On their way to the rooms at the resort, Grant thinks about the controversy among scientists over whether dinosaurs were cold-blooded or warm-blooded animals. Sattler notices a poisonous variety of Jurassic-era fern carelessly planted next to a swimming pool. Once in their rooms, Grant and Sattler notice additional bars—which had not appeared in the construction plans—protecting the windows.
Before they depart on a tour of the island, Gennaro tells Grant, Sattler, and Malcolm that he wants to know whether they think the park is safe. He mentions the incident with Tina on Costa Rica, and then refers to reports of lizard attacks and increasing infant mortality rates in Costa Rican costal villages. Malcolm claims that chaos theory implies that animals have gotten off the island, which annoys Hammond. A helicopter arrives with Hammond's grandchildren, an eleven-year-old boy and an eight-year-old girl. The presence of the children annoys Gennaro.
Tim Murphy, Hammond's grandson, is a dinosaur nut and immediately recognizes Dr. Grant. Ed Regis takes everyone to the laboratories, annoyed that he seems to have been put on babysitting duty. In the lab, Dr. Wu explains that they retrieve their dinosaur DNA from biting insects that have been preserved within ancient amber. In the nursery they see a baby velociraptor, which looks like a small lizard that stands upright and has yellow and brown stripes. The raptor jumps into Tim's arms. Dr. Wu explains that, to prevent breeding, their dinosaurs are sterilized and all of them are engineered to be female. Malcolm is skeptical.
Malcolm asks Wu if they had engineered any procompsognathus, or compys—the animal suspected of biting Tina. Wu explains that they had, but that it would be impossible for the animals to get to the mainland because he had engineered all of them to be dependent on lysine, a key nutrient. Without the special supplements the dinosaurs receive at the park, they would go without lysine and die within twelve hours. While visiting the raptor holding pen, Grant notices that one raptor is stalking them from within its cage. Suddenly two other raptors attack from the left and right, but are held back by the electric fence. The speed of the animal reminds Grant of the cassowary, a clawed ostrich-like bird from New Guinea.
Wu approaches Hammond at his bungalow and asks about creating another version of the dinosaurs that currently inhabit the park—version 4.4. Wu claims that the animals are too fast and difficult for the staff to handle, and that the people who visit the parks would probably prefer seeing slower versions anyway. Hammond scoffs at the idea, saying that if they were made slower they would not be real dinosaurs. Wu claims that they are already not real, as they are engineered to begin with, a reconstruction of the past rather than a recreation. Hammond still adamantly refuses to consider the idea.
In the control room, John Arnold, the chief engineer, explains that the animals in the park are monitored and tallied by a variety of computerized methods. Motion sensors cover ninety-two percent of the park and video surveillance equipment keeps constant visual tabs on the animals. Malcolm asks about data studies of the animals, so Arnold shows him a graph of procompsognathid height distribution that appears to be a normal distribution for a healthy biological population. Malcolm states that the graph's seeming normality implies problems with the animals: since Jurassic Park is a controlled environment and not the real world, it should not contain a "normal" biological population.
Gennaro does not care for Malcolm's pessimism and is still annoyed about the presence of the children. Gennaro, Malcolm, Regis, Grant, Sattler, and the children are taken on a tour of the island in two electrically automated Land Rovers. The tour begins with the hypsilophodontid habitat, but the group is unable to see the animals. But Tim spots an othnielia in the trees. A pre- recorded mating call rouses several hypsilophodontids.
Arnold and Robert Muldoon, the head animal warden, argue with Hammond about the island's many problems. Hammond ignores them, saying "oh balls." The tour passes a group of dilophosaurs—a brightly colored breed that had the park operators had just discovered to be poisonous—and then some triceratops. Lex, Tim's sister, is annoyed that the animals seem so boring and inactive.
While the tour group waits outside the tyrannosaurus paddock, Muldoon ponders how dangerous the park is. No one had any idea that the dilophosaurs could spit venom until one of the handlers was almost blinded. Muldoon is especially wary of the velociraptors, which had killed two construction workers and were adept at breaking out of their cages. On the tour, a live goat is used to lure the tyrannosaurus, which finally appears and eats the helpless animal.
Hammond, sitting in the control room, listens over the radio to the tour group discuss the unpleasant consequences of the t-rex ever escaping. He is annoyed at their negativity. Muldoon walks down to the basement and puts a rocket launcher in his jeep, one of only two gas-powered cars on the island. Tim claims to see a mid-sized raptor running through a field. Because of a developing storm and insufficient protection at the dock, Hammond is forced to call off a supply ship before it unloads the equipment he has ordered.
The tour stops to see Dr. Harding, the island vet, who is treating a sick stegosaurus. Dr. Sattler figures out that the animals are falling ill because they are eating a certain kind of berry. Grant finds the remains of a raptor eggshell, which is odd considering the animals have supposedly been engineered to be unable to reproduce.
Malcolm points out an error in the park's computerized tally of the animals. The tallying system, which had been designed primarily to make sure none of the animals went missing, fails to account for the appearance of any extra animals. Upon Malcolm's suggestion, the computer shows that there are more procompsognathids, maiasaurs, othnielias, hypsilophodontids, and velociraptors than expected. Somehow the animals are breeding.
Grant suggests that, despite the precautions that have been taken, the dinosaurs may be able to breed because Dr. Wu has substituted frog DNA in order to fill gaps in the dinosaur DNA they retrieved from amber. Hungry for dinner, Tim, Lex, and Regis get in one car, while Malcolm and Grant get in the other. Sattler stays with Dr. Harding to tend to the sick stegosaur, and Gennaro joins them so that he can flirt with Sattler. Malcolm is worried because chaos theory predicts that a sudden drastic change will take place on the island soon.
Playing around with some binoculars, Lex spots several small velociraptors on the supply ship that has just left the island. Meanwhile, Nedry jams the computer system and phone lines so that he can sneak into the fertilization room and steal the embryos without setting off the security system. Nedry then takes Muldoon's jeep to drive to the dock. Arnold realizes that Nedry has turned off the security systems, and realizes that the electric fences keeping the animals confined are therefore no longer functioning. Furthermore, Nedry's power cut has disabled the tour cars, leaving the tour group stuck in the now-motionless cars. Muldoon leaves to go get the tour group, but suddenly realizes his jeep is gone.
In this section, Crichton increasingly incorporates elements of science into the book. Graphs, charts, DNA readouts, and lots of scientific background information are included to help explain how dinosaurs could be cloned and what sort of high-tech measures might be employed on an island that tried to contain them. Malcolm's discussions of chaos theory becomes more frequent and detailed, foreshadowing something uncertain and ominous. Although chaos theory implies that the activity of a complex system such as Jurassic Park cannot be predicted, Malcolm says that this very unpredictability implies that something unpredicted will happen.
As the plot gains momentum, the chapter titles begin to alternate in a regular manner. Every other chapter has a descriptive title, such as "The Tour" or "Big Rex," interspersed with several chapters that are titled "Control." In one sense, this name is appropriate because the narrative perspective is switching back and forth between the control room and other areas of the park. The word "control" is also a scientific term, however, referring to a convention of scientific experimentation. If a scientist is studying the effects that a chemical has on wood, for example, he or she will ready two samples of wood and add the chemical to only one of the samples. The untreated sample becomes the control group, and the scientist determines the effects of the chemical by comparing the piece of wood that has been treated to the one that has not. In other words, the control group should remain the same throughout the duration of an experiment.
This idea of the control group can be applied to this section of the novel. The control room of Jurassic Park is supposed to be able to keep the entire island stable and in check. Throughout this section, the narrator's perspective shifts from one part of the park to another. Each time this happens, the reader gains new and unsettling clues: The baby raptor that jumps into Tim's arms looks and behaves just like the animal that attacked Tina, leading us to wonder whether raptors have reached the mainland. Even Dr. Wu becomes nervous about the animals he is creating, as more and more evidence appears indicating that the dinosaurs are breeding. Throughout these revelations the perspective repeatedly returns to the control room, but the control room appears less and less stable each time we return to it. We get glimpses of Muldoon's and Arnold's nervousness that reveal obvious flaws in Hammond's organization of the park. Finally, when Malcolm exposes defects in the park's computer system, the dependability of the entire control room is suddenly called into question. If we consider Jurassic Park one big experiment and the control room representing a supposed force of constancy, just like a scientific control group, by the end of this section we get the sense that the experiment has gone seriously awry.