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Phylum Porifera

Phylum Porifera. (Pore bearing) Sponges. Phylum Porifera Overview. Most primitive of the multicellular animals There is some debate if sponges are complex colonial protozoans and not metazoans Sponges Over 7,000 species 2% of all sponges are freshwater, none are terrestrial.

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Phylum Porifera

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  1. Phylum Porifera (Pore bearing) Sponges

  2. Phylum Porifera Overview • Most primitive of the multicellular animals • There is some debate if sponges are complex colonial protozoans and not metazoans • Sponges • Over 7,000 species • 2% of all sponges are freshwater, none are terrestrial

  3. Phylum Porifera Overview • Sponges occur in shallow water habitats and vary widely in size (up to 1m high) and shape • All sponges are sessile filter feeders

  4. General Characteristics • Multicellular • All aquatic- Mostly marine,some freshwater • Mostly sessile • Filter feeders • Body contains pores, canals, and chambers for water passages • Asymetrical or Radial symmetry • No head, mouth gut cavity or organs • Asexual and sexual reproduction

  5. Porifera Anatomy

  6. Pores • Ostia- incoming water • Oscula (osculum)- outgoing water

  7. Types of Cells

  8. Pinacocytes • Almost true tissue • Thin flat epithelial-type cells cover exterior and some interior surfaces

  9. Choanocytes (collar cells) • Act as a pump to bring water into the sponge

  10. Archaeocytes/ Amoebocytes • Ameboid cells that move about in the mesohyl • Functions • Phagocytize particles • Retrieve particles for digestion • Types • Sclerocytes- spicules • Collencytes-spongin • Lophocytes - collagen

  11. Sponge support • Collagen is found between the inner canals and chambers • mesohyl • Collegen is stiffened by adding microscopic mineral accretions (spicules) or additional protein fibers (spongin) or both

  12. Spicules • Skeleton structures made of calcium carbonate (CaCO3) or silicon dioxide (SiO2) • Siliceous spicules • Calcareous spicules

  13. Sponge Reproduction • Asexual reproduction • Bud formation • http://www.youtube.com/watch?v=zVv1aAJvgx0 • Regeneration following fragmentation • Somatic embryogenesis • http://www.youtube.com/watch?v=N462jZFr13k

  14. Sponge Reproduction continued • Sexual reproduction • Monoecious- have both female and male sex cells in one individual (Hermaphrodites) • Sperm arises from the transformation of choanocytes • Oocytes (eggs) arise from either choanocytes or amoebocytes • Viviparous • After fertilization the zygote is retained in the adult and derives nourishment from the parent and released as a larva • Oviparous • Oocyte and sperm are released into the water in hopes they will meet up

  15. Porifera larvae • Neighboring sponges are fertilized by sperm entering through the ostia • Ciliated mouth less larvae (parenchymella) is released

  16. Types of Sponges

  17. Asconoid: Flagellated Spongocoels • Simplest organization- Small and tube shaped • Water enters the spongocoel through dermal ostia

  18. Syconoids: Flagellaged Canals • Look like larger versions of asconoid sponges • Tube body • Singular osculum • Body wall is more complex and thicker than asconoids • Contains radial canals with choanocytes which empty into the spongocoel

  19. Leuconoids: Flagellated Chambers • Most complex sponge type • Large sponges • Numerous oscula • Clusters of flagellated chambers

  20. Classes of Sponges • Phylum Porifera • Class Calcarea(Calcispongiae) • Class Hexactinellida(Hyalospongiae)- Glass sponges • Class Demospongiae

  21. Calcarea (Calcispongiae) • Have spicules made of calcium carbonate • Mostly small in size (<15cm) and form irregular masses • Never contain spongin • Restricted to shallow water and strictly marine

  22. Hexactinellida (Hyalospongiae) • Glass sponges • Spicules are made of silica • Usually found in deep water on soft substrates in the tropics 200-1,000m • Spicules are six pointed and have a lattice-like structure • Cup, vase or urn shape

  23. Demospongiae (most sponges) • Have spicules made of silicon dioxide (SiO2) or spongin or a combination of both • Most sponges belong to this class (90%) • Mostly found on the continental shelf • Spongia spp. (Bath sponge)

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