The members of the board of trustees, city clerk, city treasurer, city tax and license collector, city assessor, city recorder and the trustees of the school districts in office at the time of the approval of this Charter by the legislature shall severally continue to hold office and discharge their respective duties until the election and qualification of the commission, auditor, treasurer, city attorney and members of the board of education respectively first elected under this Charter. The term of office of all other officers in office at the time this Charter shall take effect shall cease and terminate when the commission first elected hereunder shall by resolution so declare.