There shall be a Planning Commission, which shall consist of seven (7) members, five (5) of whom shall be appointed by the Council, and none of said five (5) appointed members shall hold any other elective public office. The sixth member shall be elected by the Council from its membership for his term as Councilman. The Manager shall serve as an ex officio member. The Commission shall elect its Chairman from among the appointive members. The term of the appointive members shall be five (5) years, except that, of the five (5) members first appointed, one (1) shall be appointed for a term of one (1)year, one (1) for two (2) years, one (1) for three (3) years and one (1) for four (4) years. Any vacancy during the unexpired term of an appointive or elective member shall be filled by the Council for the remainder of the term.