I swear Williams got the Jaws theme from Star Trek
Check out the original Star Trek episode "Journey to Babel", the one where we
first meet Spock's parents.
Listen to the music in the scenes where the Orion spy ship is attacking the
Enterprise. As it approaches, the music sounds an awful lot like the Jaws
Here Comes the Shark for a Snack theme.
Williams did the theme for Lost in Space (he was credited as Johnny Williams
back then), which came out around the same time in the 1960s, so it is quite
possible he was "inspired" by that music from Star Trek when he wrote the
famous Ba Dum bit for Jaws.
I'm just sayin'....