I read more than you thought I do. But you cannot prove that evolution from species to another species has happened anytime in history. And I dare you or anyone else to prove that. You will only keep talking about billions of years ago or eons to come. But your idea is just speculation.
My two examples are fine by themselves unless someone is an evolution fanatic. Notice that I am not an old fashioned creationist.
I was not throwing accusations of creationism, or worse, at that point, still not now for that matter. That said I hold your examples are very poor ones and there are a variety of better ones out there to look at, not sure how I can justify that beyond the dismissing of them I already did though. I guess I could have gone further on the organs thing and general animal reproduction and how mostly it stays the same but occasionally other things pop out, or indeed fail to copy and the resulting creating might not live long enough to breed or breed well (or it might and then we have classical evolution).
Evolution from one species to another then. This one gets to be fun and a massive length of time is a far more useful concept but I will give it a go.
I have three approaches I would take for this one, assuming the retrovirus thing* from earlier does not fly for you, there may well be more (I am not much of a biologist)
1) General incompatibility within a genetic species -- a female chihuahua and a male great dane (both unarguably dogs) can not produce offspring, let alone the viable ones, and dogs are a relatively recent species/offshoot (40000 years at the high end by most estimates). Now this is not chromosomal variation (not an infallible means of defining species but a very good one) as much as a physics/biological supply issue and so does not count by some of the quite useful definitions out there.
2) In plants at least the blending of species (allopolyploidy, a subset of the general concept of polyploidy). When learning about this sort of thing people often wonder why plants sometimes have more chromosomes and genetic mass than other life forms. Blending plant and animal biology like this is not a great move but not an entirely invalid one either and there are . Grasses are a particularly good area of study here
http://www.plantphysiol.org/content/125/3/1198.full as they do it a lot and as we eat them they are pretty well studied.
The aneuploidy version is probably the more dominant method in animals, and possibly some microorganisms though by different means there, and is the one that takes the time.
3) General chromosomal variation, the aneuploidy thing mentioned above. Chromosomes are a pretty good means of species delineation, the classic example from biology textbooks being the horse, donkey and mule example.
*there has been more than one retrovirus throughout history, however various species have got them after another might have branched off which was otherwise untroubled and thus they provide nice things to compare.
So yeah you will probably not have a nice piece of footage (or multiple pieces showing the pattern) from someone with a time machine, a camera and a DNA swab but the mechanisms are very demonstrable.
