Presentation on theme: "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."— Presentation transcript:
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
-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
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)
-Cnidarians paralyze prey with poison, then pull it to their mouths and into the gastrovascular cavity where it is digested. http://www.youtube.com/watch?v=o1A5acWEERA&feature=related http://www.youtube.com/watch?v=o1A5acWEERA&feature=related -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. http://www.youtube.com/watch?v=760lUxyle6I http://www.youtube.com/watch?v=760lUxyle6I
-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.
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 5 500 people since the 1950s.
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.
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.