  Accurate synthetic models of stellar populations are constructed and used in
evolutionary models of stellar populations in forming galaxies. Following their
formation, the late type galaxies are assumed to follow the Schmidt law for
star formation, while early type galaxies are normalized to the present-day
fundamental plane relations assumed to mimic the metallicity variations along
their luminosity sequence. We then compute predictions of these models for the
observational data at early epochs for various cosmological parameters $\Omega,
\Omega_\Lambda$ and $H_0$. We find good match to the metallicity data from the
damped $L_\alpha$ systems and the evolution of the luminosity density out to
$z\simeq 1$. Likewise, our models provide good fits for low values of $\Omega$
to the deep number counts of galaxies in all bands where data is available;
this is done without assuming existence of extra populations of galaxies at
high $z$. Our models also match the data on the redshift distribution of galaxy
counts in $B$ and $K$ bands. We compute the predicted mean levels and angular
distribution of the cosmic infrared background produced from the early
evolution of galaxies. The predicted fluxes and fluctuations are still below
the current observational limits, but not by a large factor. Finally, we find
that the recent detection of the diffuse extragalactic light in the visible
bands requires for our models high redshift of galaxy formation, $z_f
\geq$(3-4); otherwise the produced flux of the extragalactic light at optical
bands exceeds the current observational limits.
