Properties of Galaxies and Groups: Nature versus Nurture
  Due to the inherently nonlinear nature of gravity cosmological N-body
simulations have become an invaluable tool when the growth of structure is
being studied and modelled closer to the present epoch. Large simulations with
high dynamical range have made it possible to model the formation and growth of
cosmic structure with unprecedented accuracy. Moreover, galaxies, the basic
building blocks of the Universe, can also be modelled in cosmological context.
However, despite all the simulations and successes in recent decades, there are
still many unanswered questions in the field of galaxy formation and evolution.
One of the longest standing issue being the significance of the formation place
and thus initial conditions to a galaxy's evolution in respect to environment,
often formulated simply as "nature versus nurture" like in human development
and psychology. Unfortunately, our understanding of galaxy evolution in
different environments is still limited, albeit, for example, the
morphology-density relation has shown that the density of the galaxy's local
environment can affect its properties. Consequently, the environment should
play a role in galaxy evolution, however despite the efforts, the exact role of
the galaxy's local environment to its evolution remains open. This thesis
introduction discusses briefly the background cosmology, cosmological N-body
simulations and semi-analytical models. The second part is reserved for groups
of galaxies, whether they are gravitationally bound, and what this may imply
for galaxy evolution. The third part of the thesis concentrates on describing
results of a case study of isolated field elliptical galaxies. The final
chapter discusses another case study of luminous infra-red galaxies.
