Very true. We as a species are very quick to differentiate ourselves and set ourselves above all other animals. That is not justification for mistreatment. I will not try to deny that there are differences, and we have evolved well beyond many other animals is some areas, especially our own hubris.
I also have always lumped humans in with animals. We are just differently evolved. If anything that gives us more responsibility to other animals. Granted, Bob, though it doesn’t surprise me... you’re the first person I’ve ever heard give Protozoa their own category.
Linnaeus originally recognized only two kingdoms - animals and plants.
But we have learned a lot more about life forms since then and have added to the different types.
From Wikepedia:
Traditionally, some textbooks from the United States and Canada used a system of six kingdoms (Animalia, Plantae, Fungi, Protista, Archaea/Archaebacteria, and Bacteria/Eubacteria) while textbooks in countries like Great Britain, India, Greece, Brazil and other countries use five kingdoms only (Animalia, Plantae, Fungi, Protista and Monera).