BIOL 111 Lecture 22: Birds

• School: McGill University
• Department: Biology
• Course: BIOL 111
• Professor: Andrew Hendry

Document Summary

Introduction: around 9600 species, amniotes, 4-chambered heart (completely separate pulmonary and systemic circuits, mostly fly, bird beaks ----- evolve from different function of diverse diets, woodpecker: chiseling function. Skimmer: lower beak is longer than my upper beak so that it can skim the water and catch fish while flying: crossbill: found in north america ---- coniferous-seed eating. Generate their own internal heat through metabolic processes. Eg. many fish are homeotherms and not endotherms: mechanisms to maintain body temperature, behavioral thermoregulation, orientation relative to heat source, basking (marine iguana), huddling (penguin) and varying contact with heat surface, moving location throughout the day. A lizard maintains its body temperature between upper and lower limits by moving between hot and cold microhabitats: physiological, too hot: increase blood flow to periphery, sweating, panting, too cold: decrease blood flow to periphery, shiver, eg. Human thermostat ---- in hypothalamus and negative feedback system. If temperature is too high: sweat ---- evaporative cooling.