Dalhousie University Biology 2003: Animal Diversity Lecture 10 PDF

Dalhousie University operates in the unceded territories of the Mi’kmaw, Wolastoqey, and Peskotomuhkati Peoples. Dalhousie University also acknowledges the histories, contributions, and legacies of African Nova Scotians, who have been here for over 400 years. Biolo...

Dalhousie University operates in the unceded territories of the Mi’kmaw, Wolastoqey, and Peskotomuhkati Peoples. Dalhousie University also acknowledges the histories, contributions, and legacies of African Nova Scotians, who have been here for over 400 years. Biology 2003: Animal Diversity Lecture 10: Phylum Mollusca (Part 1) By C. Isabelle Aubé (she/her) All slides herein forward adapted from J. Frail-Gauthier, J. Bennett, and McGraw Hill LLC Lecture 10 textbook readings: Ch. 10.1-10.3, 10.11 All images herein forward from Hickman et al. (2021) or attributed within. https://www.worldatlas.com/animals/sea-snail.html L09 Review:  Today’s Lecture I. Phylum Mollusca (Part 1) Introduction Molluscs and Us (Human Importance) What Makes a Mollusc a Mollusc ̶ Head-Foot ̶ Visceral Mass ̶ Basic Internal Characteristics ̶ Reproductive System II. Phylum Mollusca (Part 2) Phylogeny & Characteristics of the 8 Classes: ̶ Caudofoveata, Solenogastres, Polyplacophora, Monoplacophora, Gastropoda, Bivalvia, Scaphopoda, Cephalopoda Phylum Mollusca Bilateria Nephrozoa © McGraw Hill LLC The next great Lophotrochozoans-->Trochozoans: the Molluscs! https://petesaquariums.com/shop/invertebrate-fish/octopus/blue-ringed-octopus/ Larval form: trochophore By authors: Carmel McDougall, Wei-Chung Chen, Sebastian M Shimeld and David EK Ferrier - cropped from Figure 1 http://www.frontiersinzoology.com/content/3/1/16/figure/F1Carmel McDougall, Wei-Chung Chen, Sebastian M Shimeld and David EK Ferrier (2006) The development of the larval nervous system, musculature and ciliary bands of Pomatoceros lamarckii (Annelida): heterochrony in polychaetes. - Frontiers in Zoology 2006 3:16 doi:10.1186/1742-9994-3-16. (Cropped by User:Snek01), CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=5054052 © McGraw Hill LLC  Phylum Mollusca From Latin molluscus = “soft” Extremely diverse (~90K living spp.) & disparate (8 Classes) – Simple to some of the most complex invertebrates! – E.g., snails, clams, chitons, octopuses, nudibranchs https://www.quora.com/What-is-a-bivalve-mollusk Cosmopolitan distribution: marine, FW, terrestrial Carnivores, herbivores, filter feeders, parasites… Most are small (18 m)! Human importance! Molluscs and Us 1. Food – Calamari, escargot, mussels, scallops, clams… – Threatened by climate change→CO2→ocean acidification→weak shells https://brianskerry.com/portfolio/aquaculture/attachment/mm7907_110628__014027-3/ https://www.myrecipes.com/recipe/fried-calamari-with-roasted-garlic-lime-aoli IMAGE: JAMESON FINK / FLICKR Molluscs and Us 2. Pearls & Shells – Cowries = currency! https://www.reef2reef.com/threads/slug-type-creature.738927/ https://naplesseashellcompany.com/money_cowrie_sea_shells.html https://medium.com/psihoyos-photography/tahitian-black-pearls-411efc243405  https://marinesciences.uconn.edu/2019/10/30/plastic-pollution-needs-a-new-bioindicator/ Molluscs and Us 3. Bioindicators – Environmental indicators … and filters! Photograph by MARYLAND SEAFOOD http://kth.diva-portal.org/smash/get/diva2:413126/FULLTEXT02.pdf Molluscs and Us Public Domain, https://commons.wikimedia.org/w/index.php?curid=2143950 4. Pests – Bites, stings, crops, parasites/intermediate hosts, biofouling https://www.researchgate.net/publication/23135779_The_NIH-NIAID_schistosomiasis_resource_center Image by tepic  Credit: Matter Molluscs and Us 5. Biotechnological /medical importance –Shell strength, nerve cells & axons, venom The Archimollusc: Hypothetical Ancestral Mollusc (HAM) What Makes a Mollusc a Mollusc? 1. Head-Foot 2. Visceral Mass 1. Head-Foot The Head – Feeding – Sense organs Brain, eyespots-to-eyes, tentacles https://www.pinterest.ca/pin/4292562130256132/ https://wallspic.com/tag/invertebrates  1. Head-Foot The Radula – Chitinous ribbon of teeth – NOT in any Bivalve – Odontophore cartilage holds teeth Separate muscles to move odontophore (in/out) & radula  Snail Radula https://www.youtube.com/watch?v=LoxxMa8TrS8 1. Head-Foot The Foot – Locomotion, attachment – Ventral Photographer Chris Newbert https://es.educaplay.com/juegoimprimible/2841620-vertebrates_and_invertebrates.html PHOTOGRAPH BY DAVID DOUBILET  Close-up: Nerite Snail cleans glass https://www.youtube.com/watch?v=vzWzUw1OmEA A snail moving along and leaving its slime https://www.youtube.com/watch?v=pRmChG3Jf_Q  Cephalopods on the Move https://www.youtube.com/watch?v=PPYbjHwjNQc  Run, Octopus, Run! https://www.youtube.com/watch?v=23qzi88k3aM&t=11s 2. Visceral Mass Internal organs – Digestive, excretory, reproductive and respiratory https://molluscatravels.weebly.com/characteristics.html  2. Visceral Mass Mantle & Mantle Cavity MANTLE = the “skin” – Can have muscles, or chemoreceptors, etc – Makes the shell MANTLE CAVITY = open to “world” – Excretion (metabolic and digestive), respiration, reproduction, even jet propulsion!  2. Visceral Mass Image: Manfred Hyde, Wikimedia Commons Mantle & Shell Made by the outer layer of mantle Three layers: 1. Periostracum ̶ Outer organic layer (resistant protein https://www.frontiersin.org/articles/10.3389/fmars.2023.1154968/full conchiolin) 2. Prismatic layer ̶ Calcium carbonate stacks 3. Nacre ̶ Continuously thickens ̶ Calcium carbonate + Credit: Matter protein sheets ̶ AKA “mother of pearl” By Chris 73 / Wikimedia Commons, https://www.frontiersin.org/articles/10.3389/fmars.2023.1154968/full https://commons.wikimedia.org/w/index.php?curid=19711  Pearls https://cortezpearl.mx/pages/a-comprehensive-guide-to-pearl-varieties https://www.facebook.com/OMGFacts/photos/a.269222941494/10153825373491495/?type=3  Basic Internal Characteristics https://en.wikipedia.org/wiki/File:Open_circulatory_system.svg Bilaterally symmetric coelomates – (reduced coeloms) Mantle/cavity for respiration – Gills, lungs, diffusion Most have open circulatory system Complex digestive system Varied nervous system https://www.bbc.com/news/uk-england-devon-14018488  Reproductive System Almost never asexual Dioecious (separate males & females) or Trochophore monoecious (hermaphroditic) Trochophore larvae in most Veliger larvae common – Aquatic Bivalves and Gastropods Some have direct development (no larvae) Veliger Squid Eggs https://www.youtube.com/watch?v=xXd-sMm0G18 https://www.flickr.com/photos/christianloader/12739243295 Review 2. True or False. Phylum Mollusca is the most diverse Animal Phylum. Questions 3. What are 5 different ways that molluscs have human importance? Provide an example for each. 1. 4. A mollusc is composed of a ______________ (2 words) and a ____________________ (2 words). 5. What is the difference between the mantle, the Mollusca mantle cavity, and the shell https://commons.wikimedia.org/w/index.php?curid=18750276 of a mollusc? Organization Organ System 6. How are pearls made? 7. Two types of larvae found Symmetry Bilateral in molluscs are the _____________ and the Body cavity (Eu)coelomate _________________. Development Triploblasts 8. True or False. Some Protostome→Lophotrochozoa molluscs do not have a larval stage. Segmentation No 9. True or False. All molluscs are hermaphroditic.  Questions for me? Happy Dal Biodiversity Day! Mon Sept 30th: No Lecture (Truth & Reconciliation) Wed Oct 2nd:Mollusca (Part 2) Image: Solvin Zankl