  We quantify the evolution of matter and galaxy clustering in cosmological
hydrodynamical simulations via correlation and bias functions of matter and
galaxies. We use simulations TNG100 and TNG300 with epochs from $z=5$ to $z=0$.
We calculate spatial correlation functions of galaxies, $\xi(r)$, for simulated
galaxies and dark matter (DM) particles to characterise the evolving cosmic
web. We find that bias parameters decrease during the evolution, confirming
earlier results. At low and medium luminosities, bias parameters of galaxies,
$b_0$, are equal, suggesting that dwarf galaxies reside in the same filamentary
web as brighter galaxies. Bias parameters of the lowest luminosity galaxies
estimated from CFs are lower relative to CFs of particle density-limited
clustered samples of DM. We find that bias parameters $b_0$, estimated from CFs
of clustered DM, agree with the expected values from the fraction of particles
in the clustered population, $b=1/F_c$. The cosmic web contains filamentary
structures of various densities, and fractions of matter in the clustered and
the unclustered populations are both less than unity. Thus the CF amplitude of
the clustered matter is always higher than for all matter, i.e. bias parameter
must be $b>1$. Differences between CFs of galaxies and clustered DM suggest
that these functions describe different properties of the cosmic web.
