Patterns of transition between several terms in the spherical mean-field plus quadrupole-quadrupole and pairing model within two-j shells are studied. By analyzing the variational features of the quantities in the quadrupole-quadrupole term to pairing term, mean-field term to quadrupole-quadrupole term, and mean-field term to pairing term, we find that with the even-n cases, some observables such as low-lying energy level ratio E(41+)/E(21+), the overlap |〈41+;x0|41+;x〉| with x0=0 and x0=1, B(E2;41+→21+) and electric quadrupole moment value Q(41+), are sensitive with respect to a control parameter or the number of valence nucleons. The investigation also indicates that increasing the spacing of single-particle energy level can produce the significant transitional behavior.