In the movie Jurassic Park, a theme park promoter (played by the great actor Richard Attenborough) working with some scientists, figure out how to create real dinosaurs from DNA preserved in mosquitos, which are further preserved in amber. The concept was created by the physician and fiction writer Michael Crichton. Crichton had recently learned about the concept of Chaos Theory, without actually really understanding what it is, and his "mathematician" character played by Jeff Goldblum, questions whether such a thing is a good idea or not, even if it is possible. There are many, many things wrong with the idea of Jurassic Park, and it is probably impossible.
1: They got the DNA from the gut of mosquitos, which had bitten the dinosaur shortly before they themselves were trapped in amber. Mosquitos and other things were trapped in amber from that long ago and have survived in some sense. But what's still there is their exoskeleton and not much else. The chemical processes of digestion continue at some level even after the critter has died. Eventually the acids and such are used up and only things which are harder to digest survive, but within a few hours after the mosquito ate it, the dinosaur DNA is pretty much digested, whether the mosquito is still alive or not.
2: Recent studies have found that DNA exposed to the environment and not actively being maintained by cell nuclei have a half-life of around 521 years. That is, after 521 years, the odds of being able to extract a valid DNA sequence is about 50%. After 1042 years, it's 25%. After 66 million years it's about 0.0000015%. So close to zero as to make no difference.
When Crichton wrote his book, the understanding of DNA sequencing was much less mature than it is today, but he was aware of the basic facts of these statistics.
3: When they found errors in the DNA in the book/movie, they were able to patch it using the DNA from frogs. Weird choice. The movie itself recognizes that birds are the dinosaur's nearest living cousins. It is far from possible to do anything like this sort of DNA patching today, but it may eventually turn out to be possible. But at that point, you're more or less making a new creature from scratch.
The reason they made this choice is because it's known that some frog species, when there are only females and no males, are able to transform one of their number into something sufficiently male as to be able to reproduce. It is quite well known that fish do this and the effect has been seen by tropical fish hobbyists.
4: The horrible whiney Jeff Goldblum character is actually toned down quite a bit from his prototype in the book. He clearly doesn't understand what Chaos Theory actually is or anything about its statistics. His argument is basically that we shouldn't ever open Pandora's box, because Chaos Theory is in charge. But in this example, what's really in charge is evolution--accelerated by an opportunistic thief misbehaving. Evolution requires astronomical numbers of individuals and years to do its magic. There are only a few handfuls of the most numerous species on the island operating for a decade or so at most. Not much is going to happen. The argument he should be making is about things like bioweapons and the waste products of nuclear fission. These things have already been produced in astronomical amounts and an incident like the one in the story will cause them to get out.
(I never liked Jeff Goldblum very much. His best role was in Into the Night, and he did a good job as a backstabbing baddie in Silverado. Jurassic Park and Independence Day cemented his place as a jerk who the director imagines can be plausible as a scientist. Actual scientists tend to disagree on the plausible as scientist part.)
(I first saw Jurassic Park in a theater with a bunch of computer hackers. When she says "Oh, this is unix, I know this", we all did a snort take. First of all, it's not unix, it's some goofy graphical shell that somebody implemented on top of unix on SGI hardware. the stuff she needs to know in order to turn the park's safety systems back on are in that goofy graphical shell and highly specific to that application. I'm sure an actual hacker put in that position could figure it out, but unix has nothing to do with it.)
