BMS1021 Lecture Notes - Lecture 14: Depth Perception, Thumb, Neutral Buoyancy
8 Jul 2013
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Diploblastic which means they have two germ (cell) layers. Oxygen and waste are diffused across body (no organs necessary for these tasks are carnivorous and use tentacles (armed with cnidocysts) to catch their prey gastrovascular cavity is used for digestion (mouth/anus same) Have bilateral symmetry and triploblastic development (3 germ layers) Members of this phylum known as flatworms. Bilaterally symmetrical, triploblastic (three germ layers) and are acoelomates. Flatworms have a gastrovascular cavity but lack respiratory and circulatory systems. Plays an important role in circulation, excretion, and movement. Body plan consists of a segmented body, hard exoskeleton, and jointed appendages. Body of an arthropod is completely covered by the cuticle an exoskeleton made of layers of protein and the polysaccharide chitin. Advantages of an exoskeleton: rigid support for muscles, protection, hard jaws. Disadvantages of an exoskeleton: that arthropods must moult to grow which is energy costly and dangerous. Places a limit on the maximum size an arthropod can grow.
