Invertebrate GroupsSimplest animals

Contains the greatest number of animal species

Most found in water Do not have a backbone

Includes sponges, cnidarians, flatworms, roundworms,

annelids (segmented worms), mollusks, arthropods, &

echinoderms

CLASSIFICATION SCHEME

KINGDOMPHYLUM

CLASSORDER

FAMILYGENUS

SPECIES

PHYLUMPORIFERA

MEANS “PORE

BEARING”

PHYLUM

MEANS “STINGING

CELLS”

CNIDARIA

PHYLUMNEMATODA

“ROUNDWORM”

MEANSPINWORMS

HOOKWORMS

TRICHINELLA

PHYLUMPLATYHELMINTHESMEANS

“FLATWORMS”PLANARIAN

PHYLUMMOLLUSCA

MEANS-SOFT-BODIED

CLASSGASTROPODA

MEANS:STOMACH-FOOTED

CLASSBIVALVIA MEANS:

TWO-SHELLED

SCALLOP

CLASSCEPHALOPODA

MEANS:

HEAD-FOOTED

PHYLUMANNELIDA

MEANS: SEGMENTED

PHYLUM

ARTHROPODA

MEANS:JOINTED APPENDAGES

PHYLUMECHINODERMA

MEANS SPINY-SKINNED

• -poda - footed• Bi- two• Echino- spiny• Poly- many• -derma - skin• Cephalo- head• Gastro- stomach• -valvia - shell• Pori- pores