TONIGHT'S MUST-SEE

"Jaws" (1975), 5 p.m., AMC or Shark Week specials, 3 p.m. Discovery Channel. It was "Jaws" that launched our national obsession with sharks. A young director (Steven Spielberg) and a veteran composer (John Williams) created vivid images. And it is Discovery that propels the obsession each year. Tonight's films have "Prowling Sharks in the Mediterranean" at 4 p.m., "Jaws of the Pacific" at 5, a "Mythbusters" special at 6 and "American Shark" at 8. Then "Jaws of the Pacific" and "Mythbusters" rerun.

"Baby Borrowers," conclusion, 8 p.m., NBC. Last week's episode (rerunning at 7 p.m.) had the teens become temporary parents of other teens. Now the final twist has them care for the elderly, with varying disabilities. A follow-up tells what happened to the couples when the experiment ended.

OF NOTE

"Shear Genius," 7 p.m., Bravo. When "Charlie's Angels" debuted in 1976, even its hairstyles became famous. Tonight, contestants will try to re-create them with two original Angels (Jaclyn Smith and Kate Jackson) watching.

"Click & Clack's As the Wrench Turns," 8 p.m., PBS. This cartoon for grown-ups has the brothers facing a crisis: A new garage has opened, featuring good-looking mechanics and a cappuccino bar.

"Criminal Minds," 8 p.m., CBS. The new boss (Joe Mantegna) opens up a case from his past in this rerun. The team starts working on murders committed more than 20 years ago.

"So You Think You Can Dance," 8 p.m., Fox. Last week's results show was rough, with the terrific Will and Twitch in the bottom. One was ousted. That hour — with performances by L.L. Cool J and the Los Angeles Ballet — reruns at 7. The final six perform at 8.

"Nova ScienceNow," 9 p.m., PBS. In 1962, scientists were impressed by the Nebraska discovery of mammoths — their 12-foot tusks locked together. They apparently became stuck during a fight. This film uses modern science to learn more.