This document discusses the classification of living things into five kingdoms, with a focus on the animal kingdom. It describes that the animal kingdom is divided into invertebrates without backbones and vertebrates with backbones. Invertebrates include sponges, cnidarians, molluscs, annelids, arthropods, and echinoderms. Vertebrates have an internal skeleton, digestive system, and other characteristics. Examples of invertebrate phyla described in more detail include sponges, cnidarians, flatworms, nematodes, annelids, molluscs, arthropods, and echinoderms.