Bio 2.2 Porifera (Sponges)

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Bio 2.2 Porifera (Sponges)
2013-01-30 21:49:19
labexam1 bio22 spring2013

Show Answers:

  1. What is an animal?
    A multicellular, eukaryotic heterotroph.
  2. What is a sponge?
    An asymmetrical filter feeder found in marine and fresh water environments, flourish in warm shallow salt water lagoons.
  3. What is a sponge made of?
    Calcium or silicon spicule framework with weaves of spongin protein throughout its body.
  4. What molecular features are necessary for multicellularity to occur?
    Cell adhesion proteins and signal transduction pathways for processing environmental and cellular signals.
  5. What are the four cell types used by porifera?
    • Choanocytes
    • Archaeocytes/Amebacytes
    • Pinacocytes
    • Sclerocytes
  6. Choanocytes
    Flagellated cells that create an incurrent of water. Have a sturdy mesh-like collar at the base of the flagellum.

    Flagellum spins, pulling water through the collar and food gets trapped. 

    Small food particles can be directly endocytosed into choanocyte.
  7. Archaeocytes/Amebacytes
    Move among the choanocytes phagocytizing and digesting larger food particles trapped in the choanocyte collars.

    Can also differentiate into other cell types.
  8. Gemmules
    A small packet of archaeocytes that can be released in a form of asexual reproduction.
  9. Pinacocytes
    Tough flat cells that cover the organism or line canals opening directly to the outside environment.
  10. Sclerocytes
    Secrete a skeleton-like framework (either crystals of calcium carbonate or spongin) for the organism.
  11. What are the three basic canal types used by sponges?
    • Asconoid
    • Syconoid
    • Leuconoid
  12. Asconoid Body Type
    Simple, vase like structure. Water enters pores on the surface and passes over one layer of choanocytes.
  13. Synconoid Body Type
    Folded wall into radial canals. Water flows through the canals.
  14. Leuconoid
    Folded wall canals with chambers that allow more water to pass through and more food to be collected.
  15. What are the three major classes of sponges?
    • Calcarea
    • Hexactinellida
    • Demospogiae
  16. Calcarea Sponge
    Reinforces itself with spicules of calcium carbonate.
  17. Hexactinellida Sponge
    Uses 6-rayed spicules of silicon dioxide (glass).
  18. Demospogiae Sponge
    Also uses spicules silicon, but the major skeletal reinforcement for them is spongin protein.

    Example: Harvested sponges.
  19. Spongocoel
    Hollow cavity running up the middle of the sponge.
  20. Incurrent canals
    Canals that open to the outside of the sponge
  21. Radial canals
    Canals that open to the spongocoel of the sponge and gather food.
  22. Dermal ostia
    Small openings in the sponge that lead food-laden water from the environment into the incurrent canals.
  23. Prosopyle
    Opening that leads water coming from the incurrent canals to the radial canals and filters the water.
  24. Apopyle
    Filtered water from the prosopyle passes through this to the spongocoel.
  25. Osculum
    Water and cellular waste let out of the sponge through this opening.
  26. What path does water and nutrients take in a sponge?
    Beginning through the dermal ostia it goes through incurrent canals through the prosopyle (filter) to the radial canal, through an apopyle into the spongocoel and out the osculum.
  27. How to sponges reproduce?
    Asexually and sexually.
  28. Asexual reproduction (Gemmulation):
    Fragments break off and land in a suitable environment to attach and grow.
  29. Sexual reproduction:
    Sperm cells of one sponge are captured by choanocytes from another sponge and used to fertilize its eggs. This results in a zygote that divides to form a ball of cells called amphiblastula larva.
  30. What is an amphiblastula larva and how does it feed/move?
    It is a divided zygote of a fertilized sponge egg which contains both archaeocytes and differentiated choanocytes. 

    It feeds by orienting its flagella inward. It moves by orienting its flagella outward.