Upon the initial appointment of members to the municipal planning commission, the mayor shall designate one member of the municipal planning commission to serve for a period of one year, two (2) members to serve for a period of two (2) years, and two (2) members to serve for a period of three (3) years. All subsequent appointments of members shall be for a three (3) year term, and until their successors are appointed and qualified. (1985 Code § 1-39)