9.3 Thermoregulation Flashcards
Thermoregulation
The regulation of internal temp by negative feedback mechanisms
Homeotherm
An animal that maintains a stable body temp regardless of temp of external environment
Poikilotherm
An animal whose body temp varies with, and often matches, the temp of the external environment
Torpor
A short-term state of reduced metabolic rate and body temp that reduces the demand for energy during the night or day
Estivation
A state of torpor that enables an animal to survive the summer by reducing the demand for energy
Ectotherm
An animal that maintains its body temp by absorbing themal energy from the environment
Endotherm
An animal that maintains its body temp by internal mechanisms
Thermal acclimatization
Process by which an animal gradually adjusts to temp changes in its environment
Hibernation
A state of greatly reduced metabolic rate and activity that enables an animal to survive the winter by reducing the demand for energy when food is unavailable
Thermoregulation
Maintenance of body temps within a range that enables cells to function properly
Mechanisms of Thermal Energy Exchange
- Animals absorb energy if they’re cooler
than external environment and release thermal energy if they’re warmer
than their environment - Energy exchange can occur through
conduction, convection, radiation, and
evaporation
Homeotherms and Poikilotherms
These terms describe what happens to an
organism’s internal temperature
Poikilotherms:
body temperature varies
with the environment
Homeotherms:
maintain a stable body
temperature regardless of the environment
Endotherm
Maintain a
constant internal temp
by generating heat through an increase in cellular respiration
Ectotherm
use external (environmental) mechanisms to control their temperature (ex.
Fish, Reptiles, Insects etc.)
Most endotherms are
homeotherms
Most ectotherms
are poikilotherms
As water freezes it forms
sharp ice crystals which
rupture cell walls
Water also expands
when frozen and when
this occurs in an
organism it can
destroy many important body tissues
Torpor:
Daily/nightly periods of decreased
physiological activity resulting in lowered
metabolism and temps to conserve energy
- eg. Some birds, marsupials, mammals such as
rodents and bats
So how do wood frogs survive being frozen?
They produce antifreeze within cells to prevent freezing
(Glucose)
- They also dehydrate cells to prevent ice from forming
Hibernation:
Torpor occurring over an
extended period (weeks/months) during winter
Estivation:
Torpor occurring over an extended
period during summer
