The Remake Took Place In The PastThe was This Troper saw it, is that in order to subvert the expected ending (he was on Earth... IN THE FUTURE!) Marky Mark was still on Earth all along... IN THE PAST!(?) Work with me here... the first (what could be called) human beings showed up about 13000 years ago. Perhaps the apes were here before us. Then, their society collapsed, leaving us to pick up the pieces in time for 10,000 BC. By traveling back in the past, Leo severely altered the chain of evolution. The sudden appearance of their mythical savior provided some sort of catalyst that revolutionized their entire civilization, and continue progressing. Thus, the human race was never given the opportunity to evolve, and most likely died out. Or at least became as primitive as the apes we know today.
In the remake he was on Earth the whole timeThe filmmakers tried to do a twist because It Was His Sled, but failed. It was Earth All Along. But in the end, our hero ended up at least one millennium ahead of when he left. His showing off his technology made others understand it. Letting the non-native chimp stay may have screwed everything up, or it may just be technology advancing.
Gibbons/Siamangs are the butt of jokes to other apesGorillas are the military and blue collar workers, Chimps the intellectuals and white collars, and Orangutangs the religious, judiciary and political class. They all live in Ape City. But who is the farmer class that cultivates those maize fields the humans ravage? That's right, the Gibbons. They are small, weak and monogamous to the point of being antisocial. Plus, they run like idiots. They are basically illiterate country bumpkins that live in single pairs attending their own single, isolate farm and land plot, and raising their children themselves to do nothing else. In fact, they usually avoid contact with the cities altogether unless it's time to sell their products or to call the Gorilla army because those pesky humans are ravaging their crops again.
Zaius revealed the truth about Earth's past to Cornelius and Zira at the beginning of BeneathAlone with them in the beach and inquired about the talking doll, he gave in and told them what he knew about the downfall of humanity and Caesar's... ahem, "Aldo's" rebellion. He also considered that with Taylor gone he had no reason to continue their prosecution and dropped the charges against them. Hence why Zira and Cornelius are free and at home in Beneath, and why they know more about the past in Escape than they did in the original film.
Shortly after the Battle For The Planet Of The Apes' epilogue some sort of religious and cultural revolution took place in Ape societyShortly after the Battle For The Planet Of The Apes' epilogue some sort of religious and cultural revolution took place in Ape society. The results were humans being cast out and apes considering themselves racially superior. The sacred scrolls were written (or re-written) to justify this at the time and eventually make this historical event largely unknown to wider Ape society with the religious history in its place. This could have been perpetrated by Aldo sympathisers who replaced Caesar's historical revolution and tolerance of humans, with a mythical set of events where Aldo simply said no more to human barbarity. The ability to speak being lost in the wild human can be explained by a mutated gene being introduced by the slightly mutated humans from the city captured by Caesar at the end of "Battle". By the time Zira and Cornelius are allowed to read the secret historical scrolls more than a thousand years has passed and even these supposedly historical records have been tainted with religious and political agendas.
The slave apes in 'Conquest' were created by splicing human DNA with the apesIt would explain why they all looked so much more human by then. (backstory-wise, they obviously had to use humans in makeup) and were smart enough to perform all those jobs.
Researchers salvaged sperm and eggs from the bodies of the three future apes in Escape and used them to breed the ones from Conquest.Same idea as above, but more consistent with the technology levels exhibited in the fourth film. Plus, it explains why that other ape's ability to stammer "No" at the end was a surprise to everyone, ape or human: her genes hadn't been manipulated deliberately to have human features, she just happened to have enough ancestry from Cornelius, Zira and/or Dr. Milo to have inherited speech by chance.
The ape society of the original film is actually very small, there are human civilizations all over the planet.Taylor and crew only see a small section of the world, being geographically New York City and environs. There's no reason to believe that humans are not the dominant species everywhere else.
The original film quintology and the live-action series are part of the same continuity.First the events of Planet (1968) and Beneath happen, with Taylor crash-landing on the planet of the apes and then destroying it, thus ending "timeline A". Just before the climax of Beneath, Zira, Cornelius and Dr. Milo escape, leading to the events of Escape. The combined results of their presence lead to "timeline B", which covers the events of Conquest and Battle. This ends up creating the Ape-Earth of 3085 that is seen in the TV series; while the apes do come to dominate the world, humans remain intelligent and literate but become second-class citizens (a state that the mixed-primates civilisation in Battle was pretty much at). Thusly, when Taylor's ship crashes on the planet in this timeline, there are no Neo-Neolithic humans to steal their clothes and Taylor and co instead make open contact directly with the apes. Which leads to their deaths at the hands of Urko, as stated in the pilot of the TV series, and so there is no detonation of the cobalt bomb (assuming that the Underdwellers even exist in this time) and thusly the planet never gets destroyed.