BIO 200 Lecture Notes - Lecture 19: Nematomorpha, Mollusca, Flat Feet
26 Oct 2018
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Who are the animals again: lophotrochozoans revisited, mollusks are diverse, mollusk body plan, mollusk reprod, 4 classes of mollusks, what is an ecdysozoan, horsehair worms + nematodes, velvet worms + water bears, arthropods. Dev of 3 part body plan in mollusks. Mollusk characteristics: visceral mass: holds + clusters organs in center of body, foot: muscular + tough on base. Locomotion, attachment, food capture (excrete mucus as they move: mantle: thickened skin sheet. Secretes protective shell (obv not all have shells) Cephalization: variable (range from pronounced to bivalves w no head) Radula: specialized mouth part: large group of micro teeth in rows used to scrape algae off substrate, againnot all have (bivalves w none vs gastropods w drills to get into prey) Cross-fertilization common: some sex switchers, aquatic: ext fertilization to release gametes into h20, terr gastropods: internal mechanisms to avoid dessication. Bodies w 8 overlapping dorsal plates; creep along broad flat foot. Herbivorous: scrape algae off rocks w radula.
