Exactly.
It's my vague impression that you get species that can't interbreed after extended geographic/habitat isolation. But short of that, it's a tangled mess, with complex fertility patterns.
It's my vague impression that you get species that can't interbreed after extended geographic/habitat isolation. But short of that, it's a tangled mess, with complex fertility patterns.
https://en.wikipedia.org/wiki/Interbreeding_between_archaic_...
Some examples of hybrids without human influence (well that's arguable):
https://en.wikipedia.org/wiki/Lonicera_fly
https://en.wikipedia.org/wiki/Red_wolf
The grand daddy of "hybrids" (twelve species):
https://en.wikipedia.org/wiki/Celosia_argentea
from here: https://en.wikipedia.org/wiki/Hybrid_(biology)#Speciation
Also you can go beyond hybrids: https://en.wikipedia.org/wiki/Polyploidy#Types
As an amateur I'd hypothesize if the species diverges and then relocates, but is subject to similar environmental pressure, the morphological changes won't be great enough to prevent the organisms from interfacing and then reproducing.
We've determined this through string similarity algorithms, so really I'd say we can't be completely certain here either.