Download Sponges & Cnidarians

Sponges &
Cnidarians
Phylum Porifera
• Sponges
– Simplest animals, multicellular
– No organs or body systems
– Asymmetry
– Cellular digestion
– Feed by filtering water
– Do not move
– Reproduce sexually and asexually
Sponge Anatomy
Osculum: large opening at top; water exits
Collar Cells (Choanocytes); layer of cells with
flagella that move water and digest food
Ectoderm: outer layer
Jellylike Cells (Amebocytes); move inside to supply
nutrients, carry away wastes, form sperm and eggs
Pore (Ostia); where water enters
Spikes (Spicules): rigid frame for support
Phylum Cnidaria
• Cnidarians (Jellyfish, Hydra, Sea Anemone, Coral,
Portuguese Man-of-War)
– Tentacles with stinging cells (Cnidocytes)
• Venom paralyzes fish (prey)
• Pull food into the mouth
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Food goes into a central cavity
Specialized tissues help them move (swim, flip, shrink, bend)
Symmetry: Radial or Asymmetry
Reproduce
• Asexually (budding)
• Sexually (both sexes in one animal or separate)
Cnidarian Anatomy
Body Plans
Polyp (stationary/vase shaped)
Medusa (swimming/cup-shaped)
Hydra
Jellyfish
Coral
Portuguese
Sea Anemone
Man-of-War
Assignment #17: Sponges
• Draw a Diagram to show how water
travels through a sponge (use arrows)
– Answer the following:
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How do pores help a sponge feed?
How do collar cells help a sponge feed?
What is the function of the osculum?
Why is a sponge classified as an animal?