A Board of Zoning Adjustment is hereby established in accordance with the provisions of Chapter 89, Missouri Revised Statutes, 1949, regarding the zoning of cities. The word "Board", when used in this Chapter, shall be construed to mean the Board of Zoning Adjustment. The powers and duties of the Board are enumerated in Section 400.290. The Board shall consist of five (5) members who shall be residents appointed by the Mayor and approved by the Board of Aldermen. The term of office of the members of the Board of Zoning Adjustment shall be for five (5) years, excepting that the five (5) members first (1st) appointed shall serve respectively for terms of one (1) year, two (2) years; three (3) years; four (4) years; and five (5) years: thereafter members shall be appointed for terms of five (5) years each. The members shall elect their own Chairman, who shall serve for one (1) year. A member shall serve until his/her successor is duly appointed and qualified. Vacancies shall be filled for the unexpired term only. Members shall be removable for cause by the Mayor and Board of Aldermen upon written charges and after public hearing.