"In the beginning was the word and the word was dog and the people made more dogs and used more words to differentiate those dogs until they had more than 400 different kind of dogs and more than enough words to explain the differences." ---Doctor Barkman
Breed standards are one of the tools breeders use to suspend change in purebred dogs. But breeds evolve anyway, even when standards remain unchanged. How is that so?
Exaggerated traits come and go with fashion. If the standard says the skull should be "very short from the point of the nose" to the eye (Bulldog), or "egg shaped" (Bull Terrier), fashion will dictate the length and shape of the head. A note of caution though - breeds are not mix and match combinations of thousands of small parts where you pick and choose what you want. They're more like combinations of genes, pre-packaged in bundles and shuffled around. A whole lot of genetic stuff, good and bad, goes along for the ride when a breeder pulls out a trait.
This is what a Bulldog looked like in 1900
A Bull Terrier in 1900
If the standard says, "The ears are extremely long," in a hundred years the ears will be really, really long.
This is a Bassett Hound in 1900
Some breed haven't changed much in a century. This is the German Pointer in 1900.
A standard is a handy tool for dog show judges who need to evaluate dogs in competition, but it doesn't suspend change. It's really just a lexical snapshot of a breed on its way to being something else. Breeds evolve. It's the breeders job to make sure they evolve in a healthy way.
To read the entire article about how standards influence purebred dogs in unintended ways click here.
(Vintage pictures in this post are from The New Book of the Dog by Robert Leighton, Cassell and Company. London, 1907; contemporary photos are from Wikipedia, The Free Encyclopedia.)