Development of endothermy in birds: patterns and mechanisms.

摘要: Endothermy is a conspicuous and important adaptation in birds. Even though juvenile adult birds are endothermic maintain constant, high body temperature by means of internal heat production, they begin life expressing an ectothermic phenotype. Depending on where species falls along continuum maturity at hatching, from precocial to altricial, express traits either close the time hatching or as nestlings over period 1-3 weeks. Developing endothermy requires attaining basal metabolic rate associated aerobic scope produce sufficient heat, insulation retain internally produced thermostat that "turns on" production response cooling ambient temperatures. To support costs endothermy, animal must have capacity deliver oxygen nutrients heat-generating tissues. In this review, we examine development physiological morphological required for discuss their potential limit endothermy. These include ventilatory cardiovascular function, contribution visceral organ masses, membrane lipid composition, substrate supply pathways, skeletal muscle physiology. The developmental trajectories each these systems altricial can significant effects