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Echinodermata

Mia Lybkær Kronborg Nielsen Structure and Function of Marine Invertebrates Bachelors English 30 cards

Cards in this deck (30)

  1. 1Defining characteristics- Water Vascular System (WVS)
    - Secondary radial symmetry (larvae is bilateral symmetrical)
    - Endoskeleton formed by calacareous ossicles made by the mesodermally-derived tissue
    - "mutable" connective tissue
  2. 2General characteristics- all species are marine
    - deuterostomes
    - the free larvae is bilateral symmetrical
    - most adults are pentamerous
    - no cephalization (no distinctive head)
    - body surfaces either aboral or oral (without mouth or with mouth)
  3. 3Water Vascular system: structue- internal canals that are linked to the outside sea-water through the madreporite
    - ring canal in center from where the radial tubes protrude one in each arm
    - from the radial tubes runs lateral tubes where the tube foot is placed (oral side) as well as ampullae (aboral side)
  4. 4Water Vascular system: the five functions- gas exchange
    - locomotion
    - excretion (through tube feet)
    - circulatory system (together with other coelomic compartments)
    - some groups: chemoreception and food collection
  5. 5Water Vascular system: How does it function for the locomotion?- From the lateral tube there are one-way valves that can close, so water doesn´t run back into the radial tubes when the ampullaes are compressed
    - ampullae presses or sucks water into/out of the tube feet, altering their size
    - retractor muscles move foot in the wanted direction
    - duo-glands make sure the foot sucks to surface or release
    - suction disc at end of tube foot also makes the foot stick to surface
  6. 6Radial symmetry- is secondarily derived
    - larvae is bilaterally symmetrical
    - no cephalization
  7. 7Endoskeleton- mesodermallly-derived tissue make the calcareous ossicles
    - the calcareous ossicles are intra-cellularly produced and are covered by a thin epithelium
  8. 8"Mutable" connective tissueThe viscocity of the connective tissue can change rapidly and is under direct control of the nervous system.
    The mechanism of this invovles polymerization and depolymerization of macro-molecules (e.g. collagen)
  9. 9"Mutable" connective tissue: What is the function of the depolymerization of the connective tissue?It can be used in "arm casting" (=moving the arms flexibly) and "evisceration" (=expelling internal organs as a defense mechanism seen in sea cucumbers)
  10. 10"Mutable" connective tissue: What is the function of the polymerization of the connective tissue?It can be used for wedging into small crevices for protection and for opening bivalves
  11. 11Which structure is associated with respiration and excretion?The tube feet and dermal papulae (outfolds of epidermis)
  12. 12Which structure is associated with the circulatory system?WVS and other coelomic compartments, such as the main body cavity and the hemal system
  13. 13What is coelomocytes and what are their functions?They are specialized cells found in tissue and body fluids:
    - recognize and phagocytize foreign materials
    - synthesize collagen
    - transport oxygen
    - phagocytizing food particles
  14. 14What are the main classes and subclasses?Crinoidea
    Stelleroidea
    - Ophiuroidea
    - Asteroidea
    Echinoidea
    Holothuroidea
  15. 15What are the two groups of animals within the Crinoidea (Sea Lily)?- sea lilies: stalked, sessile
    - feather stars: non-stalked motile, have cirri
  16. 16What feeding habits do the animals in the class Crinoidea have?Suspension feeders: intentionally catch food particles from surrounding water with structures that are specialized for this function
  17. 17What structure is related to the feeding habit in the Class Crinoidea?The arms and grooves: the pinnules on the arms lead the food particles to the groove where cilia leads the food to the mouth and mucus glands secrete mucus that entangle the food particles
  18. 18What are some characteristics that set the class Crinoidea apart from the rest?- no madreporites
    - a group are stalked and non-motile
  19. 19Class Stelleroidea: Defining characteristics- oldest class in phylum
    - have primitive characteristics
    - arms present in multiple of 5 and extend from the central disc
    - the digestive system is tubular with a mouth and anus
  20. 20Class Stelleroidea: subclass Ophiuroidea (brittle stars): Defining characteristics- ossicles in arms are well developed and jointed, forming "vertebrae"
    - bursal slits on oral surface, which can be used for gas exchange and brooding
    (G.C: anus absent)
    OBS: differ from sea stars by primarily using its arms for locomotion
  21. 21Class Stelleroidea: subclass Ophiuroidea: feeding habitsdeposit or suspension feeders
  22. 22Class Stelleroidea: subclass Ophiuroidea: what are the structures for protection on the animal?- oral surface body disc: thin layer of minute, calcareous scales
    - aboral surface bears a number of shields
  23. 23Class Stelleroidea: subclass Ophiuroidea: what are the functions of the shields on the aboral side of the animal?- protection
    - in some species the surface of the shields form lenses that focus light on underlying nerves
  24. 24Class Stelleroidea: subclass Asteroidea: some general characteristics- gonads and parts of digestive glands extend into the arms
    - differ from the brittle stars by primarily using the tube feet for locomotion and they move slower than the brittle stars
  25. 25Class Stelleroidea: subclass Asteroidea: some characteristics of the digestive system- mouth towards substrate, anus towards surface
    - three parts: cardiac stomach (digestion), pyloric stomach and pyloric caeca (both for secretion of enzymes and absorption)
    - can protrude the cardiac stomach and digest prey externally
  26. 26Class Stelleroidea: subclass Asteroidea: AutotomizationA chemically induced process where the animal can cast of its arms when distressed or attacked
  27. 27Class Echinoidea (sea urchins and sand dollars): Defining characteristics- ossicles are jointed to form a rigid test
    - podia pores pass through ambulacral plates
    - Aristotle´s lantern: comples system of ossicles and muscles, that surrounds the esophagus and is used for grazing and chewing
    - stomach not protrusible
  28. 28Class Holothuroidea (sea cucumbers): Defining characteristics- worm-shaped body and elongated on oral-aboral axis
    - ossicles are reduced in size and embedded in the body wall (make up large portion of dry weight)
    - highly branches, muscular respiration structures (respiration tree) that extends from the cloaca into the coelomic cavity
  29. 29Class Holothuroidea: feeding habitsdeposit feeder:
    can ingest over 130 kg of substrate per year
  30. 30Class Holothuroidea: what is a difference in the WVS compared to the other classes?WVS is present, but not connected to the outside

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Bachelors Structure and Function of Marine Invertebrates Flashcards on Echinodermata, created by Mia Lybkær Kronborg Nielsen on 25/11/2015.
Created by
Mia Lybkær Kronborg Nielsen · Nov 2015
Updated
Feb 19, 2016
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