"Evolution" is a movie that wants badly to be "Ghostbusters," but it isn't. So, while it is an amusing movie, well worth the price of matinee admission, it can't help but suffer in comparison.

Both films are directed by Ivan Reitman, who hasn't made a really good film since 1990's "Kindergarten Cop." So, perhaps he can be forgiven for so shamelessly ripping off his 1984 blockbuster. At least he does a better job of it this time than he did with "Ghostbusters II" in 1989.

"Evolution" stars David Duchovny as Ira Kane, a scientist exiled to a community college in Arizona, where he passes out easy A's or, at the worst, C minuses. It is little surprise that Ira comes across as a laid-back Fox Mulder with the serial numbers filed off.

And, of course, there are one or two jokes aimed directly at Duchovny's "X-Files" roots. This is an alien invasion movie, after all.

But it's all OK. In fact, Ira reminds me of just how much I missed Agent Mulder's humorous side during the past "X-Files" season.

Ira's colleague at the college is Harry Block, played by Orlando Jones.

Jones' best-known role to date is the clueless pitchman in a popular series of 7-Up commercials, so it's nice to see him get the chance here to show what he can do, which is steal most of the scenes he is in.

Harry is a geology teacher and the winningest women's volleyball coach in school history.

And, thanks to a form he filled out on the Internet, he is also the local representative for the U.S. Geological Survey.

So, when a meteorite crashes nearby, Harry gets the call to check it out, and he takes Ira along just in case any real science needs to be done.

Of course, it turns out the meteorite is teeming with microscopic life — otherwise this wouldn't be much of a movie, now would it?

But it isn't just any old life. It's evolving at an accelerated rate, gaining complexity in mere hours that it took life on Earth millions of years to achieve.

Obviously, this is big news, and Ira and Harry have visions of Nobels dancing in their heads.

But before they can make their move, word of the discovery leaks out, and suddenly the impact site is crawling with military brass and government bureaucrats, all of whom are up to no good (or is that redundant?).

If Duchovny is playing essentially the Bill Murray character from "Ghostbusters," then somebody has to take on Sigourney Weaver's love-interest role. That somebody is Julianne Moore ("Hannibal"), who plays klutzy Centers for Disease Control representative Allison Reed.

Although Ira and Allison start out on opposite sides, you know they're meant to be together. After all, we've seen this movie before.

Rounding out the core cast is Seann William Scott ("American Pie"), who plays a dimwitted would-be fireman who discovers the meteorite and winds up helping Ira and Harry track down the rapidly evolving extraterrestrials.

And, speaking of "Ghostbusters," Dan Aykroyd shows up to do his rapid-fire dialog routine as the governor of Arizona.

There is some funny stuff going on in "Evolution," especially the chase through the shopping mall and Harry's line, "There's always time for lubricant," which is hilarious in its context. But there are also a lot of missed opportunities. Sometimes you're expecting a joke, and it never shows up. "Evolution" is more of a clever movie than a funny ha-ha movie. It's just not as clever as it thinks it is.

Or maybe it's just because we've seen it all already?

That said, "Evolution" does at least outdo "Ghostbusters" when it comes to special effects. But then it's had 17 years of technological advancements on which to build.

Visual effects supervisor Phil Tippett, whose resume includes the original "Star Wars" trilogy and the first "Jurassic Park" movie, gives us some truly amazing creatures to look at — everything from alien slugs to bizarre insects to pterodactyl-like birds.

So, despite its flaws, the balance sheet for "Evolution" comes out in the black.

Plus, it's hard not to like a movie where everyone involved in making it seems to have had such a good time.