Chapter four: Coping with Variation Flashcards
Why do organisms occur where they do?
Ultimately determined by a physical environment and interactions with other species.
What is a climate envelope?
A range of conditions over which a species occurs; can predict response to climate change.
What are organisms two options for coping with environmental variation?
Tolerance and avoidance.
What is physiological ecology?
The study of interactions between organisms and their environment and how these interactions influence survival and determine geographic ranges.
How does the physical environment influence an organisms ecological success?
Through availability of energy and resources. And whether extreme conditions can exceed tolerance limits.
What other factors are related to geographic distribution?
Dispersal ability, disturbance, and competition.
Explain the range of tolerance.
The range of environmental changes within which a species is able to carry out normal activities. If the upper or lower limit exceeds the range of tolerance, efficiency is effected.
What is “stress”?
Environmental change results in decreased rates of survival, growth, or reproduction.
What is the principal of allocation?
When stressed, more energy must be devoted to basal metabolism, thus less energy is available for survival. (Energy=finite)
What is acclimization?
Adjusting to stress through behavior or physiology. (Short term).
What is adaptation?
Natural selection facilitates adaptation to environmental stress in a population (Long term).
What are ecotypes?
Populations with adaptations to unique environments.
What is survival and function strongly tied to?
Internal temperature.
What are isozymes?
Different forms of enzymes with different temperature optimum. They allow for acclimatization to changing conditions.
What is an ectotherm?
Principal source of heat comes from outside the body.
Ex: Reptiles
What is an endotherm?
Can maintain constant body temperature by heat produced inside the body.
Ex: Mammals
What is a homeotherm?
The constant body temperature comes by physiological means, like metabolism.
What is a heterotherm?
Has multiple set points of temperature.
-Regional: body temperature varies on different parts of the body.
-Temporal: body temperature varies at different times.
What are poikilotherms?
Variation in body temperature under different environmental conditions.
What must organisms do to tolerate, change, or modify temperature?
Use physiology, morphology, or behavior behaviors.
Define conduction.
The transfer of energy from warmer to cooler molecules (surface contact).
Define convection.
Heat energy is carried by moving water or air. Ex: wind or bounced surfaces.
Define radiation.
Energy from the sun.
Define latent heat transfer.
Water absorbs heat as it changes from a liquid to a gas.
What are the 3 ways ectotherms gain heat?
Radiation, convection, and conduction.
What are 3 ways ectotherms lose heat?
Convection, respiration, and conduction.
What are the energy inputs for terrestrial plants?
Sunlight, infrared radiation from surrounding objects, conduction, and convection if the ground or air is warmer than the plant.
What are the energy outputs for terrestrial plants?
Emission of infrared radiation, conduction, convection, and evapotanspiration.
What controls transpiration in plants?
Stomata, tiny and specialized leaf openings.
If soil water is limited, what are the ways plants can conserve energy/water.
By shedding leaves and pubescence (hairs on a leaf that reflect solar energy)
Define the thermal neutral zone.
Endotherms maintain constant basal metabolism over a range of environmental temperatures.
Define basal metabolic rate.
The amount of oxygen consumed per time unit at a standard temperature.
And the amount of energy spent at rest.
Define relative or mass-specific metabolic rate.
Meaning metabolic rate is adjusted for body size.
As body size increases, relative BMR decreases.
(Large endotherms lose energy/heat more slowly.)
Name the behavioral adjustments for a lower critical temperature.
Huddling, piloerection (hair stands up), elaborate nests, restricting foraging areas, food hoarding, and restricting level of activity.
Name the morphological adjustments for a lower critical temperature.
Bergman’s rule (body size increases with latitude.)
Allen’s rule (colder climates results in shorter appendages.)
Gloger’s rule (drier climates results in lighter pigment)
Name the physiological adjustments for a lower critical temperature.
Insulation with fur/feathers.
Countercurrent heat exchange (changes in blood flow to peripheral tissues)
Dormancy (torpor, hibernation, and winter lethargy)
Thermogenesis (Shivering v.s. nonshivering)
Name the behavioral adjustments to a upper critical temperature.
Burrowing, denning, fanning.
Shading with appendages
Diet, including more water.
Restrict level of activity.
Name the morphological adjustments to a upper critical temperature.
Decreased body size (Bergman’s rule)
Longer appendages (Allen’s rule)
Darker skin pigment (Gloger’s rule)
Name the physiological adjustments to a upper critical temperature.
Evaporative cooling (sweating, panting, salvia spreading, respiratory heat exchange.)
Dormancy
