Transcript Macro-climate

Macro-climate
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Radiation, wind, precipitation, Coriolis
force
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Effects of latitude, land & water,
maritime climate, topography, etc.
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Rainshadow effect
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Major biome: desert, grassland, forest,
taiga, tundra
What aspect of environmental
factors is relevant?
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Maximum, minimum, averages, or the
level of variability? synergistic effect?
Micro-climate
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thermal profile
Aquatic ecosystem
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light, thermocline, salinity, etc.
Physical resources and limiting
factors
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Range of the optimum
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Liebig's law of minimum
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Shelford's law of tolerance
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Limiting factors
Effects of abiotic factors on
distribution and abundance
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Temperature - treeline and coral
bleaching
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Water and salinity - fog belt and tidal
flooding
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Nutrient - lemming cycle
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Phenotypic plasticity-- environmentally
induced phenotypic variation
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Acclimation (vs. acclimatization) -physiological adjustment to a changed
environment
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Principle of allocation: trade-offs in
allocating time, energy, and other
resources among various conflicting
demands
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Homeostasis--Maintenance of relative
constant internal conditions in the face of
a varying external environment
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Adaptation to heat, cold, dry, wet,
pressure, low oxygen supply, etc.
Principle of heat transfer
Hs =Hm ± Hcd ± Hcv ± Hr ± He
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Hs = heat storage by the organism
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Hm = metabolic heat production (always +
for a living organism)
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Hcd, cv = conductive (and convective) heat
exchange
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Hr = radiation heat exchange
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He = evaporate heat exchange
Temperature regulation in plants
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Desert plant – ↓ heating by conduction,
↓ rates of radiative heating, ↑rates of
convective cooling
Hs =Hcd ± Hcv ± Hr
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Foliage far enough above the ground,
small leaves, open growth form,
reflective surface or dense hair,
changing orientation of leaves and stems
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Arctic and alpine plant – ↑ rates of
radiative heating, ↓ rates of convective
cooling
Hs = Hcd ± Hcv ± Hr
Dark pigment, cushion growth form,
hug the ground, change orientation
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Tropical alpine plant – little annual but
much daily temperature fluctuation
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Giant rosette growth form
retain dead leaves
dense and thick pubescence
retaining large amount of water to
store heat
close over the apical buds at night
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ectotherm vs. endotherm
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poikilotherm vs. homeotherm
E = cm0.67
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Body mass ~ metabolic rate ~ food
habits ~ foraging behavior ~ home range
~ social organization
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morphological, physiological,
behavioral specialization
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Morphological
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Behavioral
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Bergman's rule, Allen's rule,
pigmentation, fur, blubber, …
Basking, hiding, shivering, huddle, …
Physiological
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Hypo-, hyper-thermia, countercurrent
heat exchange, torpor…
Other factors
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Moisture, nutrient, light, pH, soil, etc.
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Tolerance of pollution
Fire
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Types of fire: surface, ground, crown
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Effect of fire
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removal of plant cover
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removal of litter
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effects on minerals
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effects on animals
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Effect of typhoon
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Responses to climatic changes
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Ecological indicators
Distribution of snail and
ground temperature
Herbivory and plant defenses
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morphological defenses
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chemical defenses
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associational resistance
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enemies hypothesis
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resource concentration
hypothesis
Effects of herbivory
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Individual, population, communities,
types of animals, productivity
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Direct effect: survival, fecundity, and
growth
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Indirect effect: changes in competition
between species and microclimate
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At ecosystem level
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Structure and plant composition
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Redistribution of nutrient through
droppings
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erosion
Antipredator
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Individual strategies
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Hiding
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Making prey location more difficult, e.g.
freezing, camouflage, mimicry (Batesian
vs. Mullerian), removing evidence
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Making predator hesitate
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Making capture more difficult, e.g.
vigilance, stotting, fleeing, misdirecting
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Fight back: physical resistance or
chemical warfare
Cooperative defense
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increase vigilance
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selfish herd
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dilution effect
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group mobbing
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Alarm call
Optimal theory
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The theory used to generate hypotheses
about the adaptive value of characteristics
which analyzes the costs and benefits of
alternative decisions in terms of their fitness
payoffs
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Behavioral strategies be analyzed in terms of
cost and benefit in affecting Darwinian
fitness (survival and reproduction)
Selecting what to eat (optimal diet)
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Profitability of prey = E/h
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When encounter prey 1, eat prey 1.
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When encounter prey 2, eat prey 2
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if gain from eating prey 2 > gain from rejecting
prey 2 and searching for another prey 1
E1/ h1 > E2/ h2, eat E2
if E2 / h2 > E1/(S1 + h1) or S1> (E1h2 / E2) - h1
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Prediction
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Predator should be either a specialist or
generalist.
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The decision of specializing depends on S1 (or
the availability of prey 1)
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The switch should be sudden
Examples: bluegill sunfish, great tit, crows,
oystercatchers, etc.