Week 6 - Biol 112

Week 6 - Biol 112 - Invertebrate Diversity I Invertebrate...

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Unformatted text preview: Invertebrate Diversity I Invertebrate Diversity I Lab 7 Lab Safety – Biology 112 Lab Safety – Biology 112 Lab 7 – Invertebrate Diversity I Goggles and closed­toed shoes are required. Gloves need to be worn. Ascaris may be a low level biohazard. Although unlikely, eggs may survive chemical treatment and be viable. Wear gloves before handling Ascaris dissection specimens. Avoid skin contact. Avoid touching your face when dissecting Ascaris. Wash hands thoroughly with soap after dissections are completed. Do not eat or drink in lab. Follow general safety precautions and use common sense in addition to these guidelines. Ask your TA if there is doubt about any procedure. Finally, Kingdom Animalia! Finally, Kingdom Animalia! Some distinctive traits of animals: All are heterotrophs that use internal enzymes All are multicellular eukaryotes that use proteins to support their cells Muscle and nervous tissue unique to animals Specialized developmental process Animalia is a very diverse kingdom, so how can we classify its members? Traits used to classify animals (body plans): Traits used to classify animals (body plans): Symmetry Tissues and organ development Body cavities Embryonic development Let’s look at each of these closer: Types of symmetry… Types of symmetry… Asymmetrical (without (without symmetry) irregularly shaped (sponges) Types of symmetry… Types of symmetry… Radial Parts radiate from the center of an organism like a cycle wheel No left or right sides If cut longitudinally, two pieces are identical halves Can be cut at any point into mirror halves Types of symmetry… Types of symmetry… Bilateral Has a left and a right side If you cut down the center, two pieces are mirror images of each other Has anterior and posterior ends Germ (Tissue) Layers Germ (Tissue) Layers Endoderm­innermost layer Becomes: gut, liver, lungs Mesoderm­middle layer Becomes: skeleton, heart, kidney, muscle, blood Ectoderm­outermost layer Becomes: skin nervous system Germ (Tissue) Layers Germ (Tissue) Layers Diploblastic­two layers, endoderm and ectoderm only Triploblastic­ three layers, endoderm, mesoderm and ectoderm Body Cavity Body Cavity Acoelomate­ lack a coelom, no body cavity Pseudocoelomate­ body cavity not completely lined with mesoderm Coelomate­ body cavity fully lined with mesoderm Embryonic Development Embryonic Development Protostome­blastopore becomes the mouth Deuterostome­ blastopore becomes the anus More details on this next time Sponges Sponges Asymmetrical No tissues Sessile­ non­motile as adults Hermaphroditic­no separate sexes Their “skeleton” can be: Fibrous­soft, protein based Mineralized­hard, made of silicon dioxide or calcium carbonate Spicules Glass Sponge Sponge Anatomy Sponge Anatomy Cellular organization Choanocytes (collar cells)­ line pores and collect food using flagellum Amoebocytes­ able to move around the mesoglea with amoeboid movement to collect food, secrete calcium carbonate and silicon dioxide Spicules­ prickly like structure maintains shape Osculum­ water exits through this opening Spongocoel: cavity inside sponge Sponge anatomy Sponge anatomy Sponge Body Types: Sponge Body Types: Asconoid: choanocytes lining open spongocoel Synconoid: choanocytes line canals extending from spongocoel Leuconoid: Choancytes distributed along chambers that branch off from canals extending from spongocoel Most common Sponge Shapes Sponge Shapes Leuconoid Syconoid Asconoid Radial symmetry Radial symmetry Diploblastic (true tissues) Outer epidermis Inner gastrodermis Separated by gelatinous matrix= mesoglea Cnidocytes­specialized cells that contain nematocysts which sting prey for food or sting in defense Gastrovascular cavity­single opening for feeding Primitive nervous system Hydra Sea Anenome Jellyfish Cnidocytes and Nematocysts…. Cnidocytes and Nematocysts…. Two body forms Two body forms Polyp – sessile, attached to substrate Medusa­ mobile, free swimming Presence, absence, or alternation between body types varies for the four classes Class Hydrozoa Class Occurs in polyp and medusa form, diploblastic Polyp stage is often colonial (Obelia) E.g. hydras, Portuguese Man of War We have live Hydras, slides of Hydras, slides of Obelia, and preserved Man of Wars Class Schyphozoa Class Schyphozoa Medusa body form prominent, polyp form reduced Free swimming E.g. jellyfish Have statocysts: sense organs for orientation Class Cubozoa Class Cubozoa Four tentacles (or bunches of tentacles Box Shaped Well developed eyes Can be VERY Can deadly… deadly… Cnidocytes…. Cnidocytes…. Box Jellyfish Pale blue and transparent, difficult to see Up to 3 meter (9 feet!) tentacles Can kill within 2­3 minutes Class Anthozoa Class Anthozoa Polyp body form only All marine Many colonial E.g. sea anemones, corals Corals excrete a calcareous skeleton (Flatworms) (Flatworms) Flat bodies Triploblastic: have mesoderm Acoelomate Simple nervous system, exhibit first organ system First example of cephalization (development of head) Free living Mostly marine Four Classes Class Turbellaria Class Turbellaria Free living Have protonephridia (flame cells) osmoregulatory “Eyespots” photoreceptive neurons (ocelli) May have cilia We have a video of one feeding Class Trematoda Class Trematoda Flukes Parasitic (endoparasites) Acoelomate Complex life cycle with multiple hosts Flukes­have two suckers that attach to their host Class Cestoda (Cestoidea) Class Cestoda (Cestoidea) Parasitic Acoelomate No digestive system Body composed of multiple reproductive segments, called proglottids Scolex: attaches parasite to host, has hooks and suckers Class Monogenia Class Monogenia Fish Parasite Ectoparasties We’re not worrying about these today I couldn’t find a picture, so here’s some cool flatworms… (Roundworms) (Roundworms) Pseudocoelomates Triploblastic Complete Digestive Tract Longitudinal muscles only (whiplike movement) Dioecious (separate sexes) Excrete a thick cuticle E.g. Ascaris, trichinella, vinegar eel Roundworms Trichinosis From eating infected pork Converts human muscle cells into “nurse cells” Ascaris Ascaris Ascaris lumbridcoides : human parasite Infection begins when eggs are swallowed (so wash those hands!) Males and females have different anatomy: males tend to be smaller with a hooked tail If you want a visual guide to your dissection (as well as many other specimens in this lab), consult the plastic binder that is on your table. Parasites Parasites Phylum Arthropoda Phylum Arthropoda Most successful phylum on the planet! All possess a segmented body Head, thorax, and abdomen for insects Cephalothorax and abdomen for Cheliceriformes and Crustacea All possess jointed appendages, adapted for sensory use, walking, hopping, swimming, and more Have an open circulatory system Have a chitinous exoskeleton for protection and support Marine, freshwater, and terrestrial 4 subphylums Subphylum Cheliceriformes Subphylum Cheliceriformes Spiders, ticks, scorpions, horseshoe crabs, mites Possess chelicerae: appendages modified to be pincers or fangs Also possess pedipalps for feeding and other purposes Cephalothorax and abdomen Subphylum Myriapoda Subphylum Myriapoda Centipedes: Millipedes: One pair of legs per segment Possess fangs and are venomous Carnivorous Two pairs of legs per segment (actually each segment is two fused together) Herbivorous Both have one pair of antennae Subphylum Hexapoda Subphylum Hexapoda Body has three segments: head, thorax and abdomen Possess one pair of antennae Many, but not all, possess two pairs of wings and can fly Most successful animals on earth (90% of all animal species!!!) Tym Tym pani c Mem Mem bran e Subphylum Crustacea Subphylum Crustacea Crabs, lobsters, shrimp, crayfish, barnacles, pill bugs, etc Possess two pairs of antennae Have biramous (branched) appendages 2 part body: Cephalothorax and abdomen Number of appendages varies What could end up on the What could end up on the practical…. Slides Models Dissected specimens “Stuff in jars” Any diagrams in the book Any specimens encased in plastic Look at everything: it’s all fair game! Clean Up Clean Up Discard dissected specimens in the bucket at the end of the table. Wash your dissection trays and cross stack them. Place the slides back in the box. Discard any wet mounts you have made in the glass discard container Wash hands thoroughly!!!! ...
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This note was uploaded on 03/30/2012 for the course BIOL 112 taught by Professor Vaughn during the Fall '08 term at Texas A&M.

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