A meteorite crashes in the Arizona desert and is investigated by scientific foul-ups Ira Kane and Harry Block. They discover that the rock is covered with single-celled organisms that rapidly evolve into other, more sophisticated, more dangerous lifeforms. The government send in the army and epidemiologist Allison Reed, but the alien life spills out across the state, perhaps threatening the world...
Evolution applies to the science fiction film the mutating formula that Ivan Reitman wrought a decade and a half ago on the horror movie with Ghostbusters. The plot is built on a premise strong enough to be played straight, and the special effects deliver a couple of real scares, but the script and performances are consistently light-hearted, with detours into over-the-top, knockabout comedy.
Like every other funny movie these days, it features several protracted bouts of anal probery first on the face-pulling Orlando Jones (far less annoying here than in his previous film, Say It Isn't So), and then, in a 'payback' sequence (that jabs at the end of Independence Day) on a giant alien CGI blob creature left over from the old Quatermass movies. Just to keep things ticking over, there are also fart, fat, lechery and sleaze jokes, as well as Ghostbusters' cast comedians in the leads, and a bulky Dan Aykroyd as the governor of Arizona but Evolution goes down the Airplane! route by asking usually serious actors to make fun of themselves.
As a disgraced government scientist latching on to a discovery that could see him make it back to the big time, David Duchovny doesn't so much send up his po-faced Agent Mulder persona, as re-use the throwaway, witty tone perfected on The X Files in its occasional, welcome comedy episodes. Julianne Moore, not a natural comedienne, strides into the film with her tough pro heroine credentials from The Lost World and Hannibal, and promptly does a pratfall that marks out her character as a ditz. The gag wears thin after the sixth or seventh time, and too many of the supporting cast are also stuck with the same business of trotting out their one joke every time they appear. But there are enough smart lines and visual bits to keep the chuckles coming.
The film is always engaging, often hilarious and sometimes surprisingly scary. The alien lifeforms are imaginatively designed (especially during one set-piece in which a prehistoric alien wreaks shopping mall havoc), and boast a subtly repulsive look that makes them credibly otherworldly, prompting an instinctive need to squash them like bugs. The super-evolving idea is clever, and might have made for a good, serious Outer Limits episode; there's a great chill as toothy insectile or reptilian creatures are nudged out of the way by vicious, but smarter, tool-using primates.
Unfortunately, at a major plot and evolutionary juncture, the movie opts to get dumber rather than cleverer. The finale, all too obviously inspired by Ghostbusters' marshmallow man, goes for gooey jokes and literal flatulence, when a less comical film might have ventured into more interesting, more terrifying regions.
As a rare 'original' summer movie, this is extremely welcome. Likeable despite its silliness, Evolution delivers a solid entertainment package. Note of caution: the monster stuff might be too intense for the more sensitive moviegoer.