Mollusks Emily Yau and Bridget Waas

 Mollusks are tripoblastic: they have three germ layers  Endoderm, ectoderm, and mesoderm Germ Layers

 Most of mollusks are bilaterally symmetrical Symmetry

 Mollusks are coelomates, and have a true coelom  Most coeloms are small and located around the heart, gonads, and metanephridia (organ similar to the kidneys) Coelom

 All mollusks have a complete digestive tract  Mouth, stomach, and anus  Tube-like Digestive Tract

 Evidence of cephalization increases from chitons to cephalopods Cephalization

 None! Segmentation

 Most mollusks have a hydrostatic skeleton or an exoskeleton  The number of appendages change from species to species Skeleton and Appendages

 A mollusk’s circulatory system is mainly open  No true heart or capillaries Circulatory System

 Most mollusks have one gill or one pair of gills  Some land mollusks have lungs Respiratory System

 Assexual or sexual, depending on the species Reproduction

 Mollusks are found everywhere, but most live in marine environments Habitat