By using a one-zone chemical and spectrophotometric evolution model of a di
sk galaxy undergoing a dusty starburst, we investigate numerically the opti
cal spectroscopic properties in order to explore galaxy evolution in distan
t clusters. We adopt an assumption that the degree of dust extinction (repr
esented by Av) depends on the ages of starburst populations in such a way t
hat younger stars have larger Av (originally referred to as selective dust
extinction by Poggianti & Wu). In particular, we investigate how the time e
volution of the equivalent widths of [O II] lambda 3727 and H delta are con
trolled by the adopted age dependence. This leads to the following three ma
in results: (1) If a young stellar population (with an age of similar to 10
(6) yr) is more heavily obscured by dust than an old one (> 10(8) yr), the
galaxy can show an " e(a) " spectrum characterized by strong H delta absorp
tion and relatively modest [O II] emission. (2) A dusty starburst galaxy wi
th an e(a) spectrum can evolve into a poststarburst galaxy with an a + k (o
r k + a) spectrum 0.2 Gyr after the starburst and then into a passive one w
ith a k-type spectrum 1 Gyr after the starburst. This result clearly demons
trates an evolutionary link between galaxies with different spectral classe
s [i.e., e(b), e(a), a + k, k + a, and k]. (3) A dusty starburst galaxy can
show an a + k or k + a spectrum even in the dusty starburst phase if the a
ge-dependence of dust extinction is rather weak; i.e., if young starburst p
opulations with different ages (less than or equal to 10(7) yr) are uniform
ly obscured by dust.