16B (bio)

• Sponges


  Invertebrates that are multicellular, eukaryotic, asymmetrical, and sessile
• Sponges

  • Develop from zygotes
  • Phylum Porifera
• Sponge structure

  • Tubes with only one open end
• Collar cells


  Flagellated cells that line the inside of the sponge and beat vigorously to create currents through the sponge
• Osculum


  Structure that ejects waste products into the current created by the collar cells
• Digestion in sponges


  1. Nutrients are absorbed directly through the body wall

  2. Some sponges have specialized cells for digestion
• Cnidarians


  • Radially symmetric bodies that ripple
  • Examples: jellyfish, sea anemones, corals
• Coral bleaching

  Caused by rising sea temperatures and excess fertilizer runoff, leading to loss of symbiotic algae and coral death
• Sponges and algae mutalism

  Algae provide protection and some nutrients for sponges, while sponges provide a habitat for the algae
• Symbiotic algae do not form reefs, only corals that host the algae can form reefs
• spicules are spiky stiff structures that support the wall of sponges
• cells that transports nutrients in the sponge create spicules
• some sponges are softer and will contain spicules and a spongier structure called spongin
• collar cells are flagellated cells that line inside the sponge and are responsible for the movement of water
• how do collar cells create a current through the sponge?

  they beat vigorously
• osculum is where waste products are ejected into the water current
• cnidarians reproduce asexually by budding and dividing themselves into half
• because of asexual reproduction, many polyps live on one exoskeleton and are all genetically identical
• cnidarians reproduce sexually more often
• cnidarians reproduce sexually when ..

  1. male releases sperm into the ocean and fertilizes an ova released by a female
  2. becomes a zygote
  3. cells of zygote multiply until a hollow blastula is formed
  4. blastula develops into larval form
  5. larval form matures into polyp or medusa form
• parasitic sponges and cnidarians

  sessile and choose free swimming hosts
• sponges, sea anemone, fish, jellyfish, and other corals find food and shelter on coral reefs
• coral reefs protect beaches from wave erosion