Invertebrates, also known as inverts, are a diverse group of animals that simply lack a back bone.  They are found in all parts of the world and are well known for their scavenging skills as well as their filter feeding and "cleaning" abilities. While a Starfish or Sea Urchin may be easily recognized, Invertebrates include some very odd members, such as a Sea Apple or Nudibranch. Invertebrates are a necessary component as they remove debris, and absorb and filter minerals to keep a balanced environment.