Osmoregulation and Gas Exchange (test 3)

Osmoregulation and Gas Exchange (test 3) - Osmoregulation...

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Unformatted text preview: Osmoregulation and Excretion Excretion of Nitrogenous Waste Ammonotelic N excreted as NH3 or NH4+ Low energy requirement Toxic High water requirement Ureotolic N excreted as urea CO(NH2)2 Intermediate energy requirement Moderate toxicity Intermediate water requirement Uricotelic N excreted as uric acid C5O3N4H4 High energy requirement Non toxic Low water requirement Excretory problems Marine to freshwater No problems Marine to land Become ureotolic or uricotelic Energy increase Freshwater to land Same as above 1 exception: isopods give off gaseous ammonia Osmoregulation problems Marine to freshwater Maintaining salt concentration higher than environment Excess water Impermeable membrane Water pump to keep nutrients and ions inside the body Marine to land Preserve water Impermeable membrane or behavioral adaptation Stick to moist environments Freshwater to land Same as above Oxygen problems Marine to freshwater Variability Moving stream-lots of oxygen, still stream-not a lot of oxygen Marine to land Maintain moist gas exchange structures; moisten them Dispersal Marine to freshwater Marine just release larvae or sperm and eggs Cant do that in freshwater or land, normally dont have larval forms Flight Direct development Marine to land Same as above Definitions Iso-osmotic Body and environment have same solute concentrations Hyper-osmotic (more) Body has higher solute concentration than environment Hypo-osmotic (less) Body has lower solute concentration than environment Osmoconformer Organism remains iso-osmotic Osmoregulator Organism able to maintain either hyper or hypo osmotic condition Euyhaline Organism able to tolerate wide range of salinities Stenohaline Organism restricted to narrow range of salinities Ionregulators and ionconformers Organism can or cannot maintain particular ions at concentrations different from environment Gas Exchange Metabolic Pathways Glycolysis Anaerobic Lactate pathway Rapid but inefficient conversion of pyruvate to lactate Used for burst work (muscle tissue temporarily, out of oxygen) 3 ATP/Pyruvate Opine pathway Rapid but inefficient Used for burst work 3 ATP/glucose Opine is a class of amino acid derivatives, slightly different ones in different organisms Succinate pathway Slower but more efficient than above Used in animals living in anoxic environments Bivalves in anoxic mud flats, endoparasites in anoxic parts of host 4-6 ATP/glucose Phosphogens Not a pathway but a class of phosphoamino acids that can store energy from ATP during periods of relaxation and deliver it under conditions of anoxia or exhaustion In order for gas to diffuse across a membrane it must be in solution; therefore, gas...
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This note was uploaded on 03/19/2008 for the course ZOL 306 taught by Professor Akins during the Fall '07 term at Michigan State University.

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Osmoregulation and Gas Exchange (test 3) - Osmoregulation...

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