Individual Ecology

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Individual Ecology

• Relationship of individual with its environment
• Strong impact on distribution and abundance of
  organisms

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Physiological Ecology

• Ecology - concerned with distribution of
  organisms
• Physiology - concerned with function of organisms
• Combined how function of organisms affects their
  distribution

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Microhabitat

• Important factors
• Altitude
• Aspect
• Vegetation life
• form
• Ground Color
• Objects in the
• environment (e.g.,
• boulder, burrows)

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Microhabitats
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Thermal Microclimates
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Temperature Relations

• Most species perform best in narrow range of
  temps
• Enzymes have optimal temperatures
• Temperature extremes impair enzyme functioning

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Enzymatic Variation

• Range of conditions individual can function in
• Range more narrow than environmental variation
• Individual needs to regulate body temp to stay in
  the acceptable range
• Acclimation (physiological not genetic changes)

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Enzyme Activity in Trout

• Two forms of acetylcholinesterase
• Rainbow trout native to cool streams
• Winter temps 0-4C
• Summer temps 20

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Heat Transfer

• Conduction - heat transfer between bodies in
  direct physical contact
• Convection - Transfer of heat between a solid and
  a moving fluid (air or water)
• Radiation - transfer of heat between objects
  without contact
• Evaporation - heat lost as water evaporates

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Heat Transfer

• Conduction
• Convection
• Radiation
• Evaporation

• Conduction
• Convection
• Radiation

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How Do Individuals Regulate Temperature?


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Endothermy vs. Ectothermy
Endotherms
generate their own heat
rely on environmental sources
Ectotherms
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Some (more) Thermal Jargon
Homeotherms
maintain a constant Tb
Poikilotherms
Tb varies with environmental T
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Temperature Regulation in Plants

• Almost all are ectotherms
• Have many adaptations for reducing and increasing
  heat storage

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Reducing Heat
x
Heat Stored Heat produced Heat In - Heat Out

• Options?
• ? radiation in, conduction in
• ? convection away
• ? evaporation?
• No, conserve water

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Decrease Radiation Gain

• Reflective surface
• White plant-hairs
• Orient parallel to sunlight

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Reduce heat gain

• ? conductive gain
• Limit contact with ground
• ? convection away
• ? surface area for wind

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Desert Plants
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Increasing heat storage- plants
x
Heat Stored Heat produced Heat In - Heat Out

• Options
• ? radiation in, conduction in
• ?convective cooling
• ? evaporative cooling

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Increase Heat

• Dark pigments
• Orient leaves perpendicular to sunlight
• Grow close to ground
• ? radiation and conduction
• ? convective cooling

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Skunk Cabbage
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Thermoregulation in Ectothermic Animals

• Alter gain from radiation
• Seek sun and shade
• Pigmentation change
• Alter conduction
• Lay flat / Push away
• Alter convective cooling

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Alter Evaporative Cooling
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Temperature Regulation in Endotherms


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Endotherms

• Still do behavioral regulations
• Internal heat production becomes most important

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Thermal Neutral Zone

• Range of environmental temps at which metabolic
  rate doesnt change
• Colder - ? MR
• shiver
• Warmer - ? MR
• ? heart rate and blood flow to skin

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High temps - High Blood Flow
? Evaporative cooling
? Convective cooling
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Thermal neutral zone
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Allens rule

• Endothermic species from colder climates will
  have shorter appendages, ears, etc

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Bergmans Rule

• Endothermic individuals will be bigger in colder
  climates
• Decrease SAV

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Heterotherms

• Some endotherms do not always maintain a constant
  Tb
• Torpor
• Hibernation
• Estivation

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Torpor
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Marine Mammal Thermoregulation
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Desert Gazelle
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Major Conclusion

• Temperature is VERY important factor in
  determining the distribution of organisms
• Kelp
• Coral 20 0C
• No moose in Florida
• No lizards in Maine