1. The following officers shall be elected by the qualified voters of the city, and shall hold office for the term of two years, except as otherwise provided in this section, and until their successors are elected and qualified, to wit: mayor and board of aldermen. The board of aldermen may provide by ordinance, after the approval of a majority of the voters voting at an election at which the issue is submitted, for the appointment of a collector and for the appointment of a chief of police, who shall perform all duties required of the marshal by law, and any other police officers found by the board of aldermen to be necessary for the good government of the city. The marshal or chief of police shall be twenty-one years of age or older. If the board of aldermen does not provide for the appointment of a chief of police and collector as provided by this section, a city marshal, who shall be twenty-one years of age or older, and collector shall be elected, and the board of aldermen may provide by ordinance that the same person may be elected marshal and collector, at the same election, and hold both offices and the board of aldermen may provide by ordinance for the election of city assessor, city attorney, city clerk and street commissioner, who shall hold their respective offices for a term of two years and until their successors shall be elected or appointed and qualified, except that the term of the city marshal shall be four years.

2. The board of aldermen may provide by ordinance, after the approval of a majority of the voters voting thereon at the next municipal election at which the issue is submitted, that the term of the collector shall be four years and the term of the mayor shall be two, three, or four years. Any person elected as collector after the passage of such an ordinance shall serve for a term of four years and until his successor is elected and qualified. Any person elected as mayor after the passage of such ordinance shall serve for a term of two, three, or four years, as provided, and until his successor is elected and qualified.

3. The board of aldermen may provide by ordinance that the term of the board of aldermen shall be four years. Such ordinance shall be submitted by the board to the voters of the city and shall take effect only upon the approval of a majority of the voters voting at an election at which the issue is submitted. Any person elected to the board of aldermen after the passage of such an ordinance shall serve for a term of four years and until his successor is elected and qualified.