Dogs probably derived from wolves, most likely from multiple populations of wolves- at around 135,000 years ago, but evidence shows that domesticated dog started early- at around 13,000-17,000 years ago. The earliest remains were found in Central Russia.

http://www.medindia.net/news/v...
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Dogs probably derived from wolves, most likely from multiple populations of wolves- at around 135,000 years ago, but evidence shows that domesticated dog started early- at around 13,000-17,000 years ago. The earliest remains were found in Central Russia.

http://www.medindia.net/news/v...

Ancestors are not positively certain, but dogs most likely evolved from wolves and/or a species close to a dingo. Some theories suggest that dogs domesticated themselves by living in such close proximity to humans, while others theorize that humans adopted the calmer-natured wolves, then selectively bred them.

Origins of breeds happened as a result of selective breeding (i.e. some dogs that had a calm demeanor were selected as breeders, so other more aggressive dogs were not; some strong-boned dogs were selectively bred as working dogs, while feebler dogs were not.. all depending on preference and function). Dogs were also selectively bred for different appearances (I.E. small or large dogs, long or short fur, spotted or solid coat, etc.)

Even today, breeds have changed quite a bit from 100 years ago- take the Collie: as man selectively breeds collies with narrow snouts over several generations, the collie's snout has narrowed more and more- check out a turn of the century photo of a collie and you will see the difference. As a result, the collie's brain has shrunk in order to fit in its narrowing skull.