One problem is that we really do not know very much about dinosaurs, especially live ones, and especially genetically tweaked live ones. A bigger problem is that we keep ignoring what we do know about humans. Over and over again we see that humans are petty, greedy for both money and power, and very unclear about the line between optimism and hubris. Maybe someday we will figure out a genetic tweak to adjust that problem, but for the time being we are stuck with it, which is bad for us, but pretty good for movies. It gives us just enough of a framework for the storyline without interfering with the real purpose of the movie, which is, let’s face it, seeing people get chased by dinosaurs. And that is what happens, all right. A lot of people get chased by a lot of dinosaurs, and it is exciting and cool and a lot of fun.

Remember what Jeff Goldblum said in the first “Jurassic Park” movie?   The man behind the idea of taking dino DNA from amber and re-creating creatures who died out 70 million years ago compared the delays to the opening of Disneyland. Yes, Goldblum’s expert in chaos theory replied, but “if The Pirates of the Caribbean breaks down, the pirates don’t eat the tourists.” Despite the devastation inflicted on the planet in the first three movies (remember that optimism/hubris problem), things have moved on, and Jurassic World is now a flourishing theme park with 20,000 visitors at a time. Indeed, it is all a little been there-done that, the dinosaurs so tame there is actually a petting zoo portion of the park, where children can ride on triceratops. Investors want better returns and Claire (Bryce Dallas Howard), the director of the park, is under a lot of pressure to create more “wow factor.” The dinosaurs are no more exotic than the elephant at the zoo. “We want to be thrilled.”

She and the eighth richest man on the planet, the CEO of the company who owns Jurassic World, have decided the best way to do that is to spend $28 million to create a bigger, smarter, angrier dinosaur made up of all the scariest parts of all the other dinos. You know, Frankensaurus. What could possibly go wrong?

Making up the rest of the human cast are some disposable red shirt types whose primary job is to be clawed and/or eaten, as well as Claire’s two nephews (Nick Robinson and Ty Simpkins) and a couple of Navy vets who have been working on an experimental program to see whether raptors can be trained, Owen (Chris Pratt) and Barry (Omar Sy). There’s also a computer guy (Jake Johnson), a scientist (B.D. Wong), and the grand prize winner of the really bad idea competition, a military type (Vincent D’Onofrio) who wants to weaponize the dinosaurs and use them in combat.

There’s a terrific opening, as powerful talons crack through egg shells, terrifying literally from the very first second. Then there’s a clever twist to remind us that we are here to have PG-13-style fun. We have about an hour to familiarize us with the characters, the layout, and the vulnerabilities, oh, yes, and the characters. And the rest is people getting chased by dinosaurs in a variety of extremely intense and exciting and creative ways, and in many different locations. The 3D effects are jump-out-at-you scary. Howard makes the best of a thankless part.  Claire starts out as a caricature of a control freak, dressed all in Olivia Pope white, with perfectly groomed, razor-styled red hair.  We know how inhuman she is because she barely remembers the names of her nephews and refers to the dinosaurs briskly as “assets.” And she once went on a date with a print-out of the schedule.  It is fun to see her become more messy and human, though ridiculous that she never takes off her high heels and gets the vapors over seeing a Real Man do Manly things.

The real wow factor in the film is Pratt, who exhibits a natural Indiana Jones-style, all-American heroism. Not many actors can hold their own against a genetically modified T-Rex the size of Godzilla, but Pratt, whether dinosaur whispering or racing his motorcycle, is an old-school hero. Even if we don’t believe there is any chemistry between his character and Howard’s, his quiet confidence and skill are as much fun as all the CGI-asauruses.

Parents should know that this film includes very intense peril and violence involving big, scary creatures with lots of teeth, many characters (human and animal) injured and killed, some graphic and disturbing images, brief strong language, brief sexual reference, discussion of parental divorce.

Family discussion: Why did things go so wrong? Whose fault was it? How did the relationship of the brothers change and why?

If you like this, try: the earlier “Jurassic Park” movies and “Walking With Dinosaurs”