[arg01]

I wonder if in the case of a technological singularity would you be able to tell that the original species was human? That is to say if we're at the point that we are augmenting our brains to that degree will the difference between a human/dolphin/great ape brain as a base be dwarfed by the technological layers on top of it?

That's getting a bit speculative as a question though. It was more of a thought on how much/how little we might need to change to even constitute not being human.

[infogulch]

You could take the evolutionary viewpoint, where two branches of a species are considered to be distinct when they can no longer breed. Though with the current state of globalization I doubt that could happen... on earth.

[lutusp]

But the human lineage doesn't need to split into branches for us to be replaced by another species -- we might instead simply evolve away from our present form sufficiently that present-day people would not be able to (a) recognize our own descendants as kindred spirits or (b) be able to breed with them (assuming an imaginary biological test in which one of us is propelled 200,000 years into the future).

Modern humans have existed for about 200,000 years. Therefore, natural selection being what it is, chances are in another 200,000 years we will no longer exist in our present form, but be replaced by a new species, one we cannot imagine.