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Temperature Relations
Chapter 5
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Co 5
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Outline
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Microclimates
Aquatic Temperatures
Temperature and Animal Performance
Extreme Temperature and Photosynthesis
Temperature and Microbial Activity
Balancing Heat Gain Against Heat Loss
Body Temperature Regulation
 Plants
 Ectothermic Animals
 Endothermic Animals
Surviving Extreme Temperatures
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Figure 05_01
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Microclimates
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Macroclimate (大氣候): Large scale weather
variation.
Microclimate (微氣候): climatic variation on a scale
of few kilometers, meters, or even centimeters,
usually measured over short periods of time.
 Altitude
 Higher altitude - lower temperature.
 Aspect
 Offers contrasting environments.
 Vegetation
 Ecologically important microclimates.
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Microclimates
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Ground Color
 Darker colors absorb more visible light.
Boulders / Burrows
 Create shaded, cooler environments.
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Figure 05_06
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Aquatic Temperatures
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Specific Heat
 Absorbs heat without changing temperature.
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o
 1 cal energy to heat 1 cm of water 1 C.
 Air - .0003 cal
Latent Heat of Evaporation
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 About 584 cal per gram of water at 22 C
and 580 cal per gram of water at 35 oC.
Latent Heat of Fusion
 1 g of water gives off 80 cal as it freezes.
Riparian Areas
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Aquatic Temperatures
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Riparian vegetation influences stream
temperature by providing shade.
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5.2 Evolutionary Trade-offs
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Organisms allocate limited energy to a
certain function which then reduces the
amount for other functions.
 This trade-off (交換) in energy allocation
(配置) will differ among environments
with functions that include growth,
reproduction, and defense against
predators
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The Principle of Allocation
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Levins concluded that the evolutionary
consequences of this trade-off results in
populations having high fitness (適當) in one
environment, but lowered fitness in another
environment.
Bennett and Lenski found support for Levins’
Principle of Allocation using experiments
with Escherichia coli grown in different
temperature environments.
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The Principle of Allocation
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Temperature and Animal Performance
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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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Figure 05_10
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Extreme Temperatures and Photosynthesis
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Photosynthesis
6CO2 + 12H2O  C6H12O6 + 6CO2 + 6H20
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Extreme temperatures usually reduce rate
of photosynthesis.
 Different plants have different optimal
temperatures.
 Acclimation (馴化): Physiological
changes in response to temperature.
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Figure 05_11
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Optimal Photosynthetic Temperatures
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Temperature and Microbial Activity
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Morita studied the effect of temperature on
population growth among psychrophilic (嗜冷
性的) marine bacteria around Antarctica.
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 Grew fastest at 4 C.
 Some growth recorded in temperatures as
cold as - 5.5o C.
Some thermophilic （嗜熱性的）microbes
have been found to grow best in
temperatures as hot as 110o C.
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Optimal Growth Temperatures
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Optimal Growth Temperatures
Antarctic bacteria
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Optimal Growth Temperatures
Hot spring microbes
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Balancing Heat Gain Against Heat Loss
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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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Heat Exchange Pathways
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Body Temperature Regulation
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Poikilotherms (變溫動物)
 Body temperature varies directly with
environmental temperature.
Ectotherms (外溫動物)
 Rely mainly on external energy sources.
Endotherms (內溫動物)
 Rely heavily on metabolic energy.
 Homeotherms (恒溫動物) maintain a
relatively constant internal environment.
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Temperature Regulation by Plants
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Desert Plants: Must reduce heat storage.
 Hs = Hcd  Hcv  Hr
 To avoid heating, plants have (3) options:
 Decrease heating via conduction (Hcd).
 Increase conductive cooling (Hcv).
 Reduce radiative heating (Hr).
Leaves with a dense coating of white
plant hairs.
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Temperature Regulation by Plants
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北極與高山植物的平鋪生長植物
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Temperature Regulation by Plants
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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. (蓮座型植物)
 Thick pubescence increases leaf
temperature. (軟毛)
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A cushion plant
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柳樹
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Temperature Regulation by Ectothermic Animals
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Eastern Fence Lizard (Sceloporus undulatus)
東方強稜蜥
 Metabolizable energy intake maximized at
33ºC
 Preferred temperature closely matches the
temperature at which metabolizable
energy intake is maximized
Grasshoppers (透翅蝗)
 Some species can adjust for radiative
heating by varying intensity of
pigmentation during development.
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Figure 05_20
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撫養
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高溫抑制食蟲菌
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Temperature Regulation by Endothermic Animals
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Thermal neutral zone (熱中性區) 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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Thermal Neutral Zones
樹懶
絨猴
松鼠
幼仔
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Temperature Regulation by Endothermic Animals
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Swimming Muscles of Large Marine Fish
 Lateral swimming muscles of many fish
(Mackerel Sharks 灰鯖鯊, Tuna 鮪魚) are
well supplied with blood vessels that
function as countercurrent heatexchangers.
Keep body temperature above that of
surrounding water.
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Countercurrent Heat Exchange
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Countercurrent Heat Exchange
藍鰭鮪魚
皮膚的
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Temperature Regulation by Endothermic Animals
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Warming Insect Flight Muscles
 Bumblebees (雄蜂) maintain temperature
of thorax (胸甲) between 30o and 37o C
regardless of air temperature.
 Sphinx moths 天蛾科 (Manduca sexta)
increase thoracic temperature due to flight
activity.
 Thermoregulates by transferring heat
from the thorax to the abdomen
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Moth Circulation and Thermoregulation
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Temperature Regulation by Thermogenic Plants
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Almost all plants are poikilothermic (變溫的)
ectotherms (外溫生物). Plants in family
Araceae use metabolic energy to heat
flowers (天南星科).
 Skunk Cabbage (Symplocarpus foetidus
臭菘) stores large quantities of starch in
large root, and then translocate it to the
inflorescence (花序) where it is
metabolized thus generating heat.
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Eastern Skunk Cabbage (臭菘)
肉
穗
花
序
主根
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虎甲蟲
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棲息
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Surviving Extreme Temperatures
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Inactivity
 Seek shelter during extreme periods.
Reducing Metabolic Rate
 Hummingbirds enter a state of torpor (蟄
伏) when food is scarce and night temps
are extreme.
 Hibernation (冬眠) - Winter
 Estivation (夏眠) - Summer
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