Trivia: "Evolution" was originally written as a serious sci-fi thriller by writer Don Jakoby. When Ivan Reitman signed on to direct, he felt the concept would make for a good ensemble comedy, similar to his film "Ghostbusters." Jakoby actually liked the idea of reworking the film into a comedy so much, he stayed with the project and assisted in re-writes.
Trivia: During the shoot in Arizona, Dan Aykroyd would have fun by randomly show up at the houses of locals to hang out and have a cup of coffee. He also helped out at local businesses.