Australian ectotherms and endotherms
A- TYPES OF TEMPERATURE REGULATION
1- The cat, human and platypus could be described as true endotherms, as they all maintain a relatively constant internal body temperature that is independent of the external temperature. As the environmental temperature rises from 5C to 40C, the humans body temperature remains constant, the cat's and the platypus' increases by around 3Ã¢ÂÂ«C.
2- The lizard and echidna are ectotherms as their body temperature fluctuates according to the temperature of the external environment. The lizard's body temperature rises by 25C and the echidna by 10C as the external temp rises.
3- All animals are either clearly ectotherms or endotherms apart from the echidna. Although the body temperature of this animal increases with the external temperature, it does not increase as clearly as the lizard's. An explanation for this could be that the echidna maintains a higher level of ability to control over internal temperature than the lizard, which has a very limited ability to do so.
4- All enzymes and other molecules function within a limited temperature range. Unless the body temperature is maintained at these optimal conditions, the rate of enzyme-catalysed reactions decreases and the organism will not function properly.
B- SOME METHODS OF MAMMALIAN TEMPERATURE REGULATION
Observation Explanation Type of adaptation
Echidna's living in cold regions hibernate during the winter Hibernation is used to keep the animal's body temperature constantly warm by removing itself from the cold environment Behavioural
Your skin often looks quite flushed on a hot day This is due to the vasodilation of arterioles Physiological
Many Australian marsupials salivate and lick their fur on hot days Saliva is used as a way to cool down, much like sweating Behavioural
Whales have a thick layer of blubber under skin This layer provides insulation from the cold water...