  We report experimental and theoretical results on spatiotemporal pattern
formation in cell populations, where the parameters vary in space and time due
to mechanisms intrinsic to the system, namely Dictyostelium discoideum (D.d.)
in the starvation phase. We find that different patterns are formed when the
populations are initialized at different developmental stages, or, when
populations at different initial developmental stages are mixed. The
experimentally observed patterns can be understood with a modified
Kessler-Levine model that takes into account the initial spatial heterogeneity
of the cell populations and a developmental path introduced by us, i.e., the
time dependence of the various biochemical parameters. The dynamics of the
parameter agree with known biochemical studies. Most importantly the modified
model reproduces not only our results, but also the observations of an
independent experiment published earlier. This shows that pattern formation can
be used to understand and quantify the temporal evolution of the system
parameters.
