Speciation is phenotypic change.
If we don’t have one species changing into another, we don’t have evolution.
If we don’t have one species changing into another, we still have evolution, because that’s merely change. The change is a consequence of small replication errors, i.e. mutations, during mitosis and other cellular activity.
I’m not my grandfather (or my grandmother), and that’s the consequence of dropping half of the chromosomes for just two generations. And since there are 23 chromosome pairs, I’m not getting an even number from each of my grandparents (iow, it’s not exactly one quarter from each grandparent). Each of us has 64 great-great-great-great-grandparents, which means that, unless there’s been a cousin marriage along one of the lines, at least 18 of those 64 ancestors passed down zero chromosomes to us. They are still the ancestors, because they had to have lived and had offspring, but their genetic information has vanished from at least some of their descendants.
At the 5th-great generation — 128 of them — 82 have left zero to the current generation’s individual. In the next generation back, 210 left nothing. In short, there are (for most of us) 46 lines going back. As genetic sequencing becomes cheaper and quicker, and many, many more are sampled, common ancestry will be easier to figure out (even if no name can be put on it) and each of the 23 chromosome pairs will be grouped by common origin, and the number of groups will probably be in the high teens, at least.