An invertebrate is any multicellular animal lacking a backbone. This includes all animal phyla other than Chordata. The major invertebrate phyla include:
- Sponges - Porifera
- Coelenterates - Cnidaria
- Ctenophores - Ctenophora
- Echinoderms - Echinodermata
- Flatworms - Platyhelminthes
- Roundworms - Nematoda
- Segmented worms - Annelida
- Mollusks - Mollusca
- Arthropods - Arthropoda
Invertebrates are tremendously diverse, ranging from microscopic wormlike mezozoans to huge animals such as the giant squid. Approximately 95% of all the earth's animal species are invertebrates; of these, the vast majority are insects and other arthropods. Invertebrates are important as parasites and are essential elements of all ecological communities.
More: Overview of Invertebrates ...
