Speciation is a process that takes place over a long period of time. There are, in fact, several species which have arisen within the span of recent human history (the last 10,000 years).
Human and chimpanzee DNA is over 95% the same. Would you say, then, that we are just "mixtures of existing breeds"?
Ha! I’ve never heard that argument before, so I give you points for originality. It does kind of make sense, since it would basically take a miracle for Darwin’s just-so story to happen in reality, according to what we know of biology, physics, and genetics.
The theory as formulated by Darwin and refined by countless scientists since then is very much based in the laws of physics. That you don't understand those laws is not a condemnation of the theory.
“There are, in fact, several species which have arisen within the span of recent human history (the last 10,000 years).”
How do you determine that those are new species and not simply new breeds? Is there an objective standard that can be applied, or is it just “fuzzy science”? If you define species so loosely as to have no objective standard, then saying a new one arises means next to nothing, objectively.
“Human and chimpanzee DNA is over 95% the same. Would you say, then, that we are just “mixtures of existing breeds”?”
Since humans and chimpanzees cannot interbreed, I would say probably not. The test of interbreeding is only conclusive for positive results, not negative ones, since there are breeds that are obviously of the same species (because we have bred them), yet they can no longer interbreed, which are basically false negatives.
“The theory as formulated by Darwin and refined by countless scientists since then is very much based in the laws of physics.”
I like how you didn’t say anything about biology and genetics. Sometimes what you don’t say is as important as what you do. Now, standard evolution doesn’t step on too many toes when it comes to Physics, but abiogenesis certainly does, and that theory is a natural consequence of the same assumptions that figure in to evolution.