Ecology- Temp and Water Variation

2 options for coping with environmental variation

tolerance and avoidance

study of interactions between organisms and physical environments that influence survival and persistence

physiological ecology

each species has range of environmental tolerances that determines

geographic distribution

physical environment influences ecological success in 2 ways

availability and tolerance limits

matches range of temps in which organisms live

• range of internal body temps the organism maintains

temp range of enzymes

adjusting to stress through behavior or physiology

• reversible

acclimatization

individuals with traits that enable them to cope with stress are favored

adaptation

populations with adaptations to unique environments

• eventual become separate species

ecotypes

as population adapts to particular set of environmental conditions, fitness in other environments reduce

principle of allocation

temp of organisms are determined by

external energy exchange

narrow temp ranges for optimal function

enzymes

regulate body temp through energy exchange with the external environment

ectotherms

rely on internal heat generation

endotherms

cost of endothermic

high demand for energy

range of environmental temps over which a constant basal metabolic rate can be maintained

thermoneutral zone

heat loss is greater then metabolic production

• body temp drops and metabolic heat generation increases

lower critical temp

surviving in cold climates by entering dormant state

torpor

endothermy evolution

feathers fur fat

water balance of organisms is determined by

external exchange of water and solutes

force that impedes water movement

resistance