This document discusses and compares vertebrates and invertebrates. Vertebrates are animals with backbones, and there are five classes: fish, amphibians, reptiles, birds, and mammals. Each class is then described in 1-2 sentences. Invertebrates are animals without backbones that can take care of themselves after hatching from eggs. Insects are described as the largest group of invertebrates, having six legs and one or two pairs of wings.