Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
SPONGES AND CNIDARIANS BIOLOGY 112 SPONGES • • • • • Phylum Porifera Multicellular and heterotrophic No cell wall and few specialized cells Live their entire life attached to a surface They eat by sifting microscopic food in water • Choanocytes are specialized structures that help move water through their body cavity • Water enters through pores and leaves through the osculum (a large hole at the top of the cavity) GETTING EVERYTHING IT NEEDS • Digestion is intracellular • Takes place inside the cells • Not only is food provided using this sifting action but also everything for respiration, circulation and excretion SPONGES AND REPRODUCTION • Reproduce sexually and asexually • Sexually • Eggs are fertilized internally • Zygote develops into a larva • Larva is the immature stage of the organism that looks different from the adult • They are motile • Carried by the ocean to the floor and grow into an adult sponge • Asexually • By budding CNIDARIANS • Phylum Cnidaria • Soft-bodied carnivores that have stinging tentacles arranged in circles around their mouth • Simplest animals that have body symmetry and specialized tissues • Exhibit radial symmetry • Central mouth with several tentacles TWO DISTINCT LIFE STAGES • Polyp • Cylindrical body with arm-like tentacles and usually do not move • Lives attached to the surface with its mouth pointing upward • Medusa • Bell-shaped body with a mouth at the bottom • Free swimming CNIDARIANS AND DIGESTION • Possess a gastrovascular cavity • Digestive chamber with one opening • Foods and wastes enter and leave this opening • Nutrients are transported throughout body by diffusion • Oxygen and wastes are diffused through the body walls CNIDARIANS AND RESPONSE TO STIMULI • Gather information from their environment using specialized sensory cells • nerve nets • a network of nerve cells that together let cnidarians detect stimuli CNIDARIANS AND BODY STRUCTURE • Possess a hydrostatic skeleton • Consists of layers of circular muscles as well as longitudinal muscles that, with the digestive cavity, allow it to move CNIDARIANS AND REPRODUCTION • Asexual – by budding • Sexual – external fertilization in water CLASSIFICATION OF CNIDARIANS • Jellyfish • Live mostly as medusas • Hydras • Grow in branching colonies • Ex. Portuguese man-of-war • Sea Anemones and Corals • • • • • Only have a polyp stage Colonial Polyps grow together in large numbers Secrete an underlying skeleton of calcium carbonate Form coral reefs PORTUGUESE MAN-OF-WAR CORAL REEFS