It's very simple. Creatures evolve to adapt to their environment as the environment changes. Those that are unable to adapt become extinct. That is the natural way of life.
Did I go too fast for you?
Tsk, why did you do that...now be ready for junk thrown your way...
Actually, the one line in your post that dealt with evolution, "Creatures evolve to adapt to their environment as the environment changes." was not the theory of evolution. It was an application of PART of certain theories of evolution. Except that it is not 'creatures' it is 'species' or in some cases whole 'genuses'.
There are many theories:
1) Darwinism
2) Incrementalism
3) Quantum leap
4) Random mutation
5) Guiaism (a number of variations basically incremental and/or Quantum leap directed or at least influenced by some supernatural diety)
6) Other
These theories and variations of them are used most often to explain the development of species from simpler to more complex forms. Some argue they are missapplied and that species simply "evolve" through various 'conditions' that are within their genetic makeup.
Origin of life is another whole set of theories. Creationism should fall into this set if it is given any credence at all by an individual.
*** You mentioned species decoming extinct if they are unable to adapt. This has nothing to do with (the) theory of evolution as species could become extinct irrelevant of whether their genus was stagnant or not. But thanks for the random factoid.
*** You also asked if you went to fast for me. No, I think you went to fast for your own self.
My comment: Your original post was obnoxious. Your response was both lacking and confused. I think this is where according to your original post you should consider sitting down, shutting up and getting out of the way.