The civil service commission shall consist of 4 members appointed by the governor, not more than 2 of whom shall be members of the same political party. The term of office of each member shall be 8 years, except that of members first appointed 1 each shall be appointed for terms of 2, 4, 6 and 8 years. A member appointed to fill a vacancy occurring other than by expiration of a term shall be appointed for the unexpired term. The commission shall elect from its members such officers as it deems advisable. A majority of the commission members shall be required to constitute a quorum.