At root is the concept of speciation, in which an entirely new species is made from existing ones. By species though, all that truly has to apply is that the animals do not mate with one another. It does not, in nature, necessarily have to take on the scientific ideal that their gametes will literally NOT cause blastula formation.
Examples of this are literally everywhere, of speciation:
1) Mule dear and whitetail deer, blacktail deer, elk....all of these are thought to be VERY recent breakoffs of a common ancestor, and their continued speciation is seen everywhere that the species co-exist. In part of the American West, for example, whitetail deer are under tremendous predation pressure. Because of this, as I can attest to personally, whitetails out there are typically larger than they are found elsewhere. They also have larger ears, as many of the large predators found there give strong selection pressure to it. Contrasting this to the whitetails where I live, there is a strong selection pressure here to be mobile, faster, as starvation and smaller animal predation is the pressure.....make no mistake; this is MACRO-evolution at work. These are now two totally different species, with different mating patterns, size, physiology, WITH mixed-breeding of the larger whitetails....this actually gives even more genetic advantage, as a whitetail that is large enough, big-eared enough, are found to mate with MULE deer. This produces a genetically superior offspring, as the fawn is larger than its competition. It has occurred over many generations even recently, with marked speciation.
One can apply this same process to squirrel (gray vs red, now different species that do not mate with one another), salmon (sockeye vs keta), foxes, etc....all of these are showing active speciation.
2) The debate about where micro becomes macro is as old as evolution itself. The overwhelming consensus is that this line is completely artificial, and has never been accurately defined....what if one set of bears decides to move to higher elevations in a given place for food reasons, just by chance....and only the offspring that are large enough to now be able to take on the prey at that elevation, with the normal high culling rate in nature....and if over many generations the higher elevation, now more predator-like bears will no longer mate with the smaller ones down below.....is this a new species? Most would say yes, as I have just described black vs brown bears. In many places though, they intermingle, and DO interbreed. This is the key, the intermediate step.
3) Describing evolution in Darwinian terms is indeed a false argument, as the science has progressed so far since then....the REAL question for skeptics of macro-evolution is much simpler: find peer-reviewed studies by multiple scientists that have successfully challenged and won the debate in proving it does not exist....so far, this has not happened.
4) The idea that "ergo, God exists" is an absurdity, especially in an argument set upon the idea of "irreducible complexity". In order for their to be a complex God, there must have been an even MORE complex God that it came from. If this is not the case, then the idea that there must be a "beginning to everything" has collapsed.
5) Overall, I am not arrogant enough to believe that I alone have discovered truths that much smarter men and women have not thought of, put forth, and had defeated. I believe that evolution exists not out of conformity, but out of respect for the fact that all of these questions have been asked for 150 years without success. I do not claim to understand all about evolution, as no one probably should, but I am a believer in consensus. It has been said that there are far more scientists that have successfully challenged key parts of the the theory of relativity, or newtonian gravity, than have successfully challenged evolution. In other words, if we are questioning even these ideas with such audacity, one may as well attempt to discredit thermodynamics or mendelian genetics. Evolution is a much harder target than either.
"The soul that does not attempt flight; does not notice its chains."