Couple of goofy questions on my mind. Hope this makes some sense or if you can figure out what I'm trying to ask....
If all life on Earth share a common ancestor(CA) and this includes everything, flora and fauna, then does it mean that the CA was a one of a kind happening? What I mean is, did the CA only occur once and survive to multiply or could many of them have come into being at the same time and be the only living things inhabiting an area of the planet before the evolutionary wheels started turning? Obviously at some point the CA started to evolve.
The other thing I wonder about is whether the split into plant and animal life occurred because one benefitted the other. IOW's did the animal side benefit the plants or vice versa? Was the split an evolutionary adaptation? If so then the CA adapted to what?