BIO120H1 Lecture Notes - Lecture 16: Osmoregulation, Metabolic Water, Aestivation
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BIO120H1 Full Course Notes
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Two reasons why natural selection produces deeply imperfect organisms: tradeoffs: being good at x may necessarily imply being bad at y, constraints: selection builds on what is already there, especially existing developmental programs (tinkering, not fundamentally fresh redesign) Regulatory problem that animals have: in addition to maintaining heat balance, have to maintain osmotic balance. Mostly made of water, physiology depends on reactions that take place in aqueous solution. Don"t work if solution too saline or too dilute. Getting rid of overload water: kidneys and colon. K-rat tactics for conserving water in hot, dry environments: interaction of morphology, physiology, and behaviour: anatomy: erect posture, bipedal; less heat gain from ground. Keeps from getting too much conductive heat from hot desert substrate (sand) Fewer points of contact to pick up heat from environment. Long tails and big ears shed heat: physiology: osmoregulatory system.
