Does that mean you’re not interested in defining differences between bacteria anymore?
A proper analysis will determine if a nested hierarchy is just a human construct that sort of resembles the data, or if a nested hierarchy is actually the best fit explanation for the data. But honestly I don’t know why you would need a detailed study to prove this; all you have to do is look at any number of categories of animals, like vertebrate, tetrapod, mammal, rodent, house mouse, and you see nested hierarchies. Genesis doesn’t describe why ‘mammal’ is a real category, but that doesn’t mean it’s not describing the real world.
So basically, either God created animals in nested hierarchy categories that looked like a pattern of descent, or animals all actually descended from common ancestors. This is only confirmed, and strongly, when you look at the genetic data. If you’re interested in actually looking at such a study, there was discussion of one here not long ago: