BIOL 202 Lecture Notes - Lecture 7: Pulmonata, Symmetry In Biology, Ceratia
21 Jan 2016
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Molluscs (phyla: protostomes, lophotrochozoa, eumetazoa, 8 classes, ~100,000 species (large amount of diversity, older than annelids, coelomate - complex organ systems, bilateral symmetry, triploblastic, foot. No organs: visceral mass with calcareous shell. Mantle secretes shell: aquatic molluscs have true gills, terrestrial (most gastropoda) have pulmonate lungs, larvae undergo torsion (180 ) Mantle cavity and anus twist from back to front. Better chance of having freshwater over gills. Can curl head into mantle cavity for protection. Caused some originally paired organs to be singular (loss of bilateral symmetry: many have a coiled shell, marine, freshwater, terrestrial, intermediate hosts for trematodes, ceratia extension of coelom. Can retract eyespot more quickly than they can expand them. Hydraulic comes from manipulation (pushing) of water around in body: scrape algae or flesh using radula, gas exchange involves the mantle cavity, mostly dioecious, sequentially of hermaphrodite. When bottom dies, pheromonal transition of next one up to.
