TEMPERATURE TALES --

TEMPERATURE TALES -- keeping warm, staying cool
Investigation of Temperature Regulation in Animals


Temperature Regulation - Thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different.
This process is one aspect of homeostasis: a dynamic state of stability between an animals internal environment and its external environment.
Potoroos
Long-nosed rat-kangaroo or potoroo (endotherm) – marsupial mammal 60cm long and 1kg in weight – lives mainly down east coast of Australia in forests and heath lands where there is relatively thick ground cover. It sleeps at day in a nest of vegetation and feeds at night digging for roots, fungi and insect larvae.
The breathing rate of potoroos was measured in response to changing air temperatures.
Method of heat loss
o Tail lacks hair
o Sweat glands were observed in dense rings around the tail
o At high temperatures, the tail appeared to be quite wet.
o At high temperatures, potoroos continually twitch tails from side to side

Potoroo cont.
Negative Feedback Loop
Potoroo's Body is in Homeostasis - not too hot and not too cold >>> Temperature increase is detected by thermoreceptors in the potoroo's body >>>> Control center inside the potoroo's body responds by producing sweat in the tail and then the tail flicks >>> body temperature of the Potoroo decreases because of sweat evaporation >>> potoroo's body returns to state of homeostasis
Endotherms and
Ectotherms
Endotherms:
(endo: inside; therm: temperature); generate their own body heat from the metabolic activities of cells.
Typically maintain constant body temperature.
Eg. Mammals and birds
Ectotherms:
(ecto: external); are unable to generate enough body heat from metabolic activities. They acquire most of the heat they need from external sources.
The body temperature of ectotherms fluctuates in line with environmental temperatures.
E.g. radiant heat from the sun, or heated conducted to their bodies from warm surfaces, such as rocks and earth. Animals such as fish amphibians and reptiles.