  Recent morphological studies of galaxies by the {\it Hubble Space Telescope
(HST)} have revealed that actively star-forming galaxies at intermediate and
high redshifts ($z=0.5-2.0$) have very clumpy and irregular distributions of
stars. It is however unclear whether and how these clumpy galaxies evolve into
the present spiral and elliptical galaxies with regular shapes. We here propose
that spatial distributions of AGB stars, probing the different mean age and
metallicity of the underlying stellar population, can provide vital clues to
the evolution of these clumpy galaxies, in particular, those at intermediate
redshifts. In order to demonstrate this proposal to be quite promising, we show
the results of test-particle simulations on the long-term dynamical evolution
of unbound groups of AGB stars (``stellar clumps''), which correspond to the
successors of star-forming clumps at intermediate redshifts, in isolated and
interacting galaxies. We particularly show that azimuthal distributions of AGB
stars dispersed from stellar clumps as a result of gravitational interaction
with their host galaxies can be still inhomogeneous several Gyrs after stellar
clump formation for some models. We also show that the inhomogeneities in the
azimuthal distributions of dispersed AGB stars can more quickly disappear in
stellar clumps with larger sizes and higher velocity dispersions. These results
suggest that if apparently clumpy structures of galaxies at intermediate
redshifts are due to stars in unbound or weakly bound clusters, spatial
distributions of AGB stars can have fossil records on past clumpy structures of
galaxies.
