Intro to Zoology/Invertebrate Zoology

Invertebrate zoology is the study of animals that lack a spinal column (backbone). It includes the study of their behavior, ecology, anatomy, and evolution. This is in contrast to vertebrate animals.

The latest estimates suggest invertebrates make up about 97% of the Earth's animals. They range in size from minute to extremely large. Some, like insects, have an exoskeleton, which is a support structure like our own skeleton, but is on the outside of the animal. Others have hard internal support structures, some have no hard parts at all.

Invertebrate animals include protozoans, annelids, cnidarians, echinoderms, flatworms, nematodes, mollusks, and arthropods.