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Mollusks. Emily Yau and Bridget Waas. Germ Layers. Mollusks are tripoblastic : they have three germ layers Endoderm, ectoderm, and mesoderm. Symmetry. Most of mollusks are bilaterally symmetrical. Coelom. Mollusks are coelomates, and have a true coelom
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Mollusks Emily Yau and Bridget Waas
Germ Layers • Mollusks are tripoblastic: they have three germ layers • Endoderm, ectoderm, and mesoderm
Symmetry Most of mollusks are bilaterally symmetrical
Coelom 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)
Digestive Tract • All mollusks have a complete digestive tract • Mouth, stomach, and anus • Tube-like
Cephalization Evidence of cephalization increases from chitons to cephalopods
Segmentation None!
Skeleton and Appendages Most mollusks have a hydrostatic skeleton or an exoskeleton The number of appendages change from species to species
Circulatory System • A mollusk’s circulatory system is mainly open • No true heart or capillaries
Respiratory System Most mollusks have one gill or one pair of gills Some land mollusks have lungs
Reproduction Assexual or sexual, depending on the species
Habitat Mollusks are found everywhere, but most live in marine environments