BIOEE 1780 1st Edition Lecture 23Outline of previous lectureI. Announcement II. ReviewIII. AnimalsIV. SpongesV. EumetazoansOutline of current lectureI. LophotrochozoansII. FlatwormsA) TapewormsIII. AnnelidsA) EarthwormsB) LeechesIV. MollusksA) GastropodsB) CephalopodsC) BivalvesCurrent lectureI. Lophotrochozoans*Among the bilaterians, within protozoans *What do we know so far?-Flatworms: some are parasitic, hermaphrodites, bilateral, acoelomates, complex life cycles-Annelids: hermaphrodites, segmented, coelomates, fluid-filled coelom, closed circulatory system, complete digestive track-Mollusks: foot (large muscle to move around), some have an open circulatory system, coelomates, mantle-Synapomorphies: DNA, feeding tentacles, etcII. Flatworms*Flukes, tapeworms*Can be free-living or parasitic*Incomplete digestive tract*Bilateral triploblasts*No true body cavity, acoelomate: no specialized circulatory/respiratory organsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.*Most hermaphroditicA) Tapeworms*No digestive internal system (soak up nutrients through the skin)*Head with hooks and suckers (latch onto digestive tract)*Body composed of proglottids (but not true segments)*Tapeworm eggs were found in a 270 million year old shark poop (they are nearly identical to the ones we find today)*Some mom tricked her daughter into eating tapeworms so she would lose weight (do not try at home)*The longest tapeworm is over 30 feet!III. Annelids*Synapomorphies: segmentation, chitinous setae*The are coelomates A) Earthworms*Segmented with a closed circulatory system (means they can move very quickly)*Setae, most hermaphrodites*19000 species *Cephalization, no respiratory system, ventral nerve cord (runs along their belly)B) Leeches*Parasitic with specialized suckers*Segments modified*When feeding on a host they:-Anticoagulant-Vaso-dilators-Anesthetic*Hermaphroditic*Care for young (yes, leeches are great parents)IV. Mollusks*Synapomorphies: radula (for feeding), mantle*Diverse, species-rich*Mostly free-living*Closed/open circulation*Hermaphroditic and separate sexes*Decent with modification (foot, visceral mass, mantle)A) Gastropods*”Stomach foots”*Largest group of mollusks*Includes snails and slugs*Gastropod torsion: twisting of the mantle cavity (snails have an anus and gonads right above their heads)-Why is this advantageous? -Possibilities:#There is an extra space to pull in their head for protection#Can also enclose themselves in their shell to retain moisture-It was tested:#Pre-torted and newly-torted larvae were fed to various predators, let sit for 15 hours (the results are very weak, no conclusion has been drawn so far)*Adaptation to avoid fouling:-Incurrent and excurrent siphon and left gill-Variation in shell shape-Nudibranchs: evolutionary reversalB) Cephalopods*”Head foots” – agile predators, includes squids and octopuses, siphon, tentacles*Large brains… How smart are they?-One octopus sees another octopus in a different container opening a complex box to retrieve food-He was able to mimic the other one and get his food as wellC) Bivalves *Two shells: clams, oysters, mussels, scallops w/