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Porifera: Very Simple Animals...(?)

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Presentation on theme: "Porifera: Very Simple Animals...(?)"— Presentation transcript:

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.


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