BRANCHING HUMANITY
Homo sapiens
Humanity will reach a natural evolutionary dead end within two to four generations.
(Though humans will still outnumber mutants for some time, the asymmetrical strength of the latter will result in a shift in dominance—see: The "100 sheep, 10 wolves" argument.)
Homo superior
Mutantdom is the natural evolutionary successor to humanity.
Homo novissima
Post-humanity is a manufactured branch of humanity not restricted by normal evolutionary constraints.
(The problem with a technology-based post-evolutionary state is the inevitable—but naturally occuring—paradigm loop between organic and technological constructs. A machine leap makes a post-human leap possible, and a post-human leap makes a machine leap possible—on and on until one of these two eventually reaches an end state.)