All I can do is add more confusion for you. There is a group of biologists who want to throw out all the Latin nomenclature of Genus species, etc., and group all organisms into something called Clades. Every 'species' would have its own number. Some biologists are of course unhappy with the whole idea of replacing names with numbers. So the taxonomy communities are in an even greater state of flux now with the incredible amounts of new info flowing in from DNA sequences, which often throws off the old ideas of who was related to whom.

I was shocked to discover in Weeds of the West that many of the plant family names I had learned in the 60's have been changed to new names. We will keep getting new info about genetic relationships for a long time still. So I think you can just learn what the textbook says and remember that we're still far from sure how classifications will end up.