Darwin.

Darwin's theory of 'survival of the fittest' is bent a little in this article with 'survival of the cutest.'

Basically, dogs back in the day appeared and functioned for survival and shelter. Now dogs get cuter and cuter to be sold for appearance not really for any real function. They can get away with all the variations that affects their functions like breathing and chewing that back in the day would have lead to their extinction. Biologist Dr. Klignenberg says "natural selection has been relaxed and replaced with artificial selection for various shapes that breeders favor." Sometimes evolution takes years to happen; other like this, not very long at all.