Here's an amusing thought experiment:
Assume for the sake of the hypothetical that evolution is dead wrong, that species do not develop from one another.
That necessarily requires that each species have been born as-is, with all the complexity that it has.
The fossil record, sparse as it is, clearly demonstrates that many species that are alive today - I will reserve comment on Homo Sapiens for obvious reasons - were not in existence from the very beginning. There were no horses during the age of the trilobite.
That means that many of our current species - in fact, I would hazard to guess all current species - must have suddenly "shown up" on some particular day in some particular year. And would have had to show up fully developed and, in order for the first members of this new species to breed, would have had to be fully grown.
In other words, about 5 million years ago, on some warm sunny day, there was a >POP<, a rush of air, and lo and behold, a breeding pair of horses, of the genus Equus, materialized out of thin air.
If species do not evolve one from the other, and if not all present-day species were present at the dawn of creation, then that is, more or less, about the only other way our current species got here.
In short: if Species B was not born of Species A, and if Species B was not present at creation, then - since Species B is demonstrably present now - the only way for Species B to have arrived here would be for it to spring fully developed out of thin air. There is no other alternative that bears any relationship to the natural world as we know it.
