15.2 Thermoregulation in ecotherms

Question 1

Behavioural responses of ectotherms to thermorégulate

Answer 1

The responses increase or reduce the radiation absorbed from the sun

They bask in the sun to gain enough heat to make their metabolic reactions happen fast enough for them to be active (e.g. lizards bathe in the sun, get energy, and go hunting)
They also increase body temperature by pressing their body against the warm ground
To cool down (sometimes to a point where enzymes denature), they hide from the sun (shelter), they press their bodies against cool surfaces
Insects flap wings to generate heat in wing muscles before flying

Question 2

Physiological responses to thermoregulate

Answer 2

Dark colours absorb more radiation than light ones, lizards that live in colder climates are darker than those in hotter countries, therefore they get warmer.
Ectotherms alter their heart rate to increase/decrease metabolic rate affecting cooling/heating

Question 3

What issue do ectotherms face when thermoregulating

Answer 3

They cannot thermoregulate using metabolism – instead they have behavioural responses to thermoregulate

Question 4

Define thermoregulation

Answer 4

Maintenance of relatively constant core temperature

Question 5

Characteristics of ectotherms

Answer 5

Their core body temperature is dependant on the environment
Includes all invertebrates, fish, amphibians and reptiles
Aquatic ectotherms do not need to thermoregulate due to the high heat capacity of water (temperature doesn’t change much)
Land bound ectotherms struggle to thermoregulate