The councilmembers in office at the time this charter is adopted shall continue in office, each until the end of the member’s term of office as fixed by the charter of the city in effect at the time this charter is adopted. At each biennial general election after this charter takes effect, four councilmembers, one from each ward, shall be elected, each for a term of four years, so that the councilmembers in each ward are biennially elected for overlapping terms. To qualify for election and to hold office, a councilmember must be and remain a resident of the ward the member represents.