I would disagree over a large part of evolution being hybridizing. Just look at the current aquatics market - almost all of these hybrids would have had no chance of meeting up in their natural habitats. Speciation is not usually (or perhaps better put, rarely) such a random act. Just look at the rather large populations of obviously closely-related species in Central American rivers, yet there are NO hybrids between them found in those river systems. Most of speciation thus far described had to do with small behavioral or morphological adaptations/evolutions giving a competitive edge, and these inheritable characteristics being passed on to offspring. Just look at the genus Herichthys to see speciation in action! {although such roadmaps to speciation are not all the same, to be sure}