Great question. Kubrick wanted to keep the ending a little ambiguous so that the viewer was left to his own definition and interpretation of meaning. I came up with two. One of them is this:
Man’s evolution in terms of technology definitely plays a role as we see when the bone (his tool) is thrown upward and becomes the spaceship in form and motion. This was after experiencing the mysterious Monolith (representative of an alien species) in the Dawn of Man. Nevertheless, man’s technology proves to be troublesome in terms of HAL’s “malfunction” and rebellion. Dave outwits HAL and discovers why he was sent to Jupiter. He is then transported to what seems to be some type of holding area or “zoo,” as it were, for other species. (This seems to be through various light speeds and perhaps passage through alternate universes. But the way Dave “sees” and his perception change as well.) Near physical death, the Monolith appears, and Dave points toward the specter in a fashion similar to Adam pointing to God in Da Vinci’s Creation. He continues his evolution into the Starchild and returns to earth.
There’s much more to this, but I don’t enough room. This is only one interpretation.