1. Unless otherwise provided in the articles of incorporation or bylaws of the corporation, vacancies on the board and newly created directorships resulting from any increase in the number of directors to constitute the board of directors may be filled by a majority of the directors then in office, although less than a quorum, or by a sole remaining director, until the next election of directors by the shareholders of the corporation; except that, if shareholders elect directors by class pursuant to section 351.315, a director elected by the board pursuant to this section to fill a vacancy or to a newly created directorship need not be presented for election by shareholders until the class to which the director has been so elected by the board is presented for election by the shareholders.

2. Whenever the holders of any class or classes of stock or series thereof are entitled to elect one or more directors by the articles of incorporation, vacancies and newly created directorships with respect to such class or classes or series may be filled by a majority of the directors elected by such class or classes or series thereof then in office.