Section 4.7.  Powers and duties of mayor; mayor pro tem.
   (a)   The mayor shall preside all meetings of the council.  He shall be a full voting member of the council but shall have no veto power.  He shall be the chief executive officer of the city insofar as required by law and for all ceremonial purposes.  He shall be the conservator of the peace and shall have the powers conferred by law upon sheriffs in times of emergency to suppress disorder, preserve the public peace and health and safety of persons and property and have other emergency powers as permitted by law.  He shall authenticate by signature such instruments as may be required under provisions of law.  He shall do all acts required of him by law.
   (b)    The mayor pro tem shall act in place of the mayor in the absence or disability of the mayor.  He shall succeed to the office of mayor in the case of a vacancy in that office, thereby creating a vacancy in the office of mayor pro tem.  The council shall fill any vacancy in the office of mayor pro tem.  Until such vacancy is filled, the senior member of the council from the standpoint of continuous service shall act as mayor pro tem.  Between persons of equal seniority, the person who received the highest number of votes at the time of his last election shall act.