Ok, let me put it another way. Green and red are clearly different colors, right? But if you make a gradient where the green smoothly transitions to the red, there isn’t one single point where it changes from “green” to “red”. This doesn’t mean that the two colors on the ends aren’t completely different colors, it means that when you look at every pixel, they’re almost exactly the same color as the pixel next to them.

Different species exist. Speciation is a thing. I’m not claiming otherwise. But creatures don’t birth a species other than their own. It takes many many many generations over eons of time for a population to speciate. Speciation is something that happens to populations, not individuals.