Echinodermata Flash Cards

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Title: Echinodermata
Description: Zoology Echinodermata characteristics
Number of Cards: 35
Save Count: 0
Author: pretty_indi0511
Created: 2007-12-14
Tags: echinodermata zoology
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    • Question
    • Answer
    • Side 3
    • Echinodermata
      General
    • - No heads (cephalization)
      - No eyes
      - No sense direction
      - Radial symmetry
      - Oral and aboral surfaces
    • Echinodermata
      Characteristics
    • - 6500 ssp.
      - 13000 fossil ssp
      - Only marine
    • Echinodermata
      Classification
    • Class Stelleroidea
      - Subclass Asteroidea (Sea star)
      - Subclass Ophiuroidea brittle star)
      Class Echinoidea (Sea urchin, sand dollar)
      Class Holothuroidea (sea cucumbers)
      Class Crinoidea (Sea lilies)
    • Echinodermata
      Apomorphy
    • - Pentamerous radial symmetry
      - Water vascular system
      - Mutable connective tissue
    • Echinodermata
      Body covering and skeleton
    • - Epidermis, dermis (derived from mesoderm)
      - Dermis with ossicles
      - Muscle layers beneath dermis
      - Tubercles and spines
      - Pedicellaria (pincer like structures, respond to stimuli)
      - Papulae (gas xchange)
    • Echinodermata
      Pedicellaria
    • - For removal of debris, settling larvae
      - Produce toxin
      - Hold materials for camouflage
    • Echinodermata
      Water Vascular System
    • - Internal canals and closed extensions.
      - Derived from coelom, outpouching from digestive tract into 3 chambers
      - Madreporite
      - Stone canal leads to ring canal with many radial canals.
      - Extensions to outside through podia (tube feet)
    • Echinodermata
      Tube Feet
    • - Composed of muscle
      - Thin
      - Gas exchange surfaces
      - Adhesive/glue (dual gland system)
      - Extend to outside via ambulacral grooves
    • Echinodermata
      Mutable connective tissue
    • - Change rigidity rapidly from hard to soft
      - Used as defense, autotomy (arm of sea star breaks off) and evisceration (burp out internal organs of sea cucumber).
      - Hardening for spine locking and feeding.
    • Echinodermata
      Hemal System
      Morphology
    • - Separate set of flid filled channels
      - Ring and radials
      - axial organ
      - Possibly used to transport fluids from the coelomic fluid to the gonads
    • Echinodermata
      Hemal system
      Function
    • - Nutrient transport
      (Experiment done with radioactively labeled food)
      - Axial organ with excretory function
      - Produce coelomocytes (immune system)
    • Echinodermata
      Nervous System
    • - Decentralized, diffuse
      - No brain
      - Three nerve networks and a nerve net
      - Ectoneural - sensory stimuli
      - Hyponeural - motor function
    • Echinodermata
      Digestive System
    • - Predators, grazers, filter/suspension feeders
      - Full functioning digestive tract
    • Echinodermata
      Reproduction and Development
    • - Asexual (limited)
      - Sexual, dioecious
      - External fertilization
      - Indirect via planktonic larvae
      - Direct via brooding of young.
    • Echinodermata
      Origin of penta radial symmetry
    • - Developmental regulatory genes, specify anterior-posterior parts.
      - Lowe and Wray used 'engrailed' gene.
      - Found 'engrailed' gene in each arm (normally expressed anterior to posterior in bilateral animals)
      - Like one animal grew 5 bodies...
    • Class Crinoidea
    • - Feather stars, sea lilies
      - Most ancient
      - 700 ssp.
    • Class Crinoidea
      Morphology
    • - Body on stalk or stalkless w/ claws
      - Mouth and anus upwards (U shape)
      - Crown is pentamerous
      - Stalk is retained in sea lilies
      - Stalk is lost post larval development of feather stars
    • Class Crinoidea
      Stalks..
    • - Protective calcareous plates on outter surface
      - stalk looks jointed
      - Cirri on stalk
      - Used for grasping substrate
    • Class Stelleroidea
      Characteristics
    • - All armed echinoderms
      - 2 subclasses
      - Arms are 5 or 5x from central disc
    • Subclass Asteroidea
      Characteristics
    • - 1800 ssp.
      - Sea Star
      - Arms not distinct from central disc
      - no rapid movement
      - Predators
    • Subclass Asteroidea
      Specifics
    • - Gonads and digestive tract extend into arms
      - 2 stomachs (pyloric and cardiac)
      - Can evert stomach to feed
      - pedicellariae
      - Distinct ambulacral grooves
    • Subclass Ophiuroidea
      Characteristics
    • - 2100 ssp.
      - Marine
      - Brittle stars, basket stars
      - All are motile, fast/rapid
    • Ophiuroidea
      Specifics
    • - Arms sharply set from central disc (may be branched)
      - Arms solid, appear jointed
      - Podia have no role in locomotion
      - Surfaces w/ plates or sheilds
      - Vertebra (internal ossicles, each set of sheilds)
      - podia are tentacle like
      - no papulae, no pedicellariae and no anus.
    • Class Echinoidea
      Characteristics
    • - Sea urchins, sand dollars
      - 1,000 ssp.
      - Oval/spherical shape w/ no arms (spines instead)
      - Flattened body on oral/aboral surface
      - Rigid tests
      - two groups: Regular and Irregular
      - 7000 shared genes w/ humans
    • Echinoidea
      Regular
    • - Radial
      - Sea urchins
      - Epifaunal, live and move on sea floor
    • Echinoidea
      Irregular
    • - Bilateral
      - Heart urchines, sand dollars
      - Infaunal, burrowing
    • Echinoidea
      Locomotion
    • - Spines
      - Tube feet
      * Also used for "non locomotion" to brace themselves in place
    • Echinoidea
      Aristotles Lantern
    • - Specilized scraping apparatus
      - 5 calcareous plates
      - Pointed end toward mouth
      - only in sea urchins and sand dollars
    • Echinoidea
      Feeding
    • - Urchins: graze and scrape substrate
      - Heart urchins: burrow, slective deposit feeders.
      - Sand dollars: just beneath surface of sand, pick up particles w/ podia
    • Echinoidea
      Spines
    • -Long thin and sharp or thick and round
      - Toxins associated w/ spines
    • Class Holothuroidea
      Characteristics
    • - Sea cucumbers
      - 1200 ssp.
      - Suspension and deposit feeders
      - Abyssal habitats (ocean floor below 2000 meters)
    • Holothuroidea
      Morphology
    • - Stretched sea urchin, elongate tube
      - No arms
      - Modified podia around mouth, tentacles (part of WVS)
      - Ossicles reduced
    • Holothuroidea
      Gas Xchange
    • -Respiratory trees: system of tubules, highly branched, filled with water
      - No trees in pelagic or benthic species, gas xchange through tube feet.
    • Holothuroidea
      Evisceration
    • loss of internal structures, via mutable tissue. Can regenerate.
    • Echinodermata
      Ecology
    • - Economic and ecological importance
      - Decimate sea weed/grass. Distroy fish habitat.
      Starfish destroy coral reefs
      - Major predator of molluscs
      - Otters are keystone species. W/o otters, urchins overpopulate and destory kelp forests.