"You have to see it happen, or it doesn't count." If you take that position, or accept Dr. Carson's assertion that it is necessary to demonstrate a species actually changing to another species, then, well, you didn't see the Grand Canyon being made but you know how it happened, right? The only way we can see a rosebud opening--unless you have the patience of a fisherman--is with time-lapse photography. The Burgess shale and evolutionary biology make the doctor's position very difficult to defend. This isn't "faith" we're talking about here, but hard science. If you are requiring an eye-witness, then the only person who really knows may be this trans-species joyful pre-Cambrian tortoise, currently resting and/or pining for the fjords.
In any event--evolution. just. doesn't. care.