Except as otherwise provided in this constitution, all officers filling any office by election or appointment shall continue to exercise their powers and duties until their offices shall have been abolished or their successors selected and qualified in accordance with this constitution or the laws enacted pursuant thereto.

     No provision of this constitution, or of law or of executive order authorized by this constitution shall shorten the term of any person elected to state office at a statewide election on or prior to the date on which this constitution is submitted to a vote. In the event the duties of any such officers shall not have been abolished or incorporated into one or more of the principal departments at the expiration of his term, such officer shall continue to serve until his duties are so incorporated or abolished.