The fossil record indicates leaps, not gradual blending. Thus, following the evidence it would seem that evolution proceeds in jumps too. Additionally, the story of "one" species turning into another is misleading. It seems to suggest that one species exists independently of many others. You very body is not entirely human. Something like 20% (don't quote me on this percentage) of your weight contains living organisms that do not share your DNA. Most of these live in your colon, but some live on your skin, in your eyebrows, etc. A human being is a society of many organisms working together. Generally, these organisms keep their DNA to themselves. In some rare cases, DNA from one of these organisms will slip into the genetic code of another. Generally, this alien DNA is unwelcome and not helpful and is short lived. Rarely, such a mingling of DNA results in a symbiotic organism that is better suited to survival in some particular environment. When this happens, there is an evolutionary jump. Although the advancement of a symbiotic relationship turning into new species is rare, it does occur. Evolution is all about the preservation (via natural selection) of these rare and unlikely symbiotic combinations.
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