1 / 13

Sponges and Cnidarians

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

jewel
Download Presentation

Sponges and Cnidarians

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Sponges and Cnidarians Biology 112

  2. 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)

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. Cnidarians and body structure • Possess a hydrostaticskeleton • Consists of layers of circular muscles as well as longitudinal muscles that, with the digestive cavity, allow it to move

  10. Cnidarians and reproduction • Asexual – by budding • Sexual – external fertilization in water

  11. 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

  12. Portuguese man-of-war

  13. Coral reefs

More Related