15.2 - Thermoregulation in Ectotherms Flashcards
1
Q
Define thermoregulation.
A
Thermoregulation: Maintenance of relatively constant core temperature
2
Q
What are characteristics of ectotherms?
A
- 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
3
Q
What are charateristics of endotherms?
A
- Mammals and birds are endotherms
- They rely on metabolic processes to thermoregulate, despite the environmental temperature they tend to keep a stable core temperature
- They have adaptations to maintain body temperature
- Their metabolic rate is 5x that of ectotherms, so they must consume more food.
4
Q
What issue does an ectotherm face when thermoregulating?
A
- They cannot thermoregulate using metabolism – instead they have behavioural responses to thermoregulate
5
Q
What behavioural responses do ectotherms exhibit to thermoregulate?
A
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
6
Q
What physiological responses do ecotherms exhibit to warming?
A
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
