Invertebrates – Animals without backbones

Invertebrates are animals without a backbone. Of the planet’s estimated 15-30 million animal species, 90% or more are invertebrates.

Marine and freshwater invertebrates include the following groups, some of which have land-dwelling members also:

  • Mollusca
  • Echinodermata
  • Annelida
  • Crustacea
  • Porifera
  • Cnidaria
  • Bryozoa

(Australian Museum, 2009)