The job: Samuel J. Morse was awarded a U.S. patent for the first telegraph in 1840. By transmitting electrical signals over wire, the telegraph allowed for instantaneous long-distance communication. And by using a universal code that Morse developed, telegraph operators -- or telegraphers -- were able to send and decode complex messages through a series of dots and dashes representing each letter of the English alphabet.
Killed by: The invention and adoption of the telephone. Alexander Graham Bell patented the telephone in 1876 and made the first telephone call later that same year. By 1940, the telephone had become ubiquitous in American homes. The telegraph steadily declined as the telephone gained in popularity, and the telegrapher profession went with it. On January 27, 2006, the telegraph era officially ended in the U.S., when Western Union disconnected its telegraph messaging service and sent its last message.