Creator Cameo: The character credited as "Unlucky Bastard" that the T. rex eats in The Lost World is David Koepp, assistant screenwriter to Michael Crichton in the first movie and screenwriter of the second.
Steven Spielberg's reflection can be seen in the TV screen at the end of The Lost World, when Kelly is watching the news. He's eating popcorn.
Creator In-Joke: "You're out of a job", "Don't you mean extinct?" was originally an exchange between Spielberg and Phil Tippett, after seeing an ILM cinematic proving that Tippet's go-motiondinos wouldn't be necessary (Tippett was still kept as an advisor).
Dan Browned: The Spinosaurus being able to snap a T. rex's neck; the third movie's "dinosaur consultant" went on record claiming this was actually possible. In reality, a Spinosaurus's jaws were too weak to do so and their hands and arms were anatomically incapable of holding on to the T-Rex in the manner it does.
Not to mention, T. rex had one of the thickest necks of all predatory dinosaurs, which some scientists speculate it used to pick up medium sized dinosaurs and shake them to death in its jaws, whereas Spinosaurus had a long, thin neck to allow it to move its head quickly into the water to catch fish using its long, narrow jaws. It would be like trying to get a pelican to try to snap a bulldog's neck. Also, the T. Rex had one of the strongest sets of jaws, proportionally, of all creatures to ever exist. The Spinosaurus wouldn't have been able to survive one bite to the neck. Sure, maybe the T. Rex was off its game or something...
Lampshaded by Dr. Grant's remarks at his lecture at the beginning of the movie: he does not consider the Jurassic Park creatures true dinosaurs, but rather genetically engineered monsters. This is shown again by the completely impossible behavior of the Pteranodons. The actual inaccuracies and accuracies in the pterosaurs of the movie are too numerous to list here but anyone who would like to actually look it up can read the Stock Dinosaurs Non Dinosaurs page, which has a whole folder dedicated to describing pterosaurs.
To be frank, the whole 'Spino breaking a Rex's neck' thing is only so hated because T-rex lost, not because of tis scientific innacuracy. there are many more far more drastic bullshit in Jurasic Park- T-rex having a prehensile tongue, poison-spitting Dilophosaurs, eucaptylus chewing sauropods, 10 foot Velociraptors, Dilophosaurus being the size of turkeys....frankly, messing around with purely hypothetical strength levels is the least of JP's paleontological problems, and if one is truly worried about accuracy there are plenty more stuff one should be annoyed about.
The Film of the Book: The third film is composed 95% of anything from the two novels they didn't put in the previous movies (aviary, cloning lab, river chase...)
Refitted For Sequel: The opening to The Lost World: Jurassic Park is adapted from the opening of the first Jurassic Park book.
Many scenes in Jurassic Park III are from the other two books: The river chase from the first and the aviary and cloning lab from The Lost World. It's been joked that III exists mainly to use up all the bits from the books they couldn't fit into the first two movies.
Cooper being the first one to die, and doing so virtually the second he sets foot on the island, could be a shoutout to Dino Crisis, where a team member named Cooper does the exact same thing.
Stan Winston: The genius responsible for the live-action dinosaurs when the computer guys are taking a break.
Take That: In the third film, Grant and the others are being attacked by the Spinosaurus, so Grant uses the satellite phone to call Ellie for help. Her toddler son picks it up, and he would have gotten it to his mother a lot quicker were he not distracted by another dinosaur....
In The Lost World, there's notable diss to paleontologist Robert T. Bakker. Quick history lesson: Dr. Bakker has been a longtime rival of Dr. Jack Horner, the Jurassic Park series' official paleontological consultant. Horner is well known for having a massive ego (he proudly states that he was the inspiration for Dr. Grant's character), and always seemed to be in a perpetual state of bickering with Dr. Bakker, even on the most petty of speculative topics (such as the T-Rex's eyesight, which there is no way of actually studying). And thus in the Lost World, Dr. Bakker is given his very own Captain Ersatz, a bumbling poser who gets scared out of hiding by a snake, and into the jaws of a T-Rex. Bakker seemingly loved the scene, though.
Dr. Bakker is also dissed in the first film when Tim is pestering Dr. Grant about books that he read wriiten by Bakker and Grant himself. Tim is shut up when he first mentions Bakker by Grant promptly slammming the car door of the jeep Tim is inside of closed.
Some of the sting was probably taken out of all this by the fact that book!Grant is an Expy of Bakker himself.
What Could Have Been: Richard Donner, Tim Burton and Joe Dante were all considered to direct when studios had a bidding war for the material (Donner would have made the film for Columbia, Burton at Warner Bros. and Dante at Fox). In the end, Universal and Spielberg won out since Spielberg was Crichton's first choice to direct (and the studio used the upcoming Schindler's List, which Spielberg had been lobbying to direct, as incentive). But imagine how dark Burton's and Dante's versions would have been.
William Hurt, Harrison Ford, and Richard Dreyfuss were all offered the part of Allan Grant. Julie Binochet and Robin Wright were both considered for the part of Ellie Satler. Sean Connery was offered the role of John Hammond. And Brian Cox auditioned for the part of Robert Muldoon.
Spielberg changed the endings of the first two films in the middle of filming. On the first, the film was supposed to end with the dinosaur fossils in the visitors' center falling on the raptors and crushing them. Would've been a tad anti-climatic. Spielberg realised that the audiences would never forgive him if he didn't bring back the T-rex for one last heroic moment, and so he did. With The Lost World, it was supposed to end with a Pteranadon assault on a helicopter. Spielberg had proposed putting a T-rex in San Diego early on, but was more or less ignored, until he insisted that it was the ending that would be filmed. It is quite safe to say that both endings that found themselves in the movie are better than the planned ones.
The third film's ending changed a lot too; in the original script, the Spinosaurus was attacked by raptors and killed at the end; this was probably changed because in the first movie, the raptors were no match for the T-Rex, and having them bring down an even bigger carnivore that actually killed a T-Rex earlier in the film wouldn´t seem realistic. Also, the helicopter was to be attacked by Pteranodons. And they also considered to have the Spinosaurus attack the marines.
