topic 10 - homeostasis: thermoregulation

Q10 equation

RT/(RT-10)

Q10=1

Not temperature sensitive

Q10 = 2

Indicates a doubling of reaction with each increase in temperature by 10 degrees

Ectotherm

Primarily rely on heat generated from external sources

ie. reptiles, amphibians, fish

Endotherm

Produce heat internally

Homeothermic

Body temperature remains stable

Heterothermic

Body temperature fluctuates

Metabolism of homeothermic endotherms

Metabolic rate is high and constant to support continuous heat production; high energy demand (must enact frequently) ie. hamsters, mouse

Metabolism of heterothermic ectotherms

Metabolic rate is variable; usually low, but can increase during active periods or short-term endothermic. Low energy demand overall (less food needed)

ie. snake heating up eggs, short term endothermic

Thermoconductance

Losing of heat from organism. Determined by the size and shape of the animals and the thickness of any layers of insulation.

High thermal conductance

Heat is loss is easy (poor insulation)

Low thermal conductance

Heat is retained well (better insulation)

Relationship b/w thermal conductance and metabolism

The steeper the relationship between metabolism and temp becomes, more correlation. ie. the higher the heat loss (thermal conductance), the higher the metabolism

Thermoneutral zone

Not too hot not too cold

Basal metabolic rate (BMR)

Measures the minimum energy an organism needs to stay alive - applies to endothermic animals (eg mammals, birds).

Measured when the animal is at rest, in a fasted state, in its themoneutral zone, not stressed or active.

Represents the energy needed to maintain essential functions like breathing, circulation, and temperature regulation.

Standard Metabolic Rate (SMR)

Measures of the minimum energy an organism needs to stay alive. Applies to ectotherm animals (eg reptiles, amphibians, fish).

Measured under similar conditions as BMR, at rest, in a fasted state, at a specific body temperature (since ectotherms rely on the environment for heat).

Ectotherms don’t maintain a constant body temperature, SMR varies depending on ambient temperature.

Which animal has greater metabolic rate, 120g fish or 100g rabbit?

100g rabbit

Rabbit is an endotherm, must maintain a constant internal body temperature, requires more energy even at rest.

Fish is ectotherm, relies on external temperatures to regulate body heat, uses less energy to stay alive.

Even though fish is slightly heavier, endotherm always have higher metabolic rate per gram of body mass then ectotherm of similar size