The Commission shall consist of five (5) members including the Mayor who shall have no vote except in case of a tie. They shall be appointed by the Mayor, with approval by the Council, to serve, one for one year, one for two years, one for three years and one for four years or until their successors are appointed and assume office. Thereafter one shall be appointed each year in like manner to serve for four years or until their successors are appointed and assume office. Vacancies shall be filled by similar appointment for unexpired terms.