Invertebrates are animals that lack a backbone or vertebral column. They make up over 95% of the animal kingdom and include animals such as insects, spiders, snails, and jellyfish. Vertebrates, on the other hand, are animals that have a backbone or vertebral column. This group includes animals such as fish, birds, reptiles, and mammals. One key difference between the two groups is the presence or absence of a backbone, which provides structural support and protects the spinal cord.