Thermoregulation

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Thermoregulation
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Thermoregulation

• Homeothermy (endothermy)

• Cellular
• Behavioral
• Morphological
• Environmental

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HS HR HE HK HC HM
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HS HR HE HK HC HM
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HS HR HE HK HC HM
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HS HR HE HK HC HM
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HS HR HE HK HC HM
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HS HR HE HK HC HM
-HK (Tb Ta) / I
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HS HR HE HK HC HM
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HS HR HE HK HC HM
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Thermoregulatory Adaptations
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Countercurrent Exchange

• Minimize heat lost from extremities
• Can be bypassed
• Tuck in apteria if too cold

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Thermoneutral Zone

• Within this zone, thermoregulation without extra
  energy expenditure

TNZ
Metabolic Rate
Body Temp
BMR
LCT
UCT
Ta
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Hyperthermia
-HK (Tb Ta) / I

• During Flight
• Increased temperatures difficult
• Increased water consumption difficult

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Hypothermia
-HK (Tb Ta) / I

• Large birds have lower LCT
• Large birds better at shivering
• Smaller birds lower body temp (5-10F)

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Torpor

• Nightly
• Todies
• Hummingbirds
• Days to Weeks
• Poorwills
• Size vs. Time
• Heat loss / Reheat
• Energy to reanimate
• Vulnerability