Evolution doesn't really deal with where a species splits in two. If anything, species don't exist. Its an abstract grouping of different entities that tend to be able to reproduce together. It only works thanks to in-between links often dying out. If you took a chimp and a human, and made a chain of every ancestor all the way back until you reached a common ancestor, you wouldn't be able to mark when one species becomes another.
We have a few such cases without needing to use time travel. We often refer to them as ring species, but a single ring species would become multiple species if you had one or two areas of the ring wiped out (based on if it is really an unbroken ring or an arc). That the death of one group of animals turns two other groups of animals from being one species into two shows the underlying problem with our classification system.
Thanks for your reply, glad to be educated in my limited biology knowledge :D. I think I understand your point. Evolution doesn't classify, we do. But doesn't this validate my point? Isn't the chicken vs egg question the same kind of problem made up by man like what we describe as different species? Apart from specialists there is no need for the majority of the population to classify the extinct variations of a ring species. So I assumed classification occurs vertical up to the common ancestor rather than horizontal by dying out variations of a ring species.
My original statement was simplified, maybe "evolution in conjunction with how mankind classifies species" would be more in line with the point I was making. My reasoning behind this is the following: As far as I know, the most accurate way of comparing species is by comparing genetic structure. And the point at which these genetic changes typically happen (maybe there are exceptions) is at reproduction (that's the evolution aspect of my point). This would also be the "earliest" point we could spot a difference.
We have a few such cases without needing to use time travel. We often refer to them as ring species, but a single ring species would become multiple species if you had one or two areas of the ring wiped out (based on if it is really an unbroken ring or an arc). That the death of one group of animals turns two other groups of animals from being one species into two shows the underlying problem with our classification system.