Dinosaur thermoregulation

Dinosaur thermoregulation - Dinosaur thermoregulation...

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Dinosaur thermoregulation chapter 15
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At least since the 1970’s, paleontologists have debated whether or not dinosaurs were “warm” or “cold-blooded” The real issue that paleontologists are trying to resolve is where dinosaurs derived their body heat from; which has implications on whether they were active animals, like today’s birds and mammals, or whether they were sluggish, like reptiles and amphibians
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A problem arises when we apply value judgments to the issue; that is, we associate “warm-blooded” with advanced & good, and “cold-blooded” with primitive & bad
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Problems with terminology “warm-blooded” and “cold-blooded” are not good terms to use for multiple reasons: They have value judgments associated with them Animals that we think of as “cold-blooded” can have elevated body temperatures when they have basked in the sun for a long time or when they engage in certain activities The key to resolving the terminological issue is in how the animal’s body heat is generated- from within, or from without
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New terminology To avoid value judgments and other problems, we will use the following terms: Ectotherm - an animal that regulates its body temperature using an external heat source (e.g., the sun) Endotherm - an animal that regulates its body temperature using internal heat derived from its metabolism
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Additional terminology Poikilotherms have fluctuating temperatures, and both ectotherms and endotherms can be poikilotherms Lizards are ectothermic poikilotherms Bats are endothermic poikilotherms Homeotherms have constant body temperatures Humans are endothermic homeotherms
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Is the previous value judgment justified? Endothermy is very energetically costly, so
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This note was uploaded on 04/22/2008 for the course GEOL 111 taught by Professor Getty during the Fall '07 term at UConn.

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Dinosaur thermoregulation - Dinosaur thermoregulation...

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