Effects of selection on K-carrier frequency up to a threshold (T) has been attained. All patterns of age structure are provided. SchemeA2 (selection on the overall population) and SchemeB2 (selection on closed-nucleus). Selection ceases after K-carrier frequency has attained the thresholds T > 0.4, > 0.6, and 0.8. Under SchemeB2, selection on the nucleus ceases after the above-mentioned frequencies have been attained. The next year the reproductive separation between nucleus and base is completely lifted, after which N + B is the frequency of the K-carriers in the overall population.