Brittney

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Q: 3 Review Questions pf 987

Compare gas exchange in the following animals: A)earthworm B)Grasshopper C)Fish D)Frog E)Bird

 Gas exchange in the earthworm occurs through their body. This type of gas exchange happens in a number of animals, usually small with a high surface-to-volume ratio. In an earthworm gland cells in the epidermis secrete mucus, which keeps the body surface moist while also offering production. Oxygen present in air pockets in the soil they live in dissolve in the mucus covering them and enables them to 'breathe'. Grasshoppers, unlike the earthworm have small tubes called the tracheal tubes that run throughout the body. Grasshoppers require this specialized respiratory system because their inefficient open circulatory system cannot supply them with an efficient amount of oxygen. Air enters the tracheal through a series of twenty tiny openings called spiracles along the body surface, grasshoppers located down their backs.The hopper draws oxygen through the first four spiracles on its back during abdomen expansion, once inside the body, the air passes through the system of tracheal tubes and is later forced back out of the last six openings when the abdomen contracts. The fish uses a set of gills which are moist, thin structures that extend from the body surface. In some fish movements of the jaw and operculum help pump water rich in oxygen through the mouth and across the lungs. The water then exits through the gill slits. In each gill there are filaments which provide an extensive surface area for gas exchange. The filaments extend out into the water, which continuously flows over them. A capillary network then delivers blood to the gill filaments, facilitated diffusion of oxygen and carbon dioxide between blood and water then occurs. Frogs have ridges containing connective tissue on the inside of the lungs, thereby increasing the respiratory surface somewhat. In most reptiles the lungs are rather simple sacs, which only some folding of the wall is present to increase the surface for gas exchange. Exchanges are not very efficient and does not supply sufficient oxygen to sustain long periods of activity. In birds is the most affective respiratory system of any living vertebrate. As active, endothermic animals with high metabolic rates, birds require large amounts of oxygen to sustain flight and other activities. Their small lungs have, usually none, extensions called air sacs. These reach into all parts of the body and even connect with air spaces in some of the bones. Gas exchange doesn't occur across the walls of the air sacs.



Ambe: Great work madam! You've taught me the basics of different ways organisms take in oxygen and reasons why they've adapted to do so in that way. Twas quite lovely :)