Lecture 21 - Thermal Exchange Flashcards
What is the primary determinant of species distribution
temperature
All organisms have ___________
optimal temperature range
Key determinant of biochemical reaction rates
Temperature
- > for every 10C decrease, reactions decrease 2x
Different types of thermal regulating organisms
Regulators
- > different temperature from environment
Conformer
- > same temperature as environment
Different types of body temperature
Homeothermic
- > constant temperature
Poikilothermic
- > variable body temperature
Different types of heat sources
Endothermic
- > primarily from metabolism
Ectothermic
- > primarily from environment
Living is ___________
energetically expensive
- > worse for endotherms, especially small ones
4 mechanisms of heat exchange
- radiation
- Evaporation
- Conduction
- Convection
thermal regulation
controlling heat exchange
thermal exchange is from _____________
high to low
Radiation
emission of electromagnetic waves by all objects warmer than absolute zero
- > physical and behavioural adaptations alter radiative exchange
Evaporation
it takes energy to evaporate water, so organisms lose heat with water
- > in terrestrial animals this occurs in skin and respiratory tissues
- > in plants this occurs through transpiration
conduction
direct transfer of heat between molecules of objects in contact
convection
transfer of heat by the movement of air or liquid past a surface
integuments role in heat exchange
integument (hair and feathers) traps air and increases boundary layer reducng convection (and reduces evaporation)
Thermal homeostasis
- > thermal regulators aim for thermal homeostasis
- > keeps internal conditions within “normal range” rather than an absolute set-point
- > some plants control flower temperature
