Ch. 32&33 invertebrates

Ch. 32&33 invertebrates

1. . animal characteristics:

   • (1) multicellular (often with tissue layers)
     • (2) heterotrophic
       • (3) require oxygen (aerobic)
         • (4) reproduce sexually (some asexually too)
           • (5) Motile
             • (6) Embryonic developmental stages give rise to primary tissue layers (echo, mess, endoderm)

2. Animal Body Plans:

   • A. Invertebrate:has no back bone; vertebrates: have a backbone
     • B. Body symmetry
       • Radial: arranged around central axis; drifters
         • bilateral: anterior/posterior (cepha;ization), left/right, ventral/dorsal
           • C. Gut: for digestion/absorption of nutrients
             • sac-like:single opening for in and out
               • tubular: two openings (advantage)
                 • D. Body cavity:between gut and body wall
                   • Coelomates: have a true coelom (peritoneum encloses organs and holds in place)
                     • Psuedocoelomates: false cavity (no peritoneum)
                       • ACoelomates: have tissues between gut and wall
                         • Segmentation: repeating body units often see mostly in development
                           • Ex: earthworm has similar units; Frog has mostly different units

3. Invertebrates

   • A. Phylum Placoza (only one species)
     • two layers of ciliated cells (pita shaped)
       • no symmetry (asymmetrical)
         • no mouth ( external digestion)
           • like a single tissue organism
             • B. Phylum Porifera (sponges; 5500 species)
               • no symmetry; no tissues; no organs
                 • groups of cells form tubes with pores
                   • collar cells move water with flagella, and microvilli 'trap' food
                     • amoeboid cells continue food breakdown and distribution
                       • have 'glass-like' spicules for support
                         • release sperm (eggs stay inside to develop)
                           • C. Phylum Cnidaria (10,000 species)
                             • radial, tentacled organisms (jellyfish, sea anemones, hydra, corals)
                               • simple tissues, no organs
                                 • have medusa and polyp plans w/sac like gut
                                   • outer and inner epidermis w/ mesoglea between (jellylike...bouyancy, structure)
                                     • "nerve-net" allows sensation and motor control
                                       • nematocysts (only ones with)

4. continuation of invertebrates

   • D. Phylum Platyhelminthes
     • Flatworms: turbellarians, flukes, tapeworms
       • type of acoelomate
         • bilateral, cephalized, sac-like gut
           • hermaphroditic: can self-fertilize or exchange sperm
             • Turbellarians (planaria):
               • branched gut; protonephridia and flame cells; nervous system; reproductive system;
                 • Flukes (trematodes): parasitic flatworms
                   • has sexual and asexual stages of life cycle
                     • usually a snail or slug is a host for early stages, and a vertebrate a definitive host
                       • schistosome (blod fluke)
                         • Fluke Disease: schistosomiasis :
                           • from being in contaminated water
                             • multiply asexually in snails
                               • swimming larvae leaves snails and swim
                                 • bore into human host skin
                                   • enter veins ( thin walls)
                                     • moves to various tissues
                                       • symptoms related to tissues/organs they enter, and the immune response in that organ (s)
                                         • Tapeworms (Cestodes):
                                           • parasites of vertebrate intestines
                                             • have no gut (just absorb digest materials)
                                               • scolex:head region with hooks to attach
                                                 • proglottids:body segment units; (1) each is hermaphroditic; (2) older proglottids store eggs...break off from body and leave body in feces

5. continuation of invertebrates part 2

   • E. Phylum Rotifera
     • Bilateral, cephalized, psuedocoelomates
       • most live in fresh water; common in pond water
         • usually less than 1mmm
           • Females can produce diploid eggs, or haploid eggs that need to be fertilized by male (unusual to find male rotifers
   • F. Phylum Mollusca
     • have soft, fleshy bodies (some with shells)
       • Bilateral coelomates
         • include; Gastropods such as -snails and slugs; chitons: 8-division shells (slow moving): Bivalves: clams, mussels, oysters, scallops; cephalopods: octopus and squid
     • cephalopod anatomy: tentacles, ink jets, no shell, siphon for propulsion
       • Bivalve anatomy: two shells, foot, in and out siphon for feeding, respiration
       • Gastropod anatomy: includes full digestive system, mantle that secretes shell material (calcium carbonate and proteins), gills (ctenidia), CV system, radular mouth
   • G. Phylum Annelida
     • segmented coelomates
       • include earthworms, leeches, polychaete
         • segments usually have setae/chetae (chitin reinforced bristles)
           • anatomy includes brain, "kidney" (nephridia), CV system, digestive/GI system
             • hermaphroditic
   • H. Phylum Arthropoda
     • includes:chelicerates (spiders and relatives), crustaceans (crabs, shrimp), and uniramians (centipedes, millipedes, insects)
       • Adaptations:
         • hardened exoskeleton (chitin, protein, CaCO3)
           • jointed appendages (allows movement)
             • fused and modified segments
               • respiratory structures
                 • specialized sensory structures (eyes, antennae)
                   • division of labor:
                     • including metamorphosis (more than one body form in embryo vs adult)
                       • different morphs for different functions (allows a juvenile form to grow rapidly, an adult form to migrate for reproduction, etc)

6. continuation of invertebrates part 3

   • I. Phylum Nematoda (roundworms;20,000 species)
     • Include Ascaris, Caenorhabditis, etc
       • has a cuticle on outside
         • pseudocoelomates
           • cells absorb nutrients from coelomic fluid
             • bilateral, cylindrical, cephalized
               • complete digestive system
                 • J. Chelicerates
                   • horseshoe crabs, mites, spider
                     • anatomy includes malpighian tubules, book lungs, open circulatory system
                       • bites can be toxic (venoms of spiders or scorpion), some transmit diseases (rocky Mountain Sotted Fever or Lyme Disease: ticks)
                         • Crustaceans and Insects: Variety of shapes, habitat utilizations, variations in segmentation, head and mouth parts, etc.
   • K. Phylum Echinodermata
     • Coelomates with a combo of radial and bilateral features
       • contain spines, spicules, or plates in body wall
         • are deuterostomes (first embryonic opening becomes anus; coelom forms from gut...protostomes have mouth first, coelom from pouches in mesoderm
           • sea stars, feather stars, sea cucumbers, sand dollars, sea urchins, etc
             • have a water-vascular system for locomotion or grasping
               • decentralized nervous system