The evolutionary process of the dog

How did the dog evolve? The origin of the dog, and the zoological classification of the dog belongs to the Vertebrata (Vertebrata) Mammalia (Carnivora) Carnivora (Fissiped)

How dogs evolved

Origin of dogs

Zoological classification of dogs

Dogs belong to the vertebrate phylum Vertebrata

Mammalia (Mammalia)

Carnivora (Carnivora)

Suborder Fissipeda

Canidae

Canis genus (Canis)

Canis species (Canis Familiarisliness)

------ Canidae (canis familiaris) animals include dogs, wolves, foxes, coyotes, jackals, and wild hunting dogs.

Among the canids, the common features of the distant or close relatives of dogs are long, narrow heads, long jaws, and multiple teeth, with the posterior teeth evolving to be cut or chewed and ground to accommodate meat or plant foods.

------ The dental structure of the canine family has allowed these animals to spread throughout the world, from deserts to mountain forests and from frozen polar regions to tropical rainforests.

------ The diversity of today's dog breeds is largely the result of the human selection of strains of dogs.

------60 million years ago a small animal with a long body and short limbs lived in the forest, Miacis, with five claws on its feet, was the ancestor of the dog, civet, bear, civet, hyaena, and cat.

------ million years ago, Miacis evolved into about 40 species of primitive dogs, some of which resemble bears, hyaena, cats, and dogs.

------20 million years ago, Mesocyon emerged as a canine-like animal with shorter jaws than modern dogs, a longer body and tail, and stubby legs. The hind legs had five separate claws (modern dogs have four claws).

------ Tomarctus, a 10-15 million-year-old fossil, is a canine with long jaws and a large brain***. All the social*** of the dog is already available.

------ True canids (canis) appeared 5 to 7 million years ago and had four-clawed feet.

------ An Etruscan wolf appeared in Eurasia about 1 million years ago. The Etruscan wolf is probably the ancestor of today's wolves and dogs.

------ The early theory that dogs are descendants of wolves, foxes, or hybrids of wolves and wolves is no longer accepted, and the latest view is that gray wolf are the direct ancestor of dogs.

I don't know when we started to compare dogs with wolves. The most common one that resembles wolves is probably the "wolf dog". Since childhood, we like to discuss whether wolves are powerful or big wolf dogs are powerful, and we have been fascinated by the stories of big wolf dogs fighting against fierce wolves to save their masters. But how did the dog come to be, and what is the origin of the dog and the wolf?

The origin of dogs can be compared to the pyramids as one of the six great mysteries in the history of human civilization, and the standard legend of the origin of dogs is that humans found them to be useful companions and therefore introduced them into their families. "The notion that dogs emerged at the same time as a human settlement is well established, but solve genetic research has found the opposite.

14,000 years ago, dogs and wolves were a "family," and 14,000 years ago, they went their separate ways. An article in Science suggests that dogs mostly came from wolves in East Asia 15,000 years ago, probably because the gray wolves of East Asia were smaller and easier to domesticate, then spread throughout Asia and Europe, and then participated in the colonization of the New World with humans 14 to 12 million years ago.

And the latest mitochondrial DNA differences study shows that the origin and evolution of dogs far before that, that human breeding dogs should be 130,000 years ago, before the breeding of cattle, sheep, chickens, ducks, and other domestic poultry, is in the earliest of all animals and human dependence. Noori Noonan, an expert in dog research at the College of Charleston, said, "We have always believed that a series of wildlife domestication activities began in East Asia a long time ago. Their domestication history is much older than we think, at least 100,000 years old. At that time, there may have been a 'primitive dog' that sought out, and was content with, the warm hearths and comforting meals provided by humans as protectors, providers and good friends, and in turn, this early wolf-like animal helped humans hunt."

So why are there so many different breeds of dogs nowadays, and all with distinctly different physical appearances? Deborah Lynch explains it this way, "Different dog breeds were formed because, at some time in the distant past, humans were domesticating them for different purposes and thus providing specific services to themselves. Functional factors can often influence the evolution of species, which is why police dogs are often black."

In the latest issue of Nature, published in December 2005, U.S. scientists published a canine genetic map showing that humans have more than 300 more genes than canines; dogs have more than 360 genetic diseases that are identical to humans. Due to long-term selective breeding, many dog breeds are also susceptible to the same genetic diseases as humans, such as cancer, heart disease, deafness, blindness and immune neurological disorders.

Although 99% of all dogs are genetically identical, it is the remaining 1% of genetic differences that determine the breed. Genetically speaking, it is the great differences in the appearance of different dog breeds and their common genetic basis that make dogs a good subject for genetic studies. At the molecular level, there is little change between wolves and dogs: their DNA composition is almost identical.

Evolution of the dog

Many different theories have been developed about the evolution of dogs, and wolves, foxes, and jackals have all been considered direct ancestors of dogs. In the 19th century, the diversification of dog breeds led to a view shared even by Darwin and others - that dogs have more than one wild ancestor. If jackals and wolves, or even coyotes and maned dogs, were bred separately and their offspring were subsequently allowed to interbreed, this would inevitably cause a genetic mixture of these different breeds. It is thus clear that the theory that there is less than one type of dog ancestor is correct. The countless dog breeds in the world, today are the result of the careful selection and breeding of dogs by early humans coupled with genetic variation.

Paleocene Period

Sixty million years ago, there was a small, weasel-like animal in the forest with a long, flexible body, long tail, and short legs called the fine-toothed beast, which was an early ancestor not only of the canine family but also of others such as raccoons, bears, weasels, muskrats, bristling dogs, and cats. It crawled on the soles of its feet, like modern bears, and did not walk on its "toes" like modern dogs. The feet had five separate toes, and the teeth were typical of carnivores. The brain was small, but larger than other primitive carnivores of the same period. At that time, other carnivores were far more numerous than the ceratopsians, but they did not participate in the evolution of the dog and disappeared about 20 million years ago, and most of them even died out long before that.

Oligocene period

By the early Oligocene, about 35 million years ago, the ceratopsians had evolved into a variety of early canids. More than 40 species of primitive canids are scientifically known, some bear-like dogs, some bristle-like dogs, and most surprisingly, cat-like dogs. In addition, there is a dog that resembles the modern dog, and only this dog has been able to live and reproduce to this day.

The Third Miocene Period

By the early Miocene of the third century, about 20 million years ago, a very basic and modern-like dog called Mesocyon emerged, with shorter jaws than modern dogs, a long body and tail, and short, stubby legs. The hind feet were still separated by five toes, unlike modern canines that have four toes together. By the end of the third Miocene, 10-15 million years ago, fossils of Tomarctus, a canid with longer jaws and greater brain capacity, were found. Although it was not as intelligent as a dog, it already had all the **** of a dog pack.

Pliocene period

The first appearance of a true canid was 5-7 million years ago. It began to walk on four toes (the fifth toe gradually degenerated into a residual toe) and was relatively close together, a configuration is well suited to hunting. Quaternary period By the beginning of the Quaternary period, about 1 million years ago, an early wolf, the Etruscan wolf, appeared in Eurasia. Recent studies suggest that the Etruscan wolf may be the direct ancestor of domestic dogs and modern wolves, including the small subspecies of the Middle East and India, Canus Iupus pallipes, an animal closer to dogs than other wolf subspecies. The old belief that dogs came from jackals, foxes, or jackals hybridized with wolves has been discarded. Most people now believe that the dog's direct ancestor may have been an animal very similar to the gray wolf of today.

Between about 54 and 38 million years ago, a distinct group of carnivorous mammals developed, all of which shared a common characteristic of having four-lobed teeth. Many animals have eaten meat since ancient times, but only carnivorous mammals have evolved teeth for crushing and chewing (four premolars of the upper jaw and the first molar of the lower jaw) for cutting animal flesh, so the evolution of the dog can be traced by examining the fossilized teeth of its extinct ancestor.

Chronology of dog evolution

100 to 50 million years ago ------------- Creodon Small carnivorous animals

54 to 38 million years ago ---- Miasti Fossil teeth show that these carnivores survived in the Eocene, and the small animals had spreading claws, suggesting a possible tree-dwelling lifestyle.

Thirty-eight to 26 million years ago ------- Dusky dogs developed in present-day North America and may have been the direct ancestor of the canine family, which were the first creatures with inner ear structures.

19 million years ago ----------------- cynodontids They belonged to the amphibian family of canids

Twelve million years ago ----------------- Tractus Martus In the Middle Ages, forty-two different species of dog-like canids emerged, and Tractus Martus had the first models of the dental structure of modern dogs.

The domestic dog is a descendant of carnivorous mammals that had a unique role in biting off meat with split teeth millions of years ago. 10 genera of carnivores were already formed in the canine family 2 million years ago. The canine carnivores consisted of coyotes, jackals, and wolves. When humans began to settle, wolves followed suit and gradually changed their lifestyle. This led to an environment of selective evolution and the gradual formation of the domestic dog.

Creedon Small carnivores 100 to 50 million years ago

Micos 54-38 million years ago

Fossil teeth reveal that these carnivores lived in the Eocene. These small animals had spreading claws, indicating that they probably lived in trees.

Dusky Dogs 38 to 26 million years ago

Dusky dogs lived in North America and are probably the direct ancestor of the canine. This is the oldest breed with inner ears, a characteristic of canids.

Temas 19 million years ago

Carnivorous mammals evolved independently in different parts of the world. Temas evolved in continental Europe, but recent studies have found much disagreement with this hypothesis.

Lepidus 12 million years ago

In Miocene reality, about 26 to 7 million years ago, 42 species of carnivores of different genera and all similar to dogs appeared. Of these mammals, the Lepus is now known to be the true ancestor of the canine and all other modern carnivorous mammals.

Modern dogs 2 million years ago

By the end of the Pliocene and early Pleistocene centuries, 2 million years ago, the basic lineage of all modern carnivores had evolved. 42 species of carnivores had been drastically reduced to 10 species today. The most numerous of these animals is the genus Canis, of which wolves, jackals, coyotes, and dogs are members. The second classification, the genus Fox, has 12 species of foxes.

Dogs are man's most loyal friends, how long is this love affair? After a series of genetic studies, Chinese and Swiss researchers finally proved that as early as 15,000 years ago, the ancestor of dogs, five or six female wolves living in or near China, were successively domesticated by human packs, so from then on, humans and dogs began to hunt together, bake fire together, evolve together and walk together through a long period......

A team of Chinese and Swiss scientists traces the origin of dogs

Several years ago, the Kunming Institute of Zoology of the Chinese Academy of Sciences started to research dogs, wolves, and other animals, while Peter Savolainen of the Royal Swedish Institute of Biotechnology was also conducting related research. 2000, Savolainen and Professor Zhang Yaping, deputy director of the Kunming Institute of Zoology of the Chinese Academy of Sciences, contacted each other, hoping to jointly conduct an in-depth study on mitochondrial DNA diversity in dogs to unravel the mystery of dog origins. The two sides hit it off immediately.

To collect samples, the team traveled to many corners of the world. Zhang Yaping said, "It was challenging work, both from the preliminary design to ensure that representative samples were collected, and the later analysis of DNA samples." But you can hear from his voice that Zhang Yaping enjoys the so-called "hard work".

After 2 years of research, the Sino-Swiss team confirmed that dogs around the world share the same genetic heritage, which originated in East Asia before spreading around the world and making them far more cognitive today than other species. The article was published as the cover paper in the November 22nd issue of Science this year. The article caused a big shock in the field of genetics research, and many scientific publications in Europe and the United States caught wind of it and interviewed Savolainan of the Royal Swedish Institute of Biotechnology, and some genetics research institutions even made the study of dogs their next project.

Mitochondrial DNA unravels the mystery of the origin

Indeed, there is a consensus that dogs originated from wolves, but there is a wide range of opinions surrounding the exact place and time of origin. So far, the earliest fossil evidence of dogs is a 14,000-year-old fossil jawbone from Germany and another fossil skeleton of a small canid from the Middle East about 12,000 years ago, and this archaeological evidence support that dogs originated in Southwest Asia or Europe. In addition, the extremely rich morphological diversity of different breeds of dogs seems to again favor the hypothesis that dogs originated from different geographical groups of wolves. Therefore, archaeology alone can hardly provide reliable clues to the origin of dogs.

A team of Chinese and Swiss scientists collected DNA samples from 654 dogs from Europe, Asia, Africa, and North America and analyzed the base arrangement of the genetic material of "mitochondrial DNA" inherited through maternal lineage in their bodies and found that these dogs have almost the same genes.

Zhang Yaping said, "We thus concluded that the friendly relationship between humans and dogs can be traced back to 15,000 years ago, when humans in East Asia first began to domesticate animals such as wolves, and gradually brought the domesticated dogs to Europe and even across the Bering Strait to America over a long period."

The reason why East Asia is considered to be the richest genetic type of dogs in East Asia, this at scientists have deduced through genetic testing that the region should be the birthplace of dogs, not the Middle East as has been thought in the past.

Five female wolves make dog history

Savolainan said, "It's amazing that after being domesticated by humans, not out of different genes, they were able to differentiate into various types of dogs with such a huge difference in appearance."

The study was conducted by two international research teams working in tandem. On the other hand, a team of scientists from the United States and Peru, among other countries, compared the alignments of bases in dogs from the North and South American continents and Asia, Europe, and dogs that survived in places like Latin America and Alaska before European colonists arrived on the American continent. It was found that some of the genes of both Latin American and Swedish dogs originated from the Eurasian wolf of the past. This part of the gene was revealed in American domestic dogs before the arrival of European colonists in the Americas in the 15th century. They suggest that dogs originated in East Asia and expanded throughout Asia and Europe, and were then brought to the Americas by the first settlers of the continent across the Bering Strait 14,000 to 12,000 years ago.

The study found that there were at least five pack creators, and since dogs were originally domesticated from wolves, it can be inferred that there were several earliest ancestors of dogs. In addition, from the time of domestication, these five pack creators were at different times, which shows that the domestication of dogs did not happen overnight. Domestication requires a process, and when human society developed to a certain stage, in the East Asian region, different human groups coincidentally accomplished the same work one after another."

Almost all dogs, from Chihuahuas to St. Bernards, tracing their lineage will point to the first few female wolves. A Swedish livestock expert, Per Jensen, believes that the speculation that East Asians were the first to domesticate dogs is "very convincing," and that the fact that the first settlers on the American continent brought dogs with them shows that dogs lived with Asians many years before that.

Domestication predates other livestock and crops

Humans domesticated animals out of a developmental necessity. The domestication of wild animals into domestic livestock was a very important product of human development at one stage. In addition to domestic animals, crops were also domesticated from wild crops, and then, humans were able to shift from dispersal and hunting to gathering and farming, cultivating and raising livestock to provide a stable source of food, thus entering agricultural society.

And dogs are different from other domesticated animals. It is speculated that, from the role of dogs, initially domesticated dogs can help in hunting, transportation, and housekeeping, thus inferring that dogs may be the first domesticated wild animals. Later, in the development of human society, dogs were gradually domesticated with many other functions.

Domestication did not happen overnight

It is noteworthy that Zhang Yaping points out that "the domestication of wolves is unlikely to be an isolated event, but more likely a common practical process in human development." The genetic types of dogs belong to different genetic branches of wolves, showing that human packs in East Asia domesticated different wolf packs into domestic dogs at the same time, which Zhang Yaping said is not a coincidental event.

Charles Vella of Uppsala University in Sweden and Jennifer Renard of the National Museum of History in Washington, D.C., are also researching modern dogs. Their research is focused on whether modern domestic dogs were domesticated from the local wolf. They compared the DNA of ancient and modern dogs, including 37 DNA samples taken from fossils of dogs brought to Mexico, Peru, and Bolivia by European settlers, and 11 DNA samples from Alaskan dogs taken from Alaskan sedimentary layers before the arrival of European settlers. The study found that modern dogs are more closely related to ancient dogs than to the American gray wolf, and their similarity suggests that all dogs came from a common ancestor, the Chinese gray wolf. The researchers said, "This means that those humans who traveled to the Americas 13,000 to 14,000 years ago to pioneer must have brought many dogs from their homeland with them."

Why mindfulness is yet to be studied

In the long years of companionship with humans, it has been puzzling that dogs can be mindful of human intentions, so some dogs have been entrusted with important tasks, such as guide dogs, drug detection dogs, and guard dogs. How this intimate relationship between humans and dogs can be explained is still inconclusive.

There is a consensus that dogs originated from wolves, but there are diverse opinions about the specific place and time of origin. The earliest fossil evidence of dogs is from a 14,000-year-old German fossil mandible, and this archaeological evidence supports that dogs originated in Southwest Asia or Europe, while on the other hand, the skeletal identification features of dogs suggest that dogs may have originated from wolves, thus proposing the East Asian origin of dogs. In addition, the extreme morphological diversity of different breeds of dogs seems to favor the hypothesis that dogs originated from different geographical groups of wolves. It is difficult to provide reliable clues about the origin of dogs by archaeology alone.