Again I agree with you completely. However, about the species thing --
"Species" is usually defined as an interbreeding, distinct population, often separated geographically from similar populations.
Dogs are one species because, regardless of size, color, and other traits, they are more than willing to breed with one another. That is because their breeding cues are olfactory -- scent-based. Horses, for example, are the same.
HOWEVER, take a look at hummingbirds. There are hundreds of defined species, all of which refuse to interbreed with each other and some of which it takes an expert to tell apart! Why? Because hummingbirds depend on sight cues for breeding. The tiniest difference in appearance makes a world of difference. So we have LOTS of hummingbird species and ONE domestic dog species.
Hopefully that demonstrates how silly the designation of 'species' is. So best to use the word 'kind' or 'type' when saying that one of them cannot change into another of them. We do see speciation, but we have never seen a change from basic type.
Make sense?