Rlvlk

Correction: In the fourth movie of the series, the apes had already been brought into the servitude of humans. They had been taught mundane duties such as filing, delivering messages, serving food\drinks and so on. Only the best and brightest were kept and the rest were executed. They had even begun to speak by the end of the fourth. Evolution had a nice helping hand from humans in picking the genetically superior apes. Once the apes were in control, they aided in the de-evolution of the human race (in the 3rd movie, it was shown that a group of intelligent, mutated humans did survive). As far as the geographic\climactic changes, we really have no idea what happened in that 2000 year period. How many nuclear weapons were released? Were there any other outside influences adding to the changes(meteors, earthquakes, volcanoes.)? Or was that even New York shown at the end? The statue of liberty may have been moved after destruction.

Rlvlk

Correction: Dr Zaius explains at the end "they" (the government) knows the true history of the apes and implies he knows the fate of man. How he used technology\science to kill himself. It is not a major stretch of the imagination to believe that the apes decided what technology to keep and which to discard.

Rlvlk