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Sponges and Cnidarians

This article provides an introduction to sponges and cnidarians, including their origins, evolution, and characteristics. It explains the diversity of sponges, their different body types, and methods of reproduction. It also discusses the characteristics of cnidarians, their two basic body forms, and their life cycle.

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Sponges and Cnidarians

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  1. Sponges and Cnidarians

  2. Sponges

  3. Sponges Intro. • Origin • Evolution: believed to have evolved from protists • Collar cells: are almost identical to many flagellated protist cells • Uses of collar cells: • Move water, ingest food and excrete waste

  4. Sponges Intro, cont. • Diversity • Species #: 8300 • Variety: • 3% live in freshwater • Variety of shapes, sizes and colors • Live at a variety of sea depths

  5. Characteristics of Sponges • KingdomAnimalia • PhylumPorifera • They are mostly marine (live in salt water) • # of cells: multicellular • Body contains pores, canals and chambers that allow for water flow

  6. Characteristics of Sponges • Symmetry: radial • Interior surface: lined with collar cells (choanocyte) • Choanocyte: • a flagellated collar cell that lines the inner surface of sponges

  7. Choanocyte • Beating flagella • Create water current • Capture food and water particles • Carries away waste

  8. Choanocyte • Collar is made of microvilli • Why? To create a filtering device to collect food

  9. Choanocyte • The food particles then become trapped • How? Taken in by the food vacuoles (where they are stored and digested)

  10. Food and Oxygen Exchange • Efficient? Non-efficient? • Why? • Lots of collar cells working together

  11. Structure of a Sponge • Made of ? • Spicules – calcareous or siliceous, support structures • Spongin – fibrous proteins, made of collagen

  12. Spicules

  13. Spongin Fun fact: When you wash with natural sponges, this is the portion you wash/exfoliate with!

  14. Spicules & Spongin

  15. Characteristics of Sponges • Reproduce asexually or sexually • By? Budding or gemmules (asexual), sperm and egg (sexual) • Larva: motile, move • Adults: sessile, don’t move Sponge Love Scene #1 Sponge Love Scene #2 Sexual Budding

  16. Gemmule

  17. Three Main Body Types 1. Asconoid • Def: one large body cavity • Characteristics: • Collar cells line the main body cavity • Contain many pores

  18. Three Main Body Types 2. Syconoid • Def: many canals, water flows through each canal • Characteristics: • Collar cells line canals • Can filter more water

  19. Three Main Body Types 3. Leuconoid • Def: contains chambers • Characteristics: • collar cells line chambers • Often used for shower sponges

  20. Classification of Sponges • Kingdom: Animalia • Phylum: Porifera • Class Calcarea • Class Hexactinellida • Class Demospongiae

  21. Class Calcarea • Spicules • Made of calcium carbonate (like baking soda) • Shape: needle shaped, 3-4 sections/rays • Body types? • All three types represented

  22. Class Hexactinellida • Spicules • Made of? Silica (glass-like) • Description: Six sections/rays • Body types? Asconoid or leuconoid • Often called? • Glass sponges

  23. Class Hexactinellida

  24. Class Demospongiae • Spicules • Made of: silica • Description: don’t have 6 rays • Body types? Leuconoid only • Other characteristics: • Make up 95% of all sponges • Use this type in bath/shower

  25. Class Demospongiae

  26. Cnidarians

  27. Characteristics of Cnidarians • Kingdom Animalia • Phylum Cnidaria • Examples: • Hydra, sea anemone, jellyfish, Portuguese-man-o-war, moon jelly, sea pen, coral • Where do they live??? • Almost entirely aquatic (mostly marine/salt-water)

  28. Characteristics of Cnidarians • Symmetry: Radial or biradial • Head region? No definite head region • Two basic types: • Name, def, examples • Polyp: tentacles facing upwards • Ex: sea anemone, coral • Name, def, examples • Medusa: tentacles facing downwards • Ex: jellyfish, man-o-war

  29. Polyp Form • Polyp – • Lifestyle of polyps? Sessile (do not move) • Body shape? Tubular (tube-like) • Mouth: Surrounded by tentacles (facing up)

  30. Medusa Form • Medusa – • Lifestyle? Mobile/motile (move) • Body shape? Umbrella shaped • Mouth : surrounded by tentacles that face downwards

  31. Life Cycle • Body forms? Most cnidarians exist as BOTH body forms at some point during their life cycle • Reproduction • Polyp: reproduce asexually using budding • Medusa: reproduce sexually using sperm/egg

  32. Life Cycle

  33. Characteristics of Cnidarians • Two layered body • Epidermis – • Def: outer part of the body • Derived from? Ectoderm • Gastrodermis – • Def: inner part of the body • Derived from? Endoderm • Lines the gut cavity • Main function: digestion

  34. Characteristics of Cnidarians

  35. Characteristics of Cnidarians • Tentacles contain cnidocytes • Function: aid in capture of prey/food • Characteristics: armed with nematocysts • Nematocyst: stinging cell (contains hook/barb used to catch)

  36. Nematocyst • Stinging cells • Contain filament • When do they uncoil? When they are touched by animals (in the environment) • Contain barb or spine • Poisons can be injected

  37. Nematocysts Nematocyst Firing

  38. Four Classes of Cnidarians • Class Hydrozoa • Class Scyphozoa • Class Cubozoa • Class Anthozoa

  39. Class Hydrozoa • Solitary (live as an individual) • Colonial (live in groups) • Reproduce? Asexually (Polyp form) OR sexually (medusa form) • Where do they live? Freshwater OR marine/salt-water • Examples: Hydra, Tubularia

  40. Hydra

  41. Obilia Medusa Polyp

  42. Physalia

  43. Class Scyphozoa • Movement: Solitary (live by themselves, but MOVE quiet a bit) • Body form: Medusa form (most) • Where do they live? All marine/salt-water • Organs? Sensory organs found on the ridge of the umbrella • Examples: Cassiopeia, Aurelia

  44. Aurelia

  45. Cassiopeia

  46. Class Cubozoa • Movement: Solitary (live by themselves but MOVE quite a bit) • Body form: Medusa form (most) • Where do they live? All marine/salt-water • Characteristics? Umbrella is more square in shape • Examples: Tripedalia, Carybdea

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