Chapter 3: Environmental Conditions Flashcards
How do environmental conditions differ from environmental resources?
Environmental conditions are not consumed, used up or made more or less available to others like environmental resources.
Define Homeotherm
organisms that maintain a constant body temperature
Define Poikilotherm
Organisms that have body temperatures that vary passively with ambient temperature
Define Ectotherm
Organisms that use external heat sources to regulate body temperature
Define Endotherm
Organisms that use internally produced heat to regulate body temperature
List the factors that influence the amount of solar radiation absorbed by an animal.
time of day, amount of dust in the atmosphere, clouds and color of an organism
Under what conditions does thermal radiation flow into an animal’s body?
if the surroundings are warmer than the organism
Define convection and comment on its importance for heat exchange in animals.
Convection is the heat transfer from an object to a fluid that surrounds it. This is important because animals can spread out or curl up depending on what they want their temperature to be.
What parameters determine the direction and effectiveness of convectional heat exchange between an animal and its surroundings?
Temperature of the animal and its surroundings, the shape of the animal and the wind speed
How might an animal modify the amount of heat lost or gained by convection?
by changing its body shape by spreading out or curling up in a ball
What is conduction and how might an animal exchange heat by conduction?
Conduction is heat exchange through physical contact between the animal and its substrate ie; by pressing its body to a warm surface
How do animals lose heat by evaporation?
they coll by water loss from their respiratory tract or sweat glands
What is required for an animal to use metabolic heat for thermoregulation?
some form of insulation ie; hair, feathers, scales
What kind of fixed properties might influence the amount of heat gained by solar radiation?
reflective or shiny leaves in desert plants, wing pigmentation in alpine butterflies
What kind of behavioral and physiological responses might an ectotherm use to regulate body temperature?
Behavioral: parallel or perpendicular basking, shuttling back and fourth between sun and shade
Physiological: changes in peripheral blood flow
Give three reasons why an ectotherm might not regulate its body temperature
1) regulatory power may be limited
2) they are dependent on external heat sources
3) there may be costs associated with temperature regulation
What does Q10 represent?
An increase in metabolic rate for a 10 degree Celsius rise in body temperature in an ectotherm
Distinguish between acclimatization and acclimation.
Acclimatization are adjustments in behavior to regulate body temperature that occur in nature. When the adjustments are induced under laboratory conditions it is acclimation
Distinguish between hibernation and estivation and give examples of each.
Hibernation is a way of coping with extremely low temperatures by allowing body temperature to fall to those of its surroundings ie; bats, frogs, rodents. To estuvate is avoiding extremely high temperature or dry conditions ie; desert frogs.
Distinguish between freeze-resistance and freeze-tolerance.
Freeze-resistant: will not freeze, can survive it no problem
Freeze-tolerant: can tolerate it to a certain extent
Give two possible lethal consequences of high temperatures for living organisms
1) inactivation of enzymes
2) dehydration
What are thermophilic procaryotes and where to they live?
Heat tolerant organisms that live in hot springs where temperatures get close to the boiling point
In what habitat characterized by high temperatures and pressures might you find chemosynthetic bacteria?
hydrothermal vents
Provide a complete definition of the thermoneutral zone of an endotherm.
A range of temperatures over which an endothermic homeotherm can maintain a basal metabolic rate and which heat gain/loss can be adjusted by metabolically inexpensive means.
