evolve vs occur

evolve

verb
  • To come into being; develop. 

  • To change; transform. 

  • Of a population, to acquire or develop (a trait) in the process of biological evolution. 

  • To give off (gas, such as oxygen or carbon dioxide during a reaction). 

  • To move in regular procession through a system. 

  • Of a trait, to develop within a population via biological evolution. 

  • Of a population, to change genetic composition over successive generations through the process of evolution. 

  • To cause something to change or transform. 

occur

verb
  • To come or be presented to the mind; to suggest itself. 

  • To happen or take place. 

  • To present or offer itself. 

  • To be present or found. 

How often have the words evolve and occur occurred in a corpus of books? (source: Google Ngram Viewer )