@Prince of SeraphsObvious issues with the scientific premise are rather easily resolved when it is considered that this was penned in 1990, before there was definitive proof that their DNA would and has
totally decayed by this time. Secondly, and might I add, most importantly, it's a
sci-fi horror novel. There is absolutely nothing not self-consistent in the logic and science introduced in the book. In reference to the frog DNA, this refers to the fact that some species of amphibians are capable of changing their gender when the local environment has a huge disparity between the genders. This is called sequentual hermaphroditism; the most famous species capable of doing this is the clownfish. In the book, because the dinosaurs' genome had decayed at least in part by the time InGen began harvesting it, there were huge gaps in it. There wasn't a way to create an animal from it, so they began filling gaps in wherever they'd fit; they used birds, amphibians, lizards, and basically anything that'd fit.
So, no, these aren't real dinosaurs. They're genetically engineered animals using dinosaur DNA as a base. The method the scientists of Jurassic Park used to control the population was both make sure that the diets of the dinosaurs were controlled so that the only source of lysine on the island came from InGen's food stores, and that every single 'dinosaur' created was
female. This is especially easy to do in cold-blooded lizards, as it's simply a matter of what temperature you keep the egg at during its gestation. However, because of this bastardization of the dinosaurs genetic sequence, especially with amphibian DNA, there were unforeseen side effects, the most obvious and relevant to the story being that all of a sudden, most or even all of the species of dinosaur on the island were capable of this sequential hermaphroditism. due to the
aforementioned dominance of the female gender. This, in turn allowed aforementioned breeding and the troubles caused by it.
Anything else, Prince?