This one stars David Duchovny as Ira Kane, a science professor at a small Arizona community college. He and his friend Harry Block (Orlando Jones), a geology prof at the same school, are brought in to investigate a large asteroid that has fallen to earth and been found by a fireman-in-training named Wayne (Seann William Scott). They take samples of a strange liquid that seeps from the rock. When examined under a microscope, it becomes clear that the stuff is rapidly evolving from single-cell organisms to multi-celled ones. Back at the crash site, strange creatures start forming and escaping into the community. All of them are slimy, most are quite nasty. The government eventually learns of Ira and Harry's discovery and comes in to take over. One of the people they place in charge is a CDC scientist named Allison Reed (Julianne Moore). She's beautiful and brilliant, but also quite klutzy. Kane hates her almost as much as he wants her.

As the days wear on, the creatures begin evolving into more and more complex creations, including a giant flying lizard that attacks a shopping mall. Harry and Ira think they can figure out a way to kill the creatures but the government won't allow them to be part of the project. The Arizona governor (Dan Aykroyd) authorizes the use of napalm to wipe the aliens out. Exposing them to fire, it turns out, is not a good idea. There is a better (and most unusual) way of eradicating them from Earth. Allison eventually agrees to help Harry and Ira execute the idea. The method they use is one of the funniest things about the movie; you have to love it when a totally innocuous substance is used to annihilate an alien species.

Evolution was directed by Ivan Reitman, and I am already hearing some critics gripe that this is little more than a remake of Ghostbusters, except with aliens. Yes, there are similarities between the two. I also think that it sells this movie a bit short to accuse it of being a ripoff. Movies have been recycling formulas for a long time. Ghostbusters itself recycled comedies like the Bob Hope flick The Ghost Breakers and Abbott & Costello's Hold That Ghost. A formula can always work again if its done well, which I think it is here.

Julianne Moore and David Duchovny help Orlando Jones get a bug out of his butt in Evolution

A good cast is part of the reason it works. David Duchovny does a sly parody of his "X-Files" character. At one point, someone suggests calling in the government, and Duchovny's character says: "No government. I know those people." He teams up surprisingly well with Orlando Jones (most people know him as "the 7-Up guy" although I think his star is on the rise). Jones has a way of generating laughs with just a look or a throwaway phrase. Early on, an alien bug enters his body, requiring a surgical procedure to remove it. The scene is hilarious because Jones amps up the inherent humiliation of the scene. Then there's Julianne Moore, just about the last actress you'd expect to see in a goofy comedy like this. She looks like she's having a ball playing up the contrast between Allison's stunning beauty and her utter lack of grace. When the cast appears to be having so much fun making a movie, the feeling is contagious to the audience.

Reitman knows how to work a scene as well. With an able cast, he's free to make the alien scenes more outrageous. I especially liked the scene in the shopping mall, in which the flying lizard carries a shoplifter around in its teeth. (If more malls had this kind of security, retail theft would go into a serious decline.) The movie's creatures seem to be part of the story rather than just an excuse for special effects. The director takes them seriously, as do the actors, without sacrificing the comedic elements they bring. If the earth ever is invaded by aliens, I hope the attack is as wacky/horrific as it is in this film.

If there is a flaw in Evolution, it would be that there's no greater scheme to things. We never learn where the aliens are from, or what they want to do on Earth. Granted, they came here by accident but some kind of larger purpose might have been nice. The screenplay is reported to have originally been a much darker, dramatic sci-fi story of fast-evolving aliens. Perhaps some of the background was tempered once the filmmakers decided to do a comedy instead.

Even if the story is a bit slight, I enjoyed the movie on its own terms. It's early summer - a time for easygoing films that offer lots of fun and not much that taxes the brain. I walk into a picture like Evolution in that spirit, and this time I was not disappointed. There are big laughs here, some good performances, some great effects. It's a good, goofy time at the movies.

( out of four)

Evolution is rated PG-13 for crude and sexual humor, and for sci-fi action. The running time is 1 hour and 43 minutes.