35 lines
1.8 KiB
Markdown
35 lines
1.8 KiB
Markdown
# Endothermy
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- Present in [[Mammalia]] and [[Aves]]
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- [[Brown fat]] [[mitochondrion]]
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- Puts food and oxygen towards generating heat instead of ATP
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- Maintaining body temperature is important for [[enzymes]] to operate
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- Metabolic rate _decreases_ when temperature increases, the direct opposite
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of [[ectothermy]]
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- [[Fish]] swimming styles
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- [[Tuna]]: [[Thunniform swimming]] with a narrow [[caudal peduncle]] and a
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sickle-shaped tail, leaves less turbulence behind and uses less energy
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- [[Trout]]: [[Subcaraigiform swimming]] leaves turbulence behind but allows
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more mobility
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- Most kinds of fish are [[ectothermy|ectothermic]]
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- Thunniform swimmers have the muscles they use on their inside, so heat
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is generated internally, where most fish have their swimming muscles on
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the outside which get cooled by the water
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- This elevated body temperature allows them to be fast thinkers and movers
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- Endothermy is costly
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- We expect endotherms to reduce the costs via adaptations
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- We expect endothermy to only evolve when the costs can be offset
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- Minimizing heat loss
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- [[Gigantothermy]]: The bigger you are, the less surface area there is to
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lose body temperature to
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- Allow temperature to drop purposefully during some times in some places
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- [[Hibernation]]
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- Reducing circulation
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- [[Insulation]]: Hot-body radiation only occurs at the surface, so if
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you can prevent heat from reaching the surface, you can prevent
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hot-body radiation
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- [[Feathers]]: When you pick up a bird it will be cold, although without
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its feathers it would be warm
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- [[Countercurrent Heat Exchange]]: If the blood on the way back from
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an extremity would be cold, wrap the veins around the arteries so the
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returning blood warms up while the leaving blood cools
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