* Domestication: The process of dogs evolving from wolves began around 15,000 to 40,000 years ago. This is a long time, and we don't have concrete evidence for the specific breeds that were present at different stages.
* Selective Breeding: Breed development happened through intentional human intervention. People chose dogs with specific traits, breeding them together and shaping their appearance and behavior over time. This process is ongoing.
* Lack of Fossils: The fossil record doesn't offer detailed information on the evolution of specific dog breeds.
However, we can make some educated guesses based on historical records and genetic studies:
* Ancient Breeds: Some breeds, like the Tibetan Mastiff, have deep roots in ancient history, possibly dating back thousands of years.
* Medieval Breeds: Breeds like the Bulldog and Mastiff were developed in Europe during the Middle Ages, likely for specific tasks like fighting or guarding.
* Modern Breeds: Most modern dog breeds were developed during the 19th and 20th centuries, with a surge in popularity for specific traits and appearances.
In summary, it's more accurate to talk about a timeline of breed development rather than specific dates for each breed's evolution:
* Ancient Times: The beginnings of dog domestication and the development of early breeds.
* Medieval Period: The development of working breeds and the establishment of early dog-breeding practices.
* 19th and 20th Centuries: Rapid development of many modern breeds, often through specific breeding clubs and standards.
Remember, dog breeds are constantly evolving through selective breeding. New breeds are still being created, and existing breeds continue to adapt and change.