BIO 203 Lecture Notes - Lecture 5: Tonicity, Fruit Preserves, Thermoregulation
16 Nov 2016
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An animal that maintains a stable bfoc despite osmotic stress. An animal whose bfoc tracks environmental osmotic concentration. An animal that can survive over a wide range of environmental osmotic concentrations. An animal that can tolerate only a limited range of environmental osmotic concentrations. Most osmoregulators with a bfoc of ~300 mosm. Water and ion regulation are linked because: Movement of solutes typically leads to the movement of h2o. Osmolarity depends on both the amount of ions and the volume of h2o. Factors to consider in terms of h2o/ion balance. Affect passive gain/loss and to maintain balance, need to be dealt with using regulated gain/loss. Respiration - major source of passive h2o loss. What makes respiratory surfaces efficient o2/co2 exchangers also make them sources of h2o/ion loss. Reptiles/desert amphibians/birds & most mammals - skin highly impermeable to water. Humans - somewhat of an exception - sweating. Ex: seal eating marine invertebrates (isosmotic; 1000 mosm) v. fish (300 mosm)
