The evolution of on-screen sci-tech nerds
Brian Dietzen (left) portrays Jimmy Palmer on "NCIS." Simon Pegg portrays Benji Dunn in "Mission: Impossible -- Ghost Protocol."
April 16th, 2012
01:43 PM ET

The evolution of on-screen sci-tech nerds

Almost every crime show has one: the nerd that the “muggles” need to help solve the mystery. Whether hackers or science nerds, they've become a key part of the story.

For years, one of the best-known tech nerds on television was the incredibly awkward yet lovable Marshall Flinkman (Kevin Weisman) on "Alias," the cult favorite ABC spy series. Flash-forward to today's former hacker, the almost-as-awkward Penelope Garcia (Kirsten Vangsness), who often steals scenes on "Criminal Minds," sometimes with boyfriend Kevin Lynch, played by Nicholas Brendon. And there's no forgetting "NCIS" forensic specialist Abby Sciuto (Pauley Perrette), who's not afraid to flaunt her goth style while working in the lab.

Here's a breakdown of on-screen geeks and how they're changing.