Lecture 5 Stress Flashcards
Explain the concepts of adaptation and acclimation(phenotypic plasticity) and identify how these concepts apply to organisms dealing with heat, desiccation, and predation stress
Explain how plants and animals have different morphologies, physiologies, and behaviors to deal with the same sources of stress (functional diversity)
Understand performance curves and apply the concepts of Q10 to predict to performance
Adaptation
Evolutionary change in genotype that increases performance
Acclimation
Change in phenotype within an individual’s lifetime to increase performance (usually reversible)
Temperature applied to biochemical reactions
Rates of biochemical reactions often increase exponentially with temperature.
Temps applied with enzymes and protein
Protein and enzyme count is relatively stable as it increase temperature, but sharply declines as higher temp where they denature and lose their ability to catalyze reactions. High temps cell walls lose their integrity
What does enzymatic activity correlate with muscle performance
1:1 effect. Optimal enzymatic activity may correspond to optimal muscle performance
Ectotherms
body temperature determined primarily by external conditions
Endotherms
Body temperature determined primarily by internal, metabolic energy
What is hypothalamus purpose?
It is a major thermoregulatory integrative center of mammals.
Negative feedback loop: As temperature decreases the metabolism increases for heat production and conservation
As temp increase lower metabolic system and cool the body for heat loss
How do endotherms deal with extreme cold?
Morphology and Physiology: Low surface area to volume ratio
- Insulation
- thick plumage/fur
-thicker skin
-layer of blubber
Countercurrent exchange
Is a mechanism occurring in nature usually heat or some chemical between two flowing bodies can be liquids or any combination of those. Maximum amount of heat or mass transfer can be obtained is higher with counter current.
Example of plants doing temperature regulation (Heat Gained regulation)
(Morphology): Low growth form (decrease convection loss, Dark leaves (increase radiation gain), Hugs ground (increase conductive gain from rock
(Behavior): Orient leaves perpendicular to the sun (increase radiation gain)
Example of plants doing temperature regulation (heat loss by desert plants)
Morphology: Open growth form ( high loss to convection) , reflective leaves, reduce conductive gain
Behavior: orient leaves parallel to the sun (reduce radiation gain)
