9.3

Question 1

Thermoregulation

Answer 1

The regulation of internal temperature by negative feedback mechanisms.
Thermoreceptors detect any deviations in the external and internal temperatures from an internal set point and then trigger behavioural and physiological responses that act to maintain the internal set point.
-Can adjust metabolism and rate of thermal energy exchange through the surface of the body.

Question 2

Mechanisms of thermal energy exchange

Answer 2

Almost all thermal energy exchange occurs at the surface where the body comes into contact with the external environment.
-Conduction: Flow of thermal energy b/w molecules in direct contact.
-Convection: Transfer of thermal energy
within a fluid (liquid or gas).
-Radiation: Transfer of thermal energy
by EM radiation.
-All animals exchange thermal energy through these four mechanisms (usually simultaneously).

Question 3

Homeotherms

Answer 3

Maintain a stable internal temperature, regardless of external conditions.
-Birds and mammals.

Question 4

Poikilotherms

Answer 4

Animals with a body temperature that varies considerably in response to external conditions.
-Fish, amphibians, reptiles, and invertebrates.

Question 5

Endotherm

Answer 5

Animals that are able to internally regulate their own body temperature by physiological processes.Endotherms are more successful than
ectotherms at maintaining a stable body
Temperature.
-Not necessarily more successful animals.
-Endotherms keep their bodies at optimal
temperature by regulating the amount of
thermal energy that is generated.

Question 6

Ectotherm

Answer 6

Animals that use behavioural mechanisms to
regulate their body temperature and absorb
thermal energy from their environment.

Question 7

Thermal Acclimatization

Answer 7

Thermal acclimatization refers to the adjustment of organisms to sustained temperature changes. This may be short term adapatation to ambient temperatures outside its normal range, but also includes adaptation to longer term variations such as with the seasons.

Question 8

Torpor

Answer 8

A short-term state of reduced metabolic rate and body temperature that reduces the demand for energy during the night or day.
-Bats, hummingbirds.

Question 9

Hibernation

Answer 9

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.
-Bears, Arctic ground squirrel.

Question 10

Estivation

Answer 10

A state of torpor that enables an animal to survive the summer by reducing the demand for energy.
-Lungfish, Toads, Frogs