DESERT ADAPTATION CONCEPTS

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DESERT ADAPTATION CONCEPTS
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Vant Hoffs Rule for every temperature rise of
10o C, rate of biochemical reactions double up to
a point.

• This is why it is bad to get too hot or too cold
• Too cold body functions slow due to Vant
  Hoffs Rule.
• Too hot proteins break down and body functions
  slow thats why Vant Hoffs Rule only works up
  to a point.

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Energy Pie distribution of individuals energy
among

• Growth
• Reproduction
• Activity
• Maintenance includes body temp
• Storage

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How plants and animals gain and lose heat

• Radiation (/-) to/from nearby objects
• E.g., lizard gains heat from sun, or loses heat
  to surroundings in shade
• Conduction (/-) to/from touching objects
• E.g. lizard gains heat laying on warm rock or
  loses heat laying on surface of cool burrow
• Convection (/-) into wind/moving water
• E.g. body is warmed by hot wind or cooled by cold
  wind
• Metabolism () from bodys generation of heat
• Evaporation (-) from moist body surfaces

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Surface Area to Volume Ratio

• Small, thin things have a greater surface area to
  volume ratio thus gain/lose heat faster than
  large, thick things.

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Types of animals based on way body temp is
maintained

• Endotherms principal source of body heat is
  bodys metabolism (erroneously called
  warm-blooded)
• Birds Mammals
• Ectotherms principal source of body heat is from
  environment (erroneously called cold-blooded)
• Everything else (with a few exceptions)

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Types of Thermoregulation

• Physiological thermoregulation altering bodys
  metabolic generation of heat to regulate body
  temp.
• Behavioral thermoregulation altering posture,
  orientation, and/or microclimate to regulate body
  temp.

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Advantages and Disadvantages ofEndothermy versus
Ectothermy

• Endothermy
• Advantage
• Always ready to go
• Disadvantage
• Uses 10x more energy

• Ectothermy
• Advantage
• Uses 10x less energy
• Disadvantage
• Prisoner of environment (cold and slow when no
  source of heat)

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Torpor lowering of body temp below activity
temperature.

• Daily Estivation lt24 hr torpor in response to
  heat and/or dryness
• Seasonal Estivation seasonal torpor in response
  to heat and/or dryness
• Daily Torpor in Response to Cold daily torpor in
  response to cold and insufficient energy uptake.
  Note name and definition are same.
• Hibernation seasonal torpor in response to cold
  and insufficient energy uptake

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TorporAdaptive Values

• Reduces Energy Needs
• 2 ways
• Reduces Water Needs
• 3 ways

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TorporAdaptive Values

• Reduces Energy Needs
• Lowers temp gradient which is the difference in
  temp between body and environment this slows
  rate of heat loss
• Less tissue demand because lower body temp

Quick heat loss
34o
34o
Slow heat loss
99o
35o
High temp gradient
Low temp gradient
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TorporAdaptive Values

• Reduces Water Needs
• Decreases cutaneous (outer surface such as skin)
  water loss
• Less evaporation
• Decreases excretory water loss
• Less waste products produced
• Decreases respiratory water loss
• Less breathing (colder body temp slows
  metabolism) and less water lost per breath
  (colder exhaled air contains less water)