A Chihuahua is not a midget Great Dane. In the same way that a human midget is not some kind of distinct human breed.
This thread has gotten outta control. What's your point? Please, say more than simple questions, and act like "I gotcha!!" with every response. How is evolution proven by using the above example????
Dog breeding is an excellent example of how evolution works. The only difference between the processes is that human beings select the traits they want to breed for. It's called 'artificial selection'. Without human interference, it's called 'natural selection' and the traits that each individual possesses that help it survive are the ones that are 'bred' for, simply by the process of dying before they are old enough to reproduce and pass on the genetic material.
It's very simple. Imagine you had 100 golden retrievers out in cages in your back yard. One day, you decide that in the future, all you want to keep are the dogs with the darkest coats. In order to do that, what you might do is select 20 of the 100 dogs (10 male and 10 female) that had the darkest coats and breed them together. This would produce offspring with the highest likelihood of darker coats. Then you would breed only those with the dark coats again, and again, and again. The other 80 dogs, however, have bright coats, so you do not choose to breed them before they eventually die. This is evolution in action. Small steps give you darker and darker coats. The interesting thing is that you can do that with just about every characteristic a dog possesses. Long nose, short legs, fetching capability, etc. It's all been done, little by little. The process by which that happens is called evolution via artificial selection.
In natural selection, the process is the same, however instead of a human being selecting for dark coats, nature will decide whether or not a dark coat is advantageous simply by whether or not a dark coat gives the individual a survival advantage in their environment over others of its kind. This is really not that hard a concept. If the dog lives in the arctic versus the jungle, just imagine what advantages or disadvantages a dark coat might give. Would it be harder to see? Better insulation against the cold? There are lots of possibilities.
Honestly, I would like to know exactly where in that process the whole thing breaks down for you. Don't keep looking at the big picture and saying 'oh, it can never happen, it can never explain everything!'. That is an EMOTIONAL response. Use your brain for a minute. What part of that process do you not think is accurate? Step by step. Which one?