Ecology Test 2 (Physiological Ecology 1)

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What 2 things are organisms adapted to?
* a limited rage of environmental conditions * to compensate for a certain range of variation i environmental conditions
So what are organisms shaped by?
selection under the conditions that they encounter regularly
For an example, what does temperance tolerance look like?
always closed bell curve; vary in peak and width - closed to tolerance and performance functionsex: different photosynthetic pigments; specialize on different wavelengths
What is the difference between caratenoids and chlorophylls?
carotenoids: peak at about 500 nm (blue, green); reflect yellow and orange (trees in fall)
chlorophylls: peak at about 700 nm (orange red); reflect blue and green
What happens to most of the UV and shorter rays?
get filtered out by the atmosphere (re. ozone depletion)
IR: heat
At what wavelengths does photosynthetically active radiation occur? 
400-700 nm
What happens to wavelengths in water?
* differential absorption and scatter of wavelengths
* energy visible spectrum is reduced: by 50% at 10 m, by 93% at 100 m; longer waves absorbed more, shorter waves scatter
What color light dominates with increasing depth?
Specialization according to water depth: what light do orgs use?
shallow: spp that use chlorophylls (use red light) ex: green algae
deep: spp thatt use carotinoids (use blue-green light)
What do levels of tolerance look like for survival, growth and reproduction? (graph)
What does this mean?
bell curve: survival (bottom-widest range), growth (middle, more narrow range), reproduction (narrowest-top of curve)
* successful reproduction/population maintenance is at narrower ranges
What else does this graph show?
environmental variation: different consequences for different processes
Example of how tolerance functions vary in width.
homeotherms (birds and mammals): maintain nearly constant body temperature
* thermal neutral zone (TNZ): range of temps at which temp regulation can be accomplished with resting metabolic rate
What happens when an organism is outside the TNZ?
What is a downside?
temperature regulation requires INCREASE in resting metabolic rate (can reach 2-3 times resting rate)
How do tropical spp and arctic spp differ in variation of TNZ?
tropical spp: maintain constant metabolic rate over a NARROW range of temps (monkeys, humans, sloths)
arctic spp: maintain constant metabolic rate over a BROAD range of temps (polar bear, arctic fox)
* arctic spp would survive better in climate change circumstance
What does this tell us about organisms?
orgs shaped by selection under conditions they regularly encounter
What are the orgs called that DO NOT regulate body temp?
What are the orgs that DO regulate body temp?
What are the differences btw them?
Ectotherm: use environment or behavior (heat from outside)
Endotherm: internal metabolism (heat from inside)
Homeotherms: internal metabolism and about constant temperature
Example of an endotherm?
Skunk cabbage: early bloomers; generate heat to melt snow if necessary and monopolize other plants; metabolize much when cold and vise-versa
How do orgs use countercurrent heat exchange to stay warm?
birds: minimize heat loss from legs/feet (warm blood coming down heats cooler blood moving up)
dolphins and blue fin tuna (ectotherm): use same technique in fins/flippers
How do orgs deal with high temps?
reduce sun exposure/increase cooling
What does convergence in adaptations help us understand?
adaptation and selection
convergence: how do cicadas stay cool?
thermoregulation by evaporation (like humans)
Why can very low temps to damaging to orgs?
ice crystals damage cell structure when cells freeze
How to orgs maintain body temp above freezing?
use metabolism to generate heat (endo- and homeotherms); insulation, fur, blubber
How do orgs resist freezing?
antifreeze-like compounds: glycerol, glycoproteins - lower freezing point (antarctic fish)

supercooling body fluids: glycoproteins coat developing ice crystals that could act as "seeds"; water can cool 20 C below freezing point without freezing (reptiles, invertebrates)
How to orgs tolerate freezing?
surviving with 50% or more of total body water frozen
Aquatic orgs regulating water and ion concentration:
what is iso-osmotic?
concentration of water and ions same in water and org
What is hypo-osmotic?
higher water and lower ions in org (marine)
What is hyper-osmotic?
lower water and higher ions in org (freshwater)
Why is this regulation a challenge for fish?
they need to breathe with their gills, but this exposes them more to the water
How do marine (hypo-osmotic) fish deal with this?
* water diffuses out; replaced by drinking seawater
* ions + seawater diffuse in; eliminated through glands and concentrated urine
How do freshwater (hyper-osmotic) fish deal with this?
* water diffuses in; excreted in dilute urine
* ions diffuse out; replace through glands and food
How do cartilaginous fish (sharks) reduce osmotic gradient?
* increase osmotic potential of body fluids; retain urea in blood and Na+ and Cl- concentration stable
- weakly hyper-osmotic (overall)
- water diffuses in through gills; still gain Na+ and Cl-, but more slowly
- excrete excess water and ions in diluted urine