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S2: “Know your mussel”. Kingdom Animalia Animalia Phylum Mollusca Chordata Class Bivalvia Mammalia Order Mytiloidea Primates Family Mytilidae Hominidae Genus Mytilus Homo Species trossulus sapiens. Mollusks. Usually have: Shell secreted by mantle
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S2: “Know your mussel” Kingdom Animalia Animalia Phylum Mollusca Chordata Class Bivalvia Mammalia Order Mytiloidea Primates Family Mytilidae Hominidae GenusMytilus Homo Speciestrossulussapiens
Mollusks • Usually have: • Shell secreted by mantle • A head, foot, and gills • A specialized feeding structure (radula) • A "trochophore" larval stage • Exceptions exist but the basic plan is unmistakable BIODIDAC, University of Ottawa
www.whoi.edu/science/ B/aplacophora/ Photo by R. Willen Mollusca Gastropoda Cephalopoda Bivalvia • Incredible diversity of form and lifestyle • Second largest phylum (after Arthropoda) with 50,000 extant species and 35,000 fossil species http://www.pmel.noaa.gov/vents/nemo/explorer/bio_gallery/biogallery1.html Monoplacophora Polyplacophora Scaphopoda Aplacophora http://www.fish.washington.edu/naturemapping/mollusks/mono/6mono_int.html http://ourworld.compuserve.com/homepages/BMLSS/molluscs.htm http://www.biology.ucok.edu/AnimalBiology/Mollusca/Scaphopoda.html
Bivalves Photo by Keith Hiscock • Two shells joined by hinge • Laterally (left to right) compressed • Reduced head lacking eyes & tentacles • Primitively, a narrow foot adapted for burrowing http://www.marlin.ac.uk/learningzone/species/LZ_Ostedu.htm Photos by Bill Austin, Marine Ecology Centre http://www.mareco.org/rocky/mussel_relatives.html
Mussels • "Mussel" is a common name for bivalves that attach using threads (byssus) • Freshwater and marine mussels are not closely related (example of convergent evolution) The marine mussel, M. galloprovincialis The infamous invasive freshwater zebra mussel, Dreisenna polymorpha
Mussels • Adapted to hard surfaces • Byssal threads • Can move by detaching and reattaching threads • Small and fingerlike foot for • Positioning new threads • Crawling in small mussels • Adapted for group living • Anterior ends tapered • Posterior ends (with siphons) elevated Photo credit: MLML staff