Biology 2601A/B Lecture Notes - Lecture 18: Water Mass, Periplaneta, Tonicity
6 Mar 2018
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Lecture 18 - water balance in terrestrial animals. In terrestrial habitats there is a huge variation in the availability of water: this provides us with some of the variation to understand how animals survive in terrestrial environments. Insects: arachnida, chordata, only tetrapods birds and mammals and reptiles, not many terrestrial fish. It can get water from: drinking, food, metabolic water in food, absorption (water vapour) through their butts. It can lose water: through breathing, evaporation, urine, faeces. How to survive in desiccating (i. e terrestrial) environments: carry more water (water bottle, or collect it along the way, absorbing water up thee butt in the beetle, survive losing more water, lose water more slowly. Females are better because they are actually bigger so they can carry more water: the d-flies have been selected for dehydration tolerence. In the males they go from surviving about 8 hrs to surviving about 20 hrs. Lots of hydroxyl groups = a lot of binding to water.
