1. Porifera: Very Simple Animals...(?)
Water in, water out
Sponges bring water in through their pores and move it out through the large top opening. This current provides:
-Food
-Respiration
-Excretion
-Circulation
-Reproduction

3. -No nervous system
-Many produce toxins
-Create many symbiotic relationships (mutualism and commensalism)
Sexual Reproduction
-Sponges form both eggs and sperm
-The sperm move on current to other sponges
Asexual Reproduction
-A “bud” comes off the sponge and grows
-Produce “gemmules” in times of stress

4. Cnidarians:
-Jellies
-Hydra
-Anemones
-Corals

5. Cnidarians: Soft-bodied carnivores
Have tentacles with specialized cells called nematocysts that shoot poisonous darts into prey (p. 669)
Radial symmetry with a central mouth surrounded by tentacles
-Have two stages in their life-cycle: a polyp and a medusa. (p.670)

6. -Cnidarians paralyze prey with poison, then pull it to their mouths and into the gastrovascular cavity where it is digested.
-They have a nerve net of specialized cells that allow them to detect touch, light and gravity.
-Use a hydrostatic skeleton to contract muscles for movement.

7. -Sexual reproduction occurs through external fertilization where the zygote is a free-swimming larva
-The larva attaches to a surface and forms a polyp.
-The polyp can reproduce asexually by budding young medusae.

8. The Jellyfish: Scyphozoa (the “cup animals”)
-Range from tiny to almost 4 meters across
-Some species are extremely venomous- The box jellyfish is the most venomous animal in the world and has killed over people since the 1950s.

9. Hydra and their Relatives
-Hydras belong to the class Hydrozoa
-Most hydrozoans are colonies of polyps performing specialized functions (Portuguese Man O’ War)
-Hydra are freshwater hydrozoans that don’t have a medusa stage. They only live as polyps.

10. Anemones and Corals -This is the class Anthozoa (“flower animal”)
-Corals and anemones only have the polyp stage
-Anemones are solitary polyps
-Corals form colonies of polyps that look like tiny anemones.
-Colonies grow over thousands of years producing calcium carbonate structures that build huge reefs that are threatened.
-Corals form mutualistic relationships with algae.
-Anthozoans release clouds of sperm and eggs into the water where the zygote becomes a swimming larva before turning into a polyp.