Presentation on theme: "Porifera: Very Simple Animals...(?)"— Presentation transcript:
1 Porifera: Very Simple Animals...(?) Water in, water outSponges 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 spongesAsexual Reproduction-A “bud” comes off the sponge and grows-Produce “gemmules” in times of stress
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.