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SURVEY OF THE ANIMAL KINGDOM

SURVEY OF THE ANIMAL KINGDOM. PHYLUM PORIFERA. OVERVIEW Most primitive of the metazoans Over 7,000 species, approximately 40 species that occur in local waters 2% of all sponges are freshwater, none are terrestrial

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SURVEY OF THE ANIMAL KINGDOM

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  1. SURVEY OF THE ANIMAL KINGDOM

  2. PHYLUM PORIFERA • OVERVIEW • Most primitive of the metazoans • Over 7,000 species, approximately 40 species that occur in local waters • 2% of all sponges are freshwater, none are terrestrial • Sponges occur in shallow water habitats and vary widely in size (up to 1 meter high) and shape • All sponges are sessile filter feeders

  3. PHYLUM PORIFERA • CHARACTERISTICS • Cellular level of organization, without true tissues • Adults exhibit radial symmetry or are asymmetrical • Possess totipotentcells • Possess unique flagellated cells (choanocytes) that create water flow through a water current system

  4. PHYLUM PORIFERA • CHARACTERISTICS • Outer and inner cell layers lack a basement membrane • Outer and inner cell layers divided by a noncellular layer (mesohyl) that contains some cells and skeletal material --- collagen • Body support (“skeleton”) provided by spicules composed of calcium carbonate (CaCO3)or silicon dioxide (SiO2)

  5. PHYLUM PORIFERA • AMOEBOCYTES • Located in the mesohyl, with different roles • Phagocytic – role in digestion • Archeocytes– totipotent • Sclerocytes– spicule production • Spongocytes– secrete spongin • Collenocytes– collagen of mesohyl

  6. PHYLUM PORIFERA • REPRODUCTION • Asexual budding • Regeneration from broken pieces • Sexual • Hermaphroditic (some dioecious) • Eggs --- archeocytes or choanocytes • Sperm --- choanocytes • Neighboring sponges are fertilized by sperm entering through the ostia

  7. PHYLUM PORIFERA • CLASSIFICATION • Class Calcarea • Class Demospongiae • Class Hexactinellida

  8. PHYLUM PORIFERA • CLASS CALCAREA • Have spicules made of calcium carbonate • Mostly small in size (<15 cm), and form irregular masses • NEVER contain spongin, restricted to shallow water, and strictly marine

  9. PHYLUM PORIFERA • CLASS DEMOSPONGIAE • Have spicules made of silicon dioxide or spongin or combination of both • Most sponges belong to this class (90%) • Mostly found on the continental shelf • Spongiaspp. (bath sponge)

  10. PHYLUM PORIFERA • CLASS HEXACTINELLIDA • Spicules are made of silica • Usually found in deep water on soft substrates in the tropics 200-1,000 meters • Spicules are six pointed and have a lattice-like structure • Cup, vase or urn shape • Euplectellaspp. (deep sea glass sponge)

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