Domestication

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Dogs and sheep were among the first animals to be domesticated.

Domestication is a phenomenon whereby a wild biological organism is habituated to survive in the company of, or by the labour of, human beings. Domesticated animals, plants, and other organisms are those whose collective behaviour, life cycle, or physiology has been altered as a result of their breeding and living conditions under careful human control for multiple generations.

The word domestication is also used as a synonym of taming, though this word can apply to a single animal, but domestication concerns a population or a species as a whole.

Humans have brought these populations under their care for a wide range of reasons: to produce food or valuable commodities (such as wool, cotton, or silk), for help with various types of work, transportation and to enjoy as pets or ornamental plants. Plants domesticated primarily for aesthetic enjoyment in and around the home are usually called house plants or ornamentals, while those domesticated for large-scale food production are generally called crops. Likewise, animals domesticated for home companionship are usually called pets while those domesticated for food are called livestock or farm animals.

1 Dates and places of domestication
2 Process of domestication
- 2.1 Domestication of animals
- 2.2 Domestication of plants
3 Degrees of domestication
4 Limits of domestication
5 References
6 See also
7 External links

[edit] Dates and places of domestication

See the table by species below

Since the process of domestication can take a long period of time, and the spread of breed and husbandry techniques is also slow, it is not meaningful to give a single "date of domestication". The methods available to estimate domestication dates introduce further uncertainty, especially when domestication has occurred in the distant past. So the dates given here should be treated with caution; in some cases the evidence is scanty and future discoveries may alter the dating significantly.

Dates and places of domestication are mainly estimated by archaeological methods, more precisely archeozoology. These methods consist of excavating or studying the results of excavation in human prehistorical occupation sites. Animal remains are dated with archaeological methods, the species they belong to is determined, the age at death is also estimated, and if possible the form they had, that is to say a possible domestic form. Various other clues are taken advantage of, such as slaughter or cutting marks. The aim is to determine if they are game or raised animal, and more globally the nature of their relationship with humans. For example the skeleton of a cat found buried close to humans is a clue that it may have been a pet cat. The age structure of animal remains can also be a clue of husbandry, in which animals were killed at the optimal age.

New technologies and especially mitochondrial DNA provide an alternative angle of investigation, and make it possible to reestimate the dates of domestication based on research into the genealogical tree of modern domestic animals.

It is admitted for several species that domestication occurred in several places distinctly. However, this doesn't rule out later crossing inside a species; therefore it appears useless to look for a separate wild ancestor for each domestic breed.

The first animal to be domesticated appears to have been the dog, in the Upper Paleolithic era; this preceded the domestication of other species by several millennia. In the Neolithic a number of important species (such as the goat, sheep, pig and cow) were domesticated, as part of the spread of farming which characterises this period. The goat, sheep and pig in particular were domesticated independently in the Levant and Asia.

The availability of both domesticated vegetable and animal species increased suddenly following the voyages of Christopher Columbus and the contact between the Eastern and Western Hemispheres. This is part of what is referred to as the Columbian Exchange.

There is early evidence of beekeeping, in the form of rock paintings, dating to 13,000 BC.

Recent archaeological evidence from Cyprus indicates domestication of a type of cat by perhaps 7500 BC.

The earliest secure evidence of horse domestication, bit wear on horse molars at Dereivka in Ukraine, dates to around 4000BC. The unequivocal date of domestication and use as a means of transport is at the Sintashta chariot burials in the southern Urals, ca 2000 BC. Local equivalents and smaller species were domesticated from the 2500s BC.

[edit] Approximate dates and locations of first domestication

Species	Date	Location
Dog	15000 BCE ^[1]	Multiple locations
Goat	10000 BCE ^[2]	Asia and Middle East
Sheep	8000 BCE^[3]	Asia and Middle East
Pig	8000 BCE^[4]	China
Cow	8000 BCE^[5]^[6]	India, Middle East, and Sub-sahara
Cat	7000 BC^[7]	Mediterranean Basin
Chicken	6000 BCE^[8]	India and Southeast Asia
Guinea pig	5000 BCE^[9]	Peru
Donkey	5000 BCE^[10]^[11]	Egypt
Water buffalo	4000 BCE	China
Horse	4000 BCE^[12]	Russia
Llama	3500 BCE	Peru
Silkworm	3000 BCE	China
Rock Pigeon	3000 BCE	Egypt, Mediterranean Basin
Bactrian camel	2500 BCE	Central Asia
Dromedary (Arabian camel)	2500 BCE	Arabia
Banteng	Unk	Southeast Asia, Java Island
Gayal	Unk	Southeast Asia
Yak	2500 BCE	Tibet
Goose	1500 BCE	Europe
Chinese Goose	1500 BCE	East Asia
Alpaca	1500 BCE	Peru
Domesticated duck	1000 BCE	China
Muscovy Duck	Ukn.	South America
Reindeer	1000 BCE	Siberia
Guineafowl	Ukn	Africa
Common carp	Ukn	East Asia
Ferret	1500 BCE-500 BCE	Europe
Domesticated turkey	500 BCE	Mexico
Goldfish	Ukn	China
European Rabbit	1600	Europe

Second circle

Species	Date	Location
Honeybee	4000 BCE	Multiple places
Asian Elephant	2000 BCE	Indus Valley civilization
Fallow Deer	1000 BCE	Mediterranean Basin
Indian Peafowl	500 BCE	India
Barbary Dove	500 BCE	North Africa
Japanese Quail (see Quail)	1100-1900	Japan
Canary	1600	Canary Islands, Europe
Mandarin Duck	Unk	China
Mute Swan	1000-1500	Europe

[edit] Modern Domestications

Approximate dates and locations of first domestication
Species	Date	Location
Rat late 1800s England
Fox	1800s	Europe
Mink	1800s	Europe
Hamster	1930s	United States
Dolphin	1950s?	United States, USSR
Deer	1970s	New Zealand

[edit] Old (Ancient) domestication

Some species are said to have been domesticated, but are not any more, either because they have totally disappeared, or since only their domestic form no longer exists. Elephant of North Africa (see War elephant).

[edit] Process of domestication

There is debate within the scientific community over how the process of domestication works. Some researchers give credit to natural selection, wherein mutations outside of human control make some members of a species more compatible to human cultivation or companionship. Others have shown that carefully controlled selective breeding is responsible for many of the collective changes associated with domestication. These categories are not mutually exclusive and it is likely that natural selection and selective breeding have both played some role in the processes of domestication throughout history.

The domestication of wheat provides an example of how natural selection and mutation can play a key role in the process. Wild wheat falls to the ground to reseed itself when it is ripe, but domesticated wheat stays on the stem when it is ripe. There is evidence that this critical change came about as a result of a random mutation near the beginning of wheat's cultivation. Wheat with this mutation was the only wheat harvested and became the seed for the next crop. This wheat was much more useful to farmers and became the basis for the various strains of domesticated wheat that have since been developed.

The example of wheat has led some to speculate that mutations may have been the basis for other early instances of domestication. It is speculated that a mutation made some wolves less wary of humans. This allowed these wolves to start following humans to scavenge for food in their garbage dumps. Presumably something like a symbiotic relationship developed between humans and this population of wolves. The wolves benefited from human food scraps, and humans may have found that the wolves could warn them of approaching enemies, help with hunting, carry loads, provide warmth, or supplement their food supply. As this relationship evolved, humans eventually began to raise the wolves and breed the types of dogs that we have today.

Nonetheless, some researchers maintain that selective breeding rather than mutation or natural selection best explains how the process of domestication typically worked. Some of the most well-known evidence in support of selective breeding comes from an experiment by Russian scientist, Dmitri Belyaev, in the 1950s. His team spent many years breeding the Silver Fox (Vulpes vulpes) and selecting only those individuals that showed the least fear of humans. Eventually, Belyaev's team selected only those that showed the most positive response to humans. He ended up with a population of grey-coloured foxes whose behavior and appearance was significantly changed. They no longer showed any fear of humans and often wagged their tails and licked their human caretakers to show affection. More importantly, these foxes had floppy ears, smaller skulls, rolled tails and other traits commonly found in dogs.

Despite the success of this experiment, some scientists believe that selective breeding cannot always achieve domestication. They point out that known attempts to domesticate several kinds of wild animals in this way have failed repeatedly. The zebra is one example. It is possible that the historical process of domestication cannot be fully explained by any one principle acting alone. Some combination of natural selection and selective breeding may have played a role in the domestication of the various species that humans have come into close contact with throughout history.

[edit] Domestication of animals

According to evolutionary biologist Jared Diamond, animal species must meet six criteria in order to be considered for domestication:

Flexible diet — Creatures that are willing to consume a wide variety of food sources and can live off less cumulative food from the food pyramid (such as corn or wheat) are less expensive to keep in captivity. Most carnivores can only be fed meat, which requires the expenditure of many herbivores.
Reasonably fast growth rate — Fast maturity rate compared to the human life span allows breeding intervention and makes the animal useful within an acceptable duration of caretaking. Large animals such as elephants require many years before they reach a useful size.
Ability to be bred in captivity — Creatures that are reluctant to breed when kept in captivity do not produce useful offspring, and instead are limited to capture in their wild state. Creatures such as the panda and cheetah are difficult to breed in captivity.
Pleasant disposition — Large creatures that are aggressive toward humans are dangerous to keep in captivity. The African buffalo has an unpredictable nature and is highly dangerous to humans. Although similar to domesticated pigs in many ways, American peccaries and Africa's warthogs and bushpigs are also dangerous in captivity.
Temperament which makes it unlikely to panic — A creature with a nervous disposition is difficult to keep in captivity as they will attempt to flee whenever they are startled. The gazelle is very flighty and it has a powerful leap that allows it to escape an enclosed pen.
Modifiable social hierarchy — Social creatures that recognize a hierarchy of dominance can be raised to recognize a human as its pack leader. Bighorn sheep cannot be herded because they lack a dominance hierarchy, whilst antelopes and giant forest hogs are territorial when breeding and cannot be maintained in crowded enclosures in captivity.

A herding instinct arguably aids in domesticating animals: tame one and others will follow, regardless of chiefdom.

[edit] Domestication of plants

See agriculture for additional information on early crop use.

The earliest human attempts at plant domestication occurred in Asia. There is early evidence for conscious cultivation and trait selection of plants by pre-Neolithic groups in Syria: grains of rye with domestic traits have been recovered from Epi-Palaeolithic (ca. 11,000 BC) contexts at Abu Hureyra in Syria, but this appears to be a localised phenomenon resulting from cultivation of stands of wild rye, rather than a definitive step towards domestication.

By 10,000 BC the bottle gourd (Lagenaria siceraria) plant, used as a pre-ceramic technology container, appears to have been domesticated. The domesticated bottle gourd reached the Americas from Asia by 8000 BC, probably with peoples migrating into the continent from Asia[2].

Cereal crops were first domesticated around 9000 BC in the Fertile Crescent in the Middle East. The first domesticated crops were generally annuals with large seeds or fruits. These included pulses such as peas and grains such as wheat.

The Middle East was especially suited to these species; the dry-summer climate was conducive to the evolution of large-seeded annual plants, and the variety of elevations led to a great variety of species. As domestication took place humans began to move from a hunter-gatherer society to a settled agricultural society. This change would eventually lead, some 4000 to 5000 years later, to the first city states and eventually the rise of civilization itself.

Domestication was gradual, a process of trial and error that occurred slowly. Over time perennials and small trees began to be domesticated including apples and olives. Some plants were not domesticated until recently such as the macadamia nut and the pecan.

In different parts of the world very different species were domesticated. In the Americas squash, maize, and beans formed the core of the diet. In East Asia rice, and soy were the most important crops. Some areas of the world such as Southern Africa, Australia and California and southern South America never saw local species domesticated.

Over the millennia many domesticated species have become utterly unlike their natural ancestors. Corn cobs are now dozens of times the size of their wild ancestors. A similar change occurred between wild strawberries and domesticated strawberries.

[edit] Degrees of domestication

The boundaries between surviving wild populations and domestic clades of elephants, for example, can become vague. This is due to their slow growth. Similar problems of definition arise when, for example, domesticated cats go feral. A classification system that can help solve this confusion might be set up on a spectrum of increasing domestication:

Wild: These species experience their full life cycles without deliberate human intervention.
Raised at zoos or botanical gardens: These species are nurtured and sometimes bred under human control, but remain as a group essentially indistinguishable in appearance or behaviour from their wild counterparts. (It should be noted that zoos and botanical gardens sometimes exhibit domesticated or feral animals and plants such as camels, mustangs, and some orchids.)
Raised commercially: These species are ranched or farmed in large numbers for food, commodities, or the pet trade, but as a group they are not substantially altered in appearance or behavior. Examples include the elephant, ostrich, deer, alligator, cricket, pearl oyster, and ball python. (These species are sometimes referred to as partially domesticated.)
Domesticated: These species or varieties are bred and raised under human control for many generations and are substantially altered as a group in appearance or behaviour. Examples include the Canary, Pigeons, the Budgerigar, the peach-faced Lovebird, dogs, cats, sheep, cattle, chickens, llamas, guinea pigs and laboratory mice.

This classification system does not account for several complicating factors: genetically modified organisms, feral populations, and hybridization. Many species that are farmed or ranched are now being genetically modified. This creates a unique category because it alters the organisms as a group but in ways unlike traditional domestication. Feral organisms are members of a population that was once raised under human control, but is now living and multiplying outside of human control. Examples include mustangs. Hybrids can be wild, domesticated, or both: a liger is a hybrid of two wild animals, a mule is a hybrid of two domesticated animals, and a beefalo is a cross between a wild and a domestic animal.

A great difference exists between a tame animal and a domesticated animal. The term "domesticated" refers to an entire species or variety while the term "tame" can refer to just one individual within a species or variety. Humans have tamed many thousands of animals that have never been truly domesticated. These include the elephant, giraffes, and bears. There is debate over whether some species have been domesticated or just tamed. Some state that the elephant has been domesticated, while others argue the cat has never been. One dividing line is whether a specimen born to wild parents would differ in behavior from one born to domesticated parents. For instance a dog is certainly domesticated because even a wolf (genetically the origin of all dogs) raised from a pup would be very different from a dog.

[edit] Limits of domestication

Despite long enthusiasm about revolutionary progress in farming, few crops and probably even fewer animals ever became domesticated. While the process continues with plants (berryfruits, for example), it appears to have ceased with animals.

Domesticated species, when bred for tractability, companionship or ornamentation rather than for survival, can often fall prey to disease: several sub-species of apples or cattle, for example, face extinction; and many dogs with very respectable pedigrees appear prone to genetic problems.

One side-effect of domestication has been disease. For example, cattle have given humanity various viral poxes, measles, and tuberculosis; pigs gave influenza; and horses the rhinoviruses. Humans share over sixty diseases with dogs. Many parasites also have their origins in domestic animals.

[edit] References

^ See Origin of the domestic dog
^ Melinda A. Zeder, Goat busters track domestication.(physiologic changes and evolution of goats into a domesticated animal), Avril 2000, This article was copied from the English Wikipedia article..
^ Michaël Lallemand, Courte synthèse sur l'histoire du mouton, de la domestication à nos jours, 2002, (French). See also Pre-Historic Zawi Chemi Shanidar, This article was copied from the English Wikipedia article..
^ Giuffra E, Kijas JM, Amarger V, Carlborg O, Jeon JT, Andersson L. The origin of the domestic pig: independent domestication and subsequent introgression., Avril 2000, This article was copied from the English Wikipedia article..
^ Late Neolithic megalithic structures at Nabta Playa (Sahara), southwestern Egypt.
^ Source : Laboratoire de Préhistoire et Protohistoire de l'Ouest de la France [1], (French).
^ .Un chat apprivoisé à Chypre, plus de 7000 ans avant J.C., Press release from the CNRS, April 2004, (French). Original article: J.-D. Vigne, J. Guilaine, K. Debue, L. Haye & P. Gérard, Early taming of the cat in Cyprus, Science, 9 avril 2004.
^ West B. and Zhou, B-X., Did chickens go north? New evidence for domestication, World’s Poultry Science Journal, 45, 205-218, 1989, quoted here, 8 p. This article was copied from the English Wikipedia article.PDF.
^ History of the Guinea Pig (Cavia porcellus) in South America, a summary of the current state of knowledge
^ Beja-Pereira, Albano et al., African Origins of the Domestic Donkey, Science 304, 1781, 18 juin 2004, cité ici, This article was copied from the English Wikipedia article..
^ Roger Blench, The history and spread of donkeys in Africa' This article was copied from the English Wikipedia article.PDF.
^ The Domestication of the Horse ; see also Domestication of the horse