call up vs take on

call up

verb
  • To summon (someone) to report for military service. 

  • To select e.g. to a sports squad. 

  • To retrieve from personal or computer memory. 

  • To call on the telephone. 

noun
  • An order to report for military service. 

take on

verb
  • To acquire, bring in, or introduce. 

  • To assume or take responsibility for. 

  • To (attempt to) dribble round (an opposition player). 

  • To catch on, do well; to become popular. 

  • To obtain the services of (a person) in exchange for remuneration; to give someone a job. 

  • To begin to have or exhibit. 

  • To attempt to fight, compete with, or engage with. 

  • To grieve or be concerned (about something or someone). 

How often have the words call up and take on occurred in a corpus of books? (source: Google Ngram Viewer )