Summary Ectotherms

Ectotherms:


 An ectotherm is an organism that relies on external sources of
heat to regulate its body temperature. Metabolic reaction rates
cannot be increased to generate heat internally.
 So an ectotherm’s temperature changes in accordance with the
ambient temperature.
Advantages Disadvantages
Ectotherms use less of Individuals are less active in cooler
their food in respiration. temperatures and may need to warm
up I the morning before they can be
active – this puts them at greater risk
of predation.
Less food needs to be Individuals may not be capable of
found & individuals may activity in winter as they never warm
be able to survive long up sufficiently. This means that they
periods of time without must have sufficient stores of energy
eating. to survive winter without eating.
A greater proportion of
the energy obtained
from food can be used
for growth.


 Heat transfer between the body of an organism & its
environment depends on the size and direction of the
thermal gradient.
 Heat may be gained by conduction, convection & radiation.
 However heat can only be lost by evaporation (latent heat of
vaporisation).