She was amazed that it would come so close, but she remembered that this was a national park. All the animals in the park would know that they are protected. (1.1.47)
When human beings try to contain or preserve nature, the natural world changes as a result. Animals don't behave in a national park the way they do out in the wild. These environments are different. This fact creates the illusion that nature can be controlled, but it's just that—an illusion.
Everywhere, extensive and elaborate planting emphasized the feeling that they were entering a new world, a prehistoric tropical world, and leaving the normal world behind. (3.17.1)
Jurassic Park is an attempt to re-create a past natural world for human entertainment. Like the present-day natural world, it evades human control, even more so because it's so alien to the humans.
"We have real dinosaurs out there now. That's what people want to see." (3.21.70)
Hammond believes that his cloned dinosaurs are real. In a sense, they are: they are alive and made from real dinosaur DNA. In another sense, they are not real: they have been modified. They've been engineered to behave in ways real dinosaurs would not have behaved.
"Jurassic Park is not the real world. It is intended to be a controlled world that only imitates the natural world." (3.22.91)
Malcolm and Wu are on the same page here: Jurassic Park isn't reality. While Wu believes his creation can be controlled, Malcolm knows better. Just because it's not "real" doesn't mean you can control it.
Tim noticed the fences and retaining walls were screened by greenery to heighten the illusion of moving through real jungle. (3.23.20)
This illusion is difficult to maintain. Jurassic Park is part zoo, part amusement park, part resort. The "naturalness" of Jurassic Park is an illusion.
"This stegosaur is a hundred million years old. It isn't adapted to our world." (3.27.77)
The Stegosaur has difficulty breathing. The other animals suffer from their own ailments. The climate, weather, and ecosystem of Jurassic Park do not capture the realities of their true, natural habitats, no matter how much effort the park employees put in to make Jurassic Park "authentic." The dinosaurs being sick is a warning sign that things are not going according to plan.
"You ready to live dangerously?" (5.44.6)
Muldoon's repeated question to Gennaro should be the motto for the park… except that it's definitely not the one Hammond has in mind.
"But what are you going to do to my animals?"
"That's not really the question, Mr. Hammond… The question is, what are they going to do to us?" (5.47.65-66)
Muldoon is wise enough to recognize that the humans are not in charge of this "natural world" and its inhabitants. The dinosaurs run the show, even if they seem to be safely behind bars for now.
"But you decide you won't be at the mercy of nature." (6.50.10)
Hammond and the designers of Jurassic Park don't respect nature. They look down upon it and think that they can overcome it. Well, nature has a thing or two to say about that, and it comes back to bite them. Literally.
"The planet has survived everything, in its time. It will certainly survive us." (7.52.10)
Malcolm doesn't buy the concern that human beings have the capacity to destroy the planet. He believes that the planet will outlast whatever human beings do to it. It's just the humans themselves who will be destroyed.