I believe in evolution. I dont believe we understand it completely, or even as much as we think we do, but I believe in it, generally speaking.
Selective breeding is not evolution. Its basically the opposite of evolution. Evolution is the idea that random mutations in a population, through reproduction, will create alterations that the environment will either find beneficial, or detrimental. The mutated beings that acquire detrimental mutations will die, while the beings that acquire beneficial mutations will flourish and eventually out-populated the previous life form.
An example is the turtle. Evolution tells us that somewhere back in history, a reptile was born with a shell on its back that, natually, helped protect it from the environment and predators. That shelled creature mated with another, passing on the shell trait. The shelled reptiles out-flourished the non shelled reptile ancestor, thus altering the species' permanent traits.
There is nothing random about selective breeding. And there is no guarantee that what we selectively breed would surpass the current human lifeform, which goes back to the idea that we humans do not know enough about evolution, or the human genome/DNA/development/whatever to even know what to weed out, even if we could be successful at selective breeding.