15.2 - Thermoregulation in ectotherms Flashcards
Thermoregulation
Maintenance of a fairly regular core body temperature to maintain optimum enzyme activity
How to increase body temperature
Heat produced from cellular respiration
Conduction from surroundings
Convection from surroundings
Radiation from surroundings
How to decrease body temperature
Evaporation of water
Conduction to surroundings
Convection to surroundings
Radiation to surroundings
Radiation
Transmission of EM waves to and from the air, water and ground
Convection
Heating and cooling by currents of air/water
Warm air or water rises and cooler air or water sinks causing convection currents
Conduction
Heating as a result of the collision of molecules
Air is not a good conductor of heat, but ground and water are
Ectotherms
Use their surroundings to warm their bodies
Core temperature is heavily dependent on the environment
Examples of ectotherms
Invertebrate animals
Fish, amphibians, reptiles
Endotherms
Rely on metabolic processes to warm up and usually maintain a stable core temperature
Behavioural responses of ectotherms to increase body temperature
Contract muscles/vibrate
Exothermic body reactions
Bask in the sun
Maximise surface area exposed to the sun (extend body parts)
Conduction of heat from warm ground by pressing down bodies
Behavioural responses of ectotherms to decrease body temperature
Seek shade
Hide under rocks/stones
Digging burrows
Press bodies against cold surfaces
Minimise movements
Minimise body area exposed to skin
Physiological responses to temperature changes
Dark colours absorb more radiation than light colours
Altering heart rate to increase/decrease metabolic rate
Heat by heat exchange processes - cold blood from the skin takes up heat from blood flowing away from the core of the body
Secretion of mucus
During cold seasons, state of torpor is reached - slows metabolism
Release ice inhibiting compounds into bloodstream
