A concept from Vernor Vinge's SF masterpiece series Across Realtime
Human Technology evolves to the point where humans cease to exist in any form recognisably human.
(Less sanguinely) Vinge claims that: "Within thirty years, we will have the technological means to create superhuman intelligence. Shortly thereafter, the human era will be ended."
See http://en.wikipedia.org/wiki/The_Singularity
How is this Tcl related?