LIFE 103 1st Edition Lecture 29 Outline of Last Lecture II Biomimicry III Form and function IV Physical constraints a Hydrodynamics II Evolutionary constraints a Vertebrate flight III Form and function IV Cursorial locomotion Outline of Current Lecture V Evolutionary constraint VI Thermoregulation VII Homeostasis VIII Generating and retaining heat IX Energy conservation Current Lecture Regulating internal environments homeostasis and thermoregulation Evolutionary constraint I II In contrast to the engineer evolution does not produce innovations from scratch It works on what already exists either transforming a system to give it a new function or combining several systems to produce a more complex one Natural selection has no analogy with any aspect of human behavior If one wanted to use a comparison however one would have to say that this process resembles not engineering but tinkering Francois Jacob Clicker question Explain the difference in ear size between African and Asian elephants in terms of functional trade offs costs benefits African elephants are often found in arid savannas Asian elephants in wet forests African elephants have larger ears to help dissipate heat in their hot habitats Body mass lifespan and metabolic rate These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute I II III IV The larger an organism the longer it takes for it to metabolically process it Two exceptions naked mole rat and bats Relationship basal metabolic rate to life span Living theory the faster you live Thermoregulation I II III IV V VI VII Biochemical reactions are temperature sensitive so small changes in temperature can have profound effects on metabolic processes Homeostasis is desirable Thermal conductivity of water and air are very different Thermal conductivity ability of a material to conduct heat Air has high thermal conductivity Water has low thermal conductivity How does this impact aquatic vs terrestrial animals Conformers stay temp as surroundings vs regulators Homeostasis I II III IV V VI How is it maintained Set point Stimulus Sensor control center Response Examples I Sweating II Behavioral regulation Thermoregulation I II III IV Endotherm generates metabolic heat I Ex mammals and birds Homeotherm relatively constant temperature Ectotherm use environmental heat I Ex insects frogs Poikilotherm variable temperature Generating and retaining heat I II III IV Some ectotherms use shivering thermogenesis to generate heat Behavioral heat absorption basking collecting heat from the environment Insulation helps retain heat in mammals and birds I Blubber fur Countercurrent heat exchange V I Keeps cold blood at the bottom and warm blood at the top II Seen with dolphins and sharks and geese Vasodilation and vasoconstriction I Changes how capillaries act to lose heat or avoid it II Vasoconstriction losing heat less rapidly III Vasodilation losing heat more rapidly Thermoregulation and energy conservation I II III IV V VI VII VIII IX X Torpor a state of decreased physiological activity Small endotherms birds and mammals that are active with high metabolic rates Daily pattern Problem how to survive unfavorable conditions Escape or endure Hibernation seasonal state of reduced physiological activity Mostly mammals Set point is greatly reduced sometimes to nearly 0 degrees C Often accompanied by periodic arousals Brumation seasonal torpor in reptiles Aestivation summer hibernation often facultative Disease I II III White nose syndrome Fungal disease that affects bats 99 9 mortality rate
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