If they can breed, they are the same species. if they have diverged enough that they cannot breed, then they are different species.Why that's like a poodle breeding with retriever and claiming evolution.
The problem with this definition is that species *do* change over geologic time. So you either have to include very different creatures under the same 'kind', or you have to realize that another definition of species is required to describe reality.Play with your word species. Long before science invented the word and it's meaning, there was the definition of kinds of animals in which one kind has never changed to another kind. That would be macro evolution.
In particular, species can *split* into sub-populations that do not interbreed and can, after long time spans, look quite different. Under your definition, the two populations would be the same 'kind', but they would be considered by everyone else to be different species.
Each generation is only a 'micro-evolution' away from the previous generation. It is only a 'micro-evolution' away from ancestors a mere 10 generations back. But the difference increases over time and eventually the differences are major. This tends to take hundreds to tens of thousands of generations.
Again, a coin analogy. We start adding pennies to a pile of coins. it starts being a 'small amount' of money. no single penny changes it from a 'small amount' to a 'large amount'. Yet, after enough pennies have been added, there is a 'large amount' of money. Each addition of a penny, or even of ten pennies, is a 'micro-change'. But, those changes add up to be a 'macro-change'.
So, you have claimed that 'kinds' cannot cross some sort of barrier. Biologists have not found any such barrier. What, exactly, is the mechanism for that barrier? What evidence do you have for such a barrier? How do you know it cannot be crossed?