[nocut12]

As far as technology, modern humans weren't really too different at the time (in Europe at least). And of course, modern humans and neanderthals were similar enough that we were willing/able to interbreed, which certainly says something.

I do think people overstate how similar we were though -- we don't have any super clear examples of neanderthal artwork (people make arguments, but this stuff isn't exactly Chauvet https://en.wikipedia.org/wiki/Neanderthal#Art). To me, this seems to indicate that their brains might have worked pretty differently.

[benj111]

"we were willing/able to interbreed, which certainly says something"

Does it?

Men like to spread their seed, and I'm not sure what the rules were regarding giving women a choice in the matter. I'm guessing rape wasn't in their vocabulary though.

[AlotOfReading]

The ability to produce viable offspring is generally considered the primary differentiating characteristic between species and subspecies. That's one of a number of arguments in the debate over whether Neanderthals should be named H. neanderthalensis or H. sapiens neanderthalensis.

[ncmncm]

That criterion has had to be abandoned, replaced with "forms reproductive groups with practical boundaries".

Sometimes a river is that boundary, or a preferred prey species, a mating strategy, or odor preference.

Otherwise, we cannot distinguish bear, dog, or great-cat species.

[derefr]

Isn't there already a separate word—subspecies—for "isolated reproductive groups, with different phenotypes, which could still interbreed if the opportunity arose"? My understanding was that every phenotypically-distinct isolated reproductive group was considered a subspecies until its genetics diverged enough to have speciated, at which point it was now a species.

It seems to me that if e.g. American black bears and Asian black bears can interbreed, then we could call them all one species—black bears—and put all their subspecies together in into that taxonomic category. Maybe with some optional taxonomic level between "species" and "subspecies" for describing their phenotypic groupings.

But I see, looking at various sources, that those two types of bears are indeed considered separate species. Why do we do that? What's better/more useful about drawing the species boundary there?

[ncmncm]

"Species" is an organizational convenience for biologists. Nature doesn't have such a boundary. It just has varying degrees of reproductive compatibility, inclination, and opportunity.

"Subspecies" is a concession to what lumpers call splitters.

[derefr]

There is certainly a conservative definition for speciation, though: the point where something has zero reproductive compatibility—where there is no known example of viable offspring. At that point, inclination and opportunity cease to matter.

Why not just define “species” by that clear formal boundary, and then call everything that doesn’t manage to reach that line “subspecies”?

[benj111]

I was addressing the willing rather than the able.