie. Other landrace types, such as retrievers, have been made more uniform in appearance through selective breeding, and developed into a variety of distinctive breeds. Varieties of purebred dogs kept for working purposes can vary in appearance from purebred dogs of the same breed kept as showdogs and pets.

New dog breeds are being continually created. They are either accidentally or purposely crossbred from existing breeds, developed for a specific style of work, or created just for marketing purposes. Recently discovered semi-feral and landrace types such as the New Guinea Singing Dog have been documented and registered as breeds for purposes of preservation. The Canadian department of agriculture has strict standards for the documenting of what it calls "emerging breeds". Many registries which require minimal documentation are available for registering new and existing breeds of dog. In general, a dog can only be guaranteed to be of a specific breed if it is documented in the stud book of a major dog registry or breed registry

From: wikipedia.org
 

The dog is a domesticated subspecies of the wolf, a mammal of the Canidae family of the order Carnivora. The term encompasses both feral and pet varieties and is also sometimes used to describe wild canids of other subspecies or species. The domestic dog has been one of the most widely kept working and companion animals in human history, as well as being a food source in some cultures. There are estimated to be 400 million dogs in the world.

The dog has developed into hundreds of varied breeds. Height measured to the withers ranges from a few inches in the Chihuahua to a few feet in the Irish Wolfhound; color varies from white through grays (usually called blue) to black, and browns from light (tan) to dark ("red" or "chocolate") in a wide variation of patterns; and, coats can be very short to many centimeters long, from coarse hair to something akin to wool, straight or curly, or smooth.
 
Etymology and related terminology
The English word dog can be traced back to the Old English docga, a "powerful breed of canine". It is only attested since the early 16th century, and of uncertain further origin. The most probable source is Germanic *dukkōn, represented in Old English finger-docce ‘finger-muscle’, and some German and Old Norse words with meanings ‘doll, small block, strong, round’, which may have been applied to pups of a strong breed of dogs.

The English word hound is a cognate of German Hund, Dutch hond, common Scandinavian hund, Icelandic hundur which, though referring to a specific breed group in English, means "dog" in general in the other Germanic languages. Hound itself is derived from the Proto-Indo-European *kwon-, which is the direct root of the Greek κυων (kuōn) and the indirect root of the Latin canis through the variant form *kani-.

In breeding circles, a male canine is referred to as a dog, while a female canine is called a bitch. The father of a litter is called the sire, and the mother of a litter is called the dam. Offspring are generally called pups or puppies until they are about a year old. A group of offspring is a litter. The process of birth is whelping. Many terms are used for dogs that are not purebred.

Taxonomy
The English word dog, in common usage, refers to the domestic pet dog, Canis lupus familiaris. The species was originally classified as Canis familiaris and "Canis familiarus domesticus" by Linnaeus in 1758. In 1993, dogs were reclassified as a subspecies of the gray wolf, Canis lupus, by the Smithsonian Institution and the American Society of Mammalogists. "Dog" is sometimes used to refer collectively to any mammal belonging to the family Canidae (as in "the dog family"), such as wolves, foxes, and coyotes. Some members of the family have "dog" in their common names, such as the Raccoon Dog and the African Wild Dog. A few animals have "dog" in their common names but are not canids, such as the prairie dog.

From: wikipedia.org
 

Every year over 3 million dogs and cats are slaughtered by electrocution, hanging, boiling and being skinned alive. Killed they are caged and transported in crude, unsanitary and disgusting conditions