The central theme in the films is that “life finds a way” to break through barriers, boundaries, and sometimes destructively. Human intervention and control is seen as something that is an illusion as nature/life will find a way to establish balance or restore order over restraint. This theory is constantly promoted by Dr. Ian Malcolm.
Malcolm, a guest on a tour through Jurassic Park, consistently ranted about the inevitable failure of the animal preserve/theme park. He saw the reliance on computer automation and genetics to control and contain the animals as a doomed prospect because the adaptability of life always allowed it to flourish and defy logic.
InGen had devised a way to control the population of their dinosaurs in two ways. The first way was to manipulate all of the animals genetically by making them female. Geneticists denied the extra hormone that would enable the fetus to become male, this–in theory–would prevent any unauthorized breeding in Jurassic Park and keep an easily sustainable and stable population that InGen staff could monitor. During the Isla Nublar incident however, Dr. Alan Grant and Dr. John Hammond‘s grandchildren discovered physical evidence of breeding dinosaurs in the park when they stumbled upon an abandoned Velociraptor nest. Grant realized that the animals were capable of breeding because the gender controlled introduced by Jurassic Park geneticists was neutralized by the frog DNA they implemented to fill the holes in the DNA structure. West African frogs were known for their ability to alter their sex in an environment that merely had one sex, thus enabling breeding and species continuation.
Dr. Henry Wu, Chief Geneticist of Jurassic Park, inserted a flaw in the dinosaurs as a secondary fall back that would ensure InGen’s grasp on their dinosaurs and promote safety. Wu made sure all of Jurassic Park’s dinosaurs were incapable of producing lysine, an essential amino acid, on their own. They needed to be provided with lysine in their food otherwise they would slip into comas die within a week. Dr. Sarah Harding, during the expedition to Isla Sorna a few years later, discovered that the contingency failed because the herbivores learned to feed on lysine rich plants and the carnivores survived because they acquired their lysine from their prey.