Scientists classify the animal kingdom and sort them into 7 categories. The animal kingdom have different groups like invertebrates and vertebrates. They were put into place where they had lived.
Invertebrates are animals and insects with no backbones, (97% of the animal kingdom). Vertebrates are animals with backbones like birds, reptiles, amphibians, fish and mammals. Vertebrates have warm blood, hair and their mother.
Some of the groups are arthropods which include segmented body's and joined legs.
annelida also include worms.