BIOL108 Lecture Notes - Lecture 20: Gastrovascular Cavity, Hydrostatic Skeleton, Intracellular Parasite

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Lien Luong

Document Summary

Eumetazoan; have true & differentiated tissues radial symmetry (mostly) Diploblastic = two layers (ecto- and endoderm) Organs: collections of tissues specialized for different tasks. What organisms do they include? jellyfish, hydras, sea anemones, corals. Oral end upwards, attached to a substrate. Oral ends downwards, moves freely through the water via hydrostatic skeleton they also have a gastrovascular cavity but it is not a coelom. Cnidarians are carnivorous they are known for their unique cells; cnidocytes. Each cnidocyte contains very complex endocellular structure- most common type is nematocyst. Use cnidocytes to defense & prey capture. A touch-sensitive trigger; launches the nematocyst when it comes into contact with something else. Nutrients absorbed by nearby cells (no need for bulk transfer) Some cnidarians" toxins are dangerous to humans. Portuguese man-o"war ; floating hydrozoan colony important for human economy. E. g. tourism for coral reefs runoff from farming & global warming.