Corollaries: &quot;a master of one is a master of no others&quot;, &quot;adaptation comes at a cost&quot;, &quot;there&#146;s no free lunch&quot; Adaptations occur at multiple levels of organization&#151;e.g., biochemistry, tissue anatomy, whole-organism behavior We&#146;ll illustrate these points with one topic: how organisms are adapted to hot, dry climates (many of the basic principles are quite general&#151;e.g., flux laws) Plant adaptations to hot, dry environments Water loss is continual problem: Water is lost whenever leaves respire, because water gradient is steeper from inside leaf to outside than CO 2 gradient is from outside leaf to inside&#133;recall CO 2 concentration in atmosphere is only 0.03% Hot, dry climates exacerbate water loss: metabolic rates increase, water vapor gradient from cells to atmosphere increases transpiration, soils become dry via evaporation Variety of adaptations Increase osmotic potential of roots to pull water from soil by increasing solutes in cell solutions&#151;e.g., desert plants can increase water potential of roots up to 60 bars (recall 15 as typical value).
(organisms; are adapted; to hot, dry climates) (water gradient; is; steeper from inside leaf to outside) (leaves; respire; ) (2 concentration in atmosphere; is; only 0.03% Hot, dry climates exacerbate water loss: metabolic rates increase, water vapor gradient from cells to atmosphere increases transpiration, soils become dry via evaporation Variety of adaptations Increase osmotic potential of roots to pull water from soil by increasing solutes in cell solutions&#151;e.g., desert plants can increase water potential of roots up to 60 bars) (Water loss; is; continual problem: Water is lost whenever leaves respire, because water gradient is steeper from inside leaf to outside than CO 2 gradient is from outside leaf to inside&#133;recall CO 2 concentration in atmosphere is only 0.03% Hot, dry climates exacerbate water loss: metabolic rates increase, water vapor gradient from cells to atmosphere increases transpiration, soils become dry via evaporation Variety of adaptations Increase osmotic potential of roots to pull water from soil by increasing solutes in cell solutions&#151;e.g., desert plants can increase water potential of roots up to 60 bars) (Variety of adaptations; Increase; osmotic potential of roots to pull water from soil by increasing solutes in cell solutions&#151) (CO 2 gradient; is; from outside leaf to inside&#133) (Water; is lost; ) (soils; become; dry) (a master; is a master of; one) (one; is a master of; no others & quot)
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to hot, dry climates
steeper from inside leaf to outside
only 0.03% Hot, dry climates exacerbate water loss: metabolic rates increase, water vapor gradient from cells to atmosphere increases transpiration, soils become dry via evaporation Variety of adaptations Increase osmotic potential of roots to pull water from soil by increasing solutes in cell solutions&#151;e.g., desert plants can increase water potential of roots up to 60 bars
continual problem: Water is lost whenever leaves respire, because water gradient is steeper from inside leaf to outside than CO 2 gradient is from outside leaf to inside&#133;recall CO 2 concentration in atmosphere is only 0.03% Hot, dry climates exacerbate water loss: metabolic rates increase, water vapor gradient from cells to atmosphere increases transpiration, soils become dry via evaporation Variety of adaptations Increase osmotic potential of roots to pull water from soil by increasing solutes in cell solutions&#151;e.g., desert plants can increase water potential of roots up to 60 bars
osmotic potential of roots to pull water from soil by increasing solutes in cell solutions&#151
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