So says Yuval Harari; we will either upgrade ourselves to inorganic lifeforms or go extinct.
http://www.bbc.co.uk/programmes/p045q3yq
All it would take is a meteor mass extinction and who knows perhaps what we now consider the human race would split into separate groups.
Like something out of the time machine with the Morlocks.
What has happened in the past, ( species changing and becoming quite different) could happen again.
When the dinosaurs were wiped out a lot of other things were wiped out too, but other things evolved in their place.
Perhaps it never finishes, evolution.
It's probably arrogant to think we are the last version.