ectotherms and endotherms Flashcards
definition of ectotherms
uses heat produced externally to maintain body temperature
ectotherms
not able to control body temp
rely on external sources of heat
temp fluctuates with external temp
use behavioural methods
definition of endotherms
uses heat produced internally to maintain body temperature
endotherms
mostly physiological methods e.g. respiration and vasodilation/vasoconstriction
some behavioural
behavioural responses of ectotherms to control body temperature
lie directly under sun, a arranging its body to maximise surface exposure -basking.
The surface on which they lie is
usually warm too.
This will quickly raise their body
temperature in the morning.
Once they are active, their muscle
contractions will generate some heat from increased respiration.
shelter in burrows to escape extremes of temperature
advantages of not controlling body temp physiologically
less food used in respiration to release energy
more energy gained from food can be converted to growth and increasing biomass
less food need to be found
can survive long periods of time without food
disadvantages of not controlling your internally body temperature physiologically
less active in cooler temperature
risk from predators
cannot take advantage of food that is available when they are cold
the importance of controlling body temperature
changes in body temperature can dramatically affect the activity of cell processes
When temperatures rise, molecules have more kinetic energy, so they collide more frequently
Chemical reactions therefore occur more quickly
The opposite is true in cooler conditions
Enzyme action may be affected if the active site is denatured by heat, and they lose their specific shape
The core temperature is the most important factor as vital organs are at the centre of the body
physiological process to control body temp
sweating
vasoconstriction/vasodilation
shivering
behavioural methods used by endotherms to control body temp
hibernation
migration
burrows
advantages of controlling your internal body temperature physiologically
maintain a fairly constant body temperature whatever the external temperature
Can remain active even when external temperatures are low
Inhabit colder parts of the planet
disadvantages of controlling your internal body temperature physiologically
Use a significant part of their energy intake to maintain body temperature in the cold
Lower proportion of the energy and nutrients gained from food is available for growth
Need to eat more food
May overheat in hot weather
