- "By now, we have a complete ecological system, with dozens of species living within their own social groups, without fences, without boundaries, without constraining technology."
- —-John Hammond(src)
In order to create a lost world (in a Jurassic Park sense), you would need an isolated island of right size, the right plants, environment, climate, etc. And that's only just the start.
The concept of a 'Lost World'
- "What we have here is a population of extinct animals artificially introduced into a closed environment, and allowed to evolve all over again. There's never been anything like it in all history."
- —Ian Malcolm(src)
In the mind of popular culture, a 'Lost World' is an isolated area in which animals that were extinct elsewhere in the world (Dinosaurs, Ancient mammals, Pterosaurs, marine reptiles, etc.) are surviving and thriving in that one isolated area. Writers, such as Jules Verne and Sir Arthur Conan Doyle, and film makers have used this concept to make dozens of novels and films, based on that idea. This idea and concept of lost worlds is pretty popular, though it is scientifically unlikely (as explained here). But in the sequel of the Jurassic Park (novel), The Lost World (novel), it has shown that INGEN has been doing been doing the real work of recreating dinosaurs in the island of Isla Sorna or "Site B". They've bred the animals there and nurtured them for a few months before taking them to the park at Isla Nublar. After the Isla Nublar Incident, the staff of Isla Sorna have evacuated, opened the cages, and left the animals to fend for themselves. And years after that, the animals have multiplied and a new ecosystem has developed as a result, with animals either going extinct or developed unusual behaviors to survive.
While it does seem fantastical, there ARE both some real and not so real elements in this idea.
Island Size and Terrain
In the Jurassic Park books, the islands that the dinosaurs were contained in were small islands off the coast of Costa Rica. According to the books, Isla Nublar was 8 miles long and 3 miles at its widest, whereas Isla Sorna is about 50 or 55 square kilometers. While these islands sound big, they're not big enough to support the dinosaurs for very long, especially for large herbivores. The reasoning for that is that the larger the island is, the more food is available to the large animals. In order to support enough large herbivores to feed a population of predators, the island would need to be the size of Connecticut.
Another reasoning for size is for the predators, especially for the large ones. Large predators, like the Tyrannosaurus, would need large amounts of land to support enough numbers of prey to support itself. According to Sarah Harding in the Lost World novel, active predators (like lions) would need a territory at least 10-15 square kilometers per individual predator and that the Isla Sorna from the novel was WAY too small to support the number of Velociraptors and tyrannosaurs that were present on the island.
Another issue would be the terrain of the islands. in the book, Isla Nublar was said to be like a "volcanic upthrusting of rock", a "rugged and craggy" place with forested slopes. For the species of dinosaurs that were the size of elephants and larger, that kind of environment is a terrible, poor habitat for such animals. These sort of species would need large, level open areas to roam. But, smaller species of dinosaurs would make due of this sort of habitat, such as the Procompsognathus, Othnielia, Hypsilophodons, etc.
The movie canon Isla Sorna is larger, but probably not large enough.
It is possible that they were genetically engineered to require less food, though that would only be a temporary solution at best as they bred and multiplied. It is also possible that Dinosaurs, like most reptiles, require less food than mammals, though their bird like characteristics do not aide this thought process.
Dinosaurs lived everywhere in a variety of climates: from deserts to plains to jungles to even polar forests. Isla Sorna only has a southern plain, a non tropical forest and a rainforest. This limited range affects what species could live on the island.
Dinosaurs Released into the Wild
While it seems easy to think that you could just release the dinosaurs and the animals would immediately get along with being wild, it is actually more difficult than it seemed. There were issues that both the predatory dinosaurs and even the herbivorous dinosaurs would face when they're in the wild. The troubles they would face are based on - reasons: One is that these animals were born in captivity and obviously had no older dinosaurs to teach them some of the important behaviors of surviving in the wild. Two is that the world that the animals were brought into was not the world or environment that their ancestors were born into.
As a side note, though some of their behaviors are inherited through their genetic material, that was only half of the behavioral deal. The other half is learning for other members of its species.
There are two issues that herbivores would face in the wild; the first one is eating the right sort of plant and the second is learning to recognize and to avoid predators. Not all species are edible and can make toxins to deter would-be herbivores. While some plants can just make animals sick, there are species that can cause symptoms that can lead to death (such loco weed can cause death to horses and cattle). One good example of dinosaurs suffering from plant toxins in the franchise is the Stegosaurus (from the novel) and the Triceratops (from the film) suffering from the toxins of West Indian lilac berries.
Herbivorous animals that were just released would just eat any plant, even the poisonous, because they are both naive about plants being toxic and they may be too hungry to care or notice. This is a sort of problem that ranchers and farmers face when their livestock live in large pastures in the open range. One way this could be avoided is to before releasing them, the animals should be given high quality or quantity of food and when they are released, they will just experiment with the various plant species they find and will make a mental list of plants that were good to eat and those to avoid.
Dinosaurs and Indigenous Flora/Fauna
While Isla Sorna may have been an isolated island, there would indeed have been native wildlife. Caimans, Birds and smaller mainland mammals like Monkeys or Opossums. These creatures would have had to contend with the Dinosaurs and possibly conflict. Smaller Dinosaur species would have had to deal with direct competition and predation, and mammals may have behaved in their prehistoric role as egg thieves. The bird species would have also competed with any smaller Pterosaurs.
Along with relations between the dinosaurs and the indigenous flora and fauna, another thought of concern is the relations between the different dinosaur species on the island. But this is not really the case, that is because that these dinosaurs have developed in different places, times, and in response to different sorts of predators and preys. In the films, all the different dinosaur species have coexisted perfectly and that all the species have survived. In the Lost World novel, however, it was mentioned that some species might have went extinct when they were left behind.
One of the issues that the dinosaurs would have to deal with each other is responding to predators. Some herbivores could've been physically adapted to defend themselves from certain predators. For example, Stegosaurus seems to be physically built for defeating themselves against large theropods that lived when it was around (such as Allosaurus and Ceratosaurus). This seems to be evident due its only individual defense is its thagomizer (tail spikes) and bones underneath the skin of its throat, which acts like chain-mail. Along with no being a fast runner, it's definitely safe to conclude that Stegosaurus could stand on its own against large to medium-sized theropods, though it might not be able defend itself against smaller, pack hunting theropods (although there is no evidence for any non-avian dinosaur hunting in packs, it is possible that some did). A real-life example of animals not being able to resist against new predators is the numbat, a insectivorous marsupial that is native to Australia. While this animal has adapted to native predators and the dingo, it is not faring well against introduced predators, such as cats and foxes.
Another issue that the dinosaurs would face is the species of predators competing with one another. Around the world, there are native predators that are becoming misplaced by introduced predators. For example, foxes and cats are misplacing quolls on Australia, alligators are being displaced by burmese pythons in Florida, and (while still in debate) the dingo supposedly out-competed the Tasmanian Tiger or Thylacine, thus wiping the marsupial off of mainland Australia thousands of years ago. With this in mind, some of the theropods would've been out-competed by social (pack-hunting), larger, or more aggressive theropods.
Another issue that the dinosaurs would face is an issue that most people wouldn't think about and that is grazing/browsing competition between herbivores. There are real-life examples of this being a problem. One is that is Australia, rabbits compete against the wombats and it is actually threatening the futures of the wombat species. On the same continent, feral goats are competing with rock wallabies and are driving them to extinction.
The ecology of animals relates to how species interact with other organisms and their natural enviroments, theropods will compete with other predatory dinosaurs much like modern day lions; hyenas; bears and wolves. Tyrannosaurus rex would've likely competed for food sources with other carnivores such as Troodon and Nanotyrannus.
Clones are generally made from the same DNA source, and thus end up being exact copies on one another. This leads into a genetic devastation in just a few generations, unless multiple DNA sources were used in cloning them, though due to the odds of getting two of the same species this is unlikely.