I'm going to lock this thread because it's been asked a zillion times (and everyone who knows the answer tends to get testy about this.)
The question relies on your not knowing a couple of things:
1) you don't know how evolution works.
2) you don't know the human lineage (this last one is something that you can blame the textbooks for. Until you're in college, NO school system
really wants to stand up and teach you what we know, because that will get the Biblical Literalists screaming "Heresy!" and that accusation will
almost always get schools to back down.
So the answer is: evolution occurs when groups of living creatures get separated from other groups and both change to adapt to their new environment.
An example is blind cave fish. These are normal fish (and their kinfolk live just a few miles away and have eyes) that have adapted to living in the
dark. Through a series of mutations and changes, they no longer have eyes and their skin is translucent. This kind of fish survives better in total
darkness than the regular fish.
They started out the same. They're separate species now and will eventually be so different that they can't crossbreed. The ones in the perpetual
dark will grow along evolutionary lines that make them more able to survive in the dark; the others will grow along other lines.
But you're not going to get a "super-blind-cave-fish" suddenly developing out of the regular old fish in the stream.
Apes have enough differences in chromosmes that they won't become humans.
Might they become as intelligent as we are someday? Maybe. We don't know. We don't know what changes they'll go through as we put them in zoos
and preserves and they start interacting with scientists frequently.
And we don't "see" evolutionary changes in something as long-lived as humans or apes. They're there, but it takes perhaps 10 generations for a
mutation to spread extensively in a population (even with human meddling; such as developing a new breed of cat) and up to 100 generations would be a
more likely figure.
We have, however, seen mutations and evolution in short-lived organisms such as bacteria. They do now, however, change into (say) water lillies... we
haven't watched enough generations of bacteria to see that happen. But we do see them evolve.
For more information and the answer to a lot of your questions, see
www.talkorigins.org... 
