"If I descended from an ape, how come apes are still here?"

I can name one species which has gotten smaller:
the kiwi bird is descended from a larger species.
Since ontogeny recapitulates phylogeny, the kiwi bird lays the proportionately largest eggs.
Don't you feel sorry for Mrs. Kiwi Bird?

I have a reply which is similar to Dr. Adequate's reply:
"If Brazilians descended from the Portuguese, how come Portuguese are still here?"
Obviously, some of the Portugese took the boat to the New World, some were happy where they were.
Same way with chimpanzees and humans.
One portion of the population wandered off and did their own thing, the other portion was happy where they were.Edited by tomato, : corrected misspelling+

dwise, here is a math problem which I hope you can help me with:Paleontologists say that they have hauled in:0 Mesozoic cavemen
2100 Mesozoic dinosaurs
4000 Cenozoic cavemen
0 Cenozoic dinosaursThe age of the dinosaurs lasted about 160 million years.
The age of the cavemen lasted about 3 million years.But Creationists tell us that humans and dinosaurs walked the earth together.
So the tally should be something like:3926 Mesozoic cavemen
2061 Mesozoic dinosaurs
74 Cenozoic cavemen
39 Cenozoic dinosaursI tried to work this out as a chi square problem, but my Excel program wouldn't go that high.
I asked someone with math skills, who said that the chances of zero Mesozoic cavemen and zero Cenozoic dinosaurs, given the Creationist claim, are 220,000,000,000,000,000 to 1.
He didn't actually work it out, but he estimated.Can you work this out?
I would like to do a little more than hand wave.