isn’t the neanderthal/sapiens split more recent than this? for how long were we separated before the split?
The number that one usually sees is about 500k years ago. Maybe closer to 700k. But not anywhere near 2M. I haven’t seen anyone who thinks the two populations are distinct species offer a number less than 500k.
Not sure if we know how long the separation was. The earliest Homo remains in Europe are about 1.8M years old, but it’s unclear if that represents a separation date, or if there was gene flow back to African populations.
Just to clarify that last post… Asking how long we were separated before the split doesn’t really make sense. We weren’t separated before the split, by definition.
I think the most common view is that Neanderthals are descendant from H. heidelbergensis, or possibly from H. antecessor (although there is debate over whether those are two separate species).
(Caveat: IANAScientist 
)
I recall reading that some species appear to be more “conservative” than others in their change rate though, and that Homo appears fairly rapid when contrasted with Pan – with the suggestion that our common ancestor was probably quite similar in size and shape to modern examples of Pan, and that even the common ancestor back to the split with gorillas was probably similar.
Presumably a major driver for this is environment; once Pan (and Pan ancestors) were well adapted to their environment why change? Whereas if our ancestors became woodland dwellers (rather than rainforest) with altered diet and other factors, these pressures would have had a major selection effect.
As for can / would breed – if Science Fiction has taught us anything, it is that once humanity gets out amongst the stars the aliens having funny noses, funny ears, tentacles, or being entirely composed of morphogenic protoplasm will not stand in the way of humans trying to mate with them.
Returning to the OP question, which is interesting:
Does this not seem a wee bit artificial, as you have an artificial event… Two separated non technology species would seem to present different issues than our humans.
This probably gets to the core meaning of the OP question (I think the question of random selection from current populations particularly interesting). I believe above some rough estimate of ~500k years for objective (versus behavioural) genetic difference to develop to the point of a probable barrier to ‘natural’ (unaided ex-simple care) reproduction.
Of course, it might be cleaner to remove the space travel concept and just pose a hypothetical as follows, for some reason (undefined in hypothetical), human population dies off except in Brazil and Austranesia. Technological collapse is included. Assuming no other biological factors, and assuming the South American and Austranesian populations that pass through the bottle neck at end crisis do not exceed 10k, how long do they have to be separated before “speciation” (reframing in this manner to remove the reconnection being technology driven, leaving aside the historical reality that recontact would almost certainly occur before speciation)
Not until the year 802701.
Still a debate on separate species or sub-species.
Not much of one anymore, especially since the genetic data has not revealed any evidence of mixing despite thousands of years of co-existence. Sure, there will always be some lumpers who will argue sub-species (or 1 species), but the consensus view is species.
Also, a subspecies is generally only recognized if the two populations occupy different territories, with little or no overlap. Two populations occupying the same territory would make an odd sub-species arrangement. The idea is that if those populations did occupy the same territory, they would become one breeding population.
Here, we had two populations that had a geological barrier between them, preventing mating, but when that barrier was removed, there was little or no evidence of mating. Hence, species.
How extensive is the genetic data, though? Last I heard, there was no evidence for Neanderthal mitochondrial DNA in modern humans, but that just means that there were few or no matings with Neanderthal mothers that led to offspring. But it still leaves open the possibility of matings between Neanderthal fathers and modern-human mothers, which might plausibly occur if they viewed us as more “feminine” and we viewed them as more “masculine”.
The genetic data is spares, but that’s all we have to go from. It’s certainly possible that some future research will reveal a different result, but the facts as we know them now don’t support the hypothesis that we were the same species. Whether interbreeding was prevented by physical or cultural reasons (or some combination) we don’t know.
Frankly, I think it would be astounding if the two populations couldn’t interbreed and produce viable offspring, even if they didn’t. There are no large mammals extant today which are that closely related and that can’t interbreed. Chimps and bonobos split about 2M years ago, and the can interbreed.
I don’t know why, but this garbling of his name cracks me up. What’s a bimbri? A male bimbo?
It’s a male bimbo hummingbird. I’ll leave it to everyone’s imagination what that looks/acts like.
Probably like a cross of a hummingbird with this guy.
I have to admit I thought Colibimbri was pretty funny myself.
Oh fuck off… i am sure I could dream up a defence… God-damned hummingbirds.
No one has taken up my restatement, you whiners.
(and yes okay I spelled the username as I mentally pronounce it, and I have no good explanation why…)