BIOL 3114 Lecture Notes - Lecture 14: Water Scarcity, Subcutaneous Tissue, Aestivation
2 Nov 2016
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Document Summary
Amniotic egg allows larger eggs/offspring evolution of larger body size. Waterproof skin and costal lung ventilation eliminated reliance on humid microclimates. Allows evolution of high levels of sustained activity: synapsida mammalia, sauropsids archosauria (dinosauria and aves) High activity levels require adaptations: increased metabolic rates evolution of endothermy, changes in locomotor styles, improved lung ventilation, improved processing of nitrogenous wastes and conservation of h2o (osmoregulation, faster/more efficient rates of feeding and food-processing. Ancestral sprawling gait of tetrapods has limitations: running interferes with costal ventilation, sprawling posture is slower/less efficient at faster gaits, sprawling posture keeps belly close to ground increased risk of injury at higher speeds. For sustained locomotion, need to keep body more rigid, rely on limbs more than trunk for locomotion. In synapsids and archosaurs, this was accomplished by bringing limbs beneath raised body. Archosaurs (dinosaurs and birds) erect posture predominates in bipedal locomotion. Some lizards use bipedal running for short bursts.
