Temperature Relations

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Temperature Relations

• Chapter 4

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1. Define terms associated with Microclimates

• Macroclimate Large scale weather variation.
• Microclimate Small scale weather variation,
  usually measured over shorter time period.
• Variation in temp, light esp.
• Altitude
• Higher altitude - lower temperature.
• Aspect
• Offers contrasting environments.
• Vegetation
• Ecologically important microclimates.

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2. Describe some examples of Microclimates.

• Ground Color
• Darker colors absorb more visible light.
• Boulders / Burrows
• Create shaded, cooler environments.

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3. Why are Aquatic Temperatures more stable than
terrestrial?

• Specific Heat
• Absorbs heat without changing temperature.
• 1 cal energy to heat 1 cm3 of water 1o C.
• Air - .0003 cal
• Latent Heat of Evaporation
• 1 cal can cool 580 g of water.
• Latent Heat of Fusion
• 1 g of water gives off 80 cal as it freezes.
• Riparian Areas

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4. How does riparian vegetation influence
Aquatic Temperatures? Why is this relevant in
Illinois?

• Riparian vegetation influences stream temperature
  by providing shade.

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5. How does temperature work at the biomolecular
level?

• Biomolecular Level
• Most enzymes have rigid, predictable shape at low
  temperatures
• Low temperatures cause low reaction rates, while
  excessively high temperatures destroy the shape.
• Baldwin and Hochachka studied the influence of
  temperature on performance of acetylcholinesterase
  in rainbow trout (Oncorhynchus mykiss).

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AcH Rainbow Trout

• 2 forms
• 1 optimum 0- 4 C
• 1 optimum about 20 C
• Neither temp optimum for warm water

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5. Temp function on Biomolecular level - Limits
of enzyme systems

• Temperature optimum 50- 80 for most life
• Exceptions?
• Ph optimum for most life 6-8
• Human/ animal systems?
• Any exceptions?
• Enzyme concentration
• Presence of anti-freeze substances
• Caribou
• Artic hare

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6. How do Extreme Temperatures affect
Photosynthesis?

• Photosynthesis equation what part influenced by
  temp?
• 6CO2 12H2O ? C6H12O6 6O2 6H20
• Extreme temperatures usually reduce rate of
  photosynthesis.
• Different plants have different optimal
  temperatures.
• Acclimation Physiological changes in response to
  temperature.

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Optimal Photosynthetic Temperatures
After adapting to environment
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7. How does Temperature affect Microbial
Activity?

• Morita studied the effect of temperature on
  population growth among psychrophilic marine
  bacteria around Antarctica.
• Grew fastest at 4o C.
• Some growth recorded in temperatures as cold as -
  5.5o C.
• Some thermophilic microbes have been found to
  grow best in temperatures as hot as 110o C.
• http//www.metric-conversions.org/temperature/cels
  ius-to-fahrenheit.htm

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8. How does Optimal Growth temperature vary in
bacteria? Examples
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9. Balancing Heat Gain Against Heat Loss

• HS Hm Hcd Hcv Hr - He
• HS Total heat stored in an organism
• Hm Gained via metabolism
• Hcd Gained / lost via conduction
• Hcv Gained / lost via convection
• Hr Gained / lost via electromag. radiation
• He Lost via evaporation

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Mechicanisms of heat loss/ gain

• Metabolism internal chemical changes
• Conduction
• Heat conduction -- the conduction of heat through
  matter
• Electrical conduction -- the conduction of
  charged particles through matter
• Nerve conduction -- the conduction of signals
  along nerve cells
• Convection - wind
• Radiation suns warmth or heat generated by
  plant or animal
• Evaporation heat loss w/ water loss

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Heat Exchange Pathways
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10. Temperature Regulation by Plants

• Desert Plants Must reduce heat storage.
• Hs Hcd Hcv Hr
• To avoid heating, plants have (3) options
• Decrease heating via conduction (Hcd).
• Shade at ground surface
• Increase convective cooling (Hcv).
• Needle like leaves allow wind through
• Reduce radiative heating (Hr).
• Reduce leaf surface
• Orient to sun

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Temperature Regulation by Plants
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Temperature Regulation by Plants

• Arctic and Alpine Plants
• Two main options to stay warm
• Increase radiative heating (Hr).
• Decrease Convective Cooling (Hcv).
• Tropic Alpine Plants
• Rosette plants generally retain dead leaves,
  which insulate and protect the stem from
  freezing.
• Thick pubescence increases leaf temperature.

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Temperature Regulation by Thermogenic Plants

• Almost all plants are poikilothermic ectotherms.
• Plants in family Araceae use metabolic energy to
  heat flowers.
• Skunk Cabbage (Symplocarpus foetidus) stores
  large quantities of starch in large root, and
  then translocate it to the inflorescence where it
  is metabolized thus generating heat.

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Eastern Skunk Cabbage
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11. Variation in Body Temperature Regulation
with animal type

• Poikilotherms
• Body temperature varies directly with
  environmental temperature.
• Ectotherms
• Rely mainly on external energy sources.
• Endotherms
• Rely heavily on metabolic energy.
• Homeotherms maintain a relatively constant
  internal environment.

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11. Temperature Regulation by Ectothermic Animals

• Liolaemus Lizards
• Thrive in cold environments.
• Burrows
• Dark pigmentation
• Sun Basking
• Grasshoppers
• Some species can adjust for radiative heating by
  varying intensity of pigmentation during
  development.

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Surviving Extreme Temperatures

• Inactivity
• Seek shelter during extreme periods.
• Reducing Metabolic Rate
• Hummingbirds enter a state of torpor when food is
  scarce and night temps are extreme.
• Hibernation - Winter
• Estivation - Summer

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11. Temperature Regulation by Endothermic Animals

• Thermal neutral zone is the range of
  environmental temperatures over which the
  metabolic rate of a homeothermic animal does not
  change.
• Breadth varies among endothermic species.

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12. Thermal Neutral Zones
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13. Swimming Muscles of Large Marine Fish

• Lateral swimming muscles of many fish (Mackerel,
  Sharks, Tuna) are well supplied with blood
  vessels that function as countercurrent
  heat-exchangers.
• Keep body temperature above that of surrounding
  water.

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13. Countercurrent Heat Exchange
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13. Countercurrent Heat Exchange ex 2
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14. Temperature Regulation by Endothermic Animals

• Warming Insect Flight Muscles
• Bumblebees maintain temperature of thorax between
  30o and 37o C regardless of air temperature.
• Sphinx moths (Manduca sexta) increase thoracic
  temperature due to flight activity.
• Thermoregulates by transferring heat from the
  thorax to the abdomen

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14. Moth Circulation and Thermoregulation
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15. Plant types adapted to temperature.

• Geophyte underground bulb
• Cryptophyte - hidden plant perennial die back
  to roots
• Hemicryptophyte ½ hidden - vines
• Phaenerophyte - seeds

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