LOS ANGELES — In “Jurassic World,” scientists create a living theme park attraction called Indominus rex by splicing the DNA of two very different dinosaurs. They are ecstatic. Behold! The glorious future, a ticket-selling machine.

But there are naysayers. Madness! This Franken-beast monster may draw crowds, but it is not natural. You cannot be two things at once.

The director and a writer of “Jurassic World,” Colin Trevorrow, and the film’s heavily involved executive producer, Steven Spielberg, are most definitely in the first camp: If not with Indominus, then at least with their science-fiction thriller. “Jurassic World,” even with a production budget of $150 million, is in many ways an experiment: Can a greenhorn art-house director (Trevorrow, 38) meld his filmmaking ideas with those of a cultural giant (Spielberg, 68) to successfully dust off a 1990s-era movie series?

Trevorrow is hardly the first unseasoned filmmaker to be given the keys to a major franchise. Others include Marc Webb (“The Amazing Spider-Man”), Joseph Kosinski (“Tron: Legacy”) and Josh Trank (the coming “Fantastic Four”). But it is relatively rare for the originator of a movie series to remain so involved in a rejuvenation effort. Spielberg did not visit the “Jurassic World” sets, but he approved the script, watched footage daily and emailed and texted suggestions.

“I remember that first two-hour meeting with Steven, when I had to stop being a fan and think about work,” Trevorrow recalled. “I was like, ‘Look, if “Jurassic Park 4” fails, you continue on being a legend. I’m finished.’”

Trevorrow’s only previous experience as a feature film director came in 2012 from “Safety Not Guaranteed,” a well-reviewed comedic drama. Budget: $750,000.

“Jurassic World” will almost certainly be a success when it arrives Friday, at least from a financial perspective. Surveys that track audience interest indicate that its distributor, Universal Pictures, has whipped up significant excitement; opening weekend ticket sales could reach $100 million. The first three films, the first two directed by Spielberg and the third led by Joe Johnston, an experienced studio filmmaker, took in $3 billion globally, after adjusting for inflation.

But reinvigoration is the true goal, and whether “Jurassic World” will be received by audiences (and critics) in a way that confidently propels the series forward is still an unknown.

In a departure from the previous films, the island theme park is now fully operational. There is a baby triceratops ride for children, a domed pterodactyl exhibit and a SeaWorld-style lagoon show starring a fearsome Mosasaurus. Still, attendance is sagging, and the park’s manager, played by Bryce Dallas Howard, has turned to Indominus rex.

Things do not go as planned. But in a twist, a sexy animal expert (Chris Pratt) reluctantly uses his trained velociraptors to take on the renegade reptile.

Spielberg, who has made a point to mentor budding directors (J.J. Abrams most prominently), said in an email that he was impressed by Trevorrow’s confidence, especially with “Safety Not Guaranteed.”

Trevorrow was hired in March 2013 without his having seen the script. He disliked what he read. “I didn’t understand what it was about,” he said. So, along with his writing partner, Derek Connolly, Trevorrow cranked out a new draft built around three bedrock ideas from Spielberg: The park was open; the raptors could be trained; and a synthetic dinosaur had been created. Among other Spielbergian parameters, there had to be children involved.

Spielberg was pleased with the new script, so pleased, in fact, that he hit the brakes. “The studio was happy, but until Steven says, ‘Yeah, go shoot this movie,’ nothing is happening,” Trevorrow said. “He said, ‘Let’s take another year, because if we do it right this could be really special.’”

Along with big action moments provided by marauding dinosaurs, Trevorrow wanted “Jurassic World” to have elements of romantic adventure and screwball comedy. “I wanted to make something that is funny and warm and emotional and romantic while also being scary and intense and dark,” he said. “A movie doesn’t have to be just one thing.”

That may be Trevorrow’s confidence talking, or maybe his lack of Hollywood-weary cynicism. As studios seek to attract ticket buyers overseas, event movies are becoming stripped of their nuance.

But Trevorrow misses more artisanal movies from his 1980s childhood, like “Romancing the Stone” and “Indiana Jones and the Temple of Doom,” both of which added a gender war element to the action. “We haven’t seen that in a long time,” he said. “Those kinds of male-female dynamics are things that are universal. Men and women don’t understand each other, and I don’t find that in any way to be a trope.”