I'll start with evolutionism, and that by defining my use of the term. When I refer to "evolutionism," I am not referring strictly to the principles of biological evolution — natural selection and what have you — some of which I have no fundamental issue with when speaking of adaptation at the sub-orderial level (i.e. microevolution). Rather, I am referring to the philosophical underpinning that is used to interpret our observations of the material world, and which posits that "change" in the physical world is completely naturalistic, that there is no supernatural, there is no outside Being who created or interferes in the operation of things in this universe. As such, the term "evolutionism" encompasses everything from cosmology to biology (via the unsubstantiated suppositions of macroevolution) and the philosophical hand-waving that is used to support non-theistic arguments in these areas.
Evolutionism starts from essentially the same pagan first principle as did the ancient mythologies — that of the eternal pre-existence of the cosmos as a self-contained (even if not yet in finished form) whole. To the ancients, it was an eternally pre-existent heaven and earth whose pre-existence was never rationally explained, and rarely addressed. Today, it manifests itself as a variety of competing cosmological theories, the most prominent of which are the steady-state theory of Fred Hoyle (which has fallen out of favor) and the more well-known Big Bang theory. Both theories implicitly rest on the premise of eternal pre-existence without an initiatory Creator. The steady state theory suggested that the universe has no beginning and will have no end, and will always appear to us to be the same (on an extremely large cosmological scale, of course, change and greater order are accounted for at lower levels like, say, the galactic). The Big Bang, which has largely supplanted the steady state theory, while appearing to suggest that the universe has a beginning (the singular point from which everything "banged"), nevertheless fails to explain where that point came from — meaning once again the rejection of a Creator and the positing of an eternally pre-existing cosmos in some form or another.