5.1 - Communication and Homeostasis - Transferred Flashcards
What is an Ectotherm?
An organism that relies on external sources of heat to maintain body temperature
When an Ectotherm is TOO COLD, it will…
- Move into a sunny area
- Lie on a warm surface
- Expose a larger surface area to the sun/heat source
When an Ectotherm is TOO HOT, it will…
- Move out of the Sun
- Move underground
- Reduce body surface area exposed to the Sun
Give four examples of Ectotherms
- Snakes
- Locusts
- Lizards
- Horned Lizards
Snakes control body temperature by…
Bask in the Sun to directly absorb heat
Locusts control body temperature by…
- Increasing breathing rate when it gets hotter so more water evaporates
- Moving depending on the intensity of the Sun, controlling the amount of surface area exposed to the Sun
Lizards control body temperature by…
Hiding in burrows and crevices when it’s too hot
Horned Lizards control body temperature by…
Changing the shape of its ribcage, changing the amount of body exposed to the Sun
Advantages of Ectotherms
- Less food required for respiration
- More energy and nutrients can be used for growth
- Less food required in general, meaning they can survive for extended periods of time without food
Disadvantages of Ectotherms
- Less active when cold, meaning that they are more susceptible to predation and also means that they can’t take advantage of food available to them when they are cold
What is an Endotherm?
An organism that can produce its own body heat and therefore doesn’t rely on external heat sources
What does the temperature regulation mechanism in Endotherms rely on?
Effector in the skin and muscles
Where are many of the physiological adaptions involved in temperature regulation found?
In the skin
Why are many of the physiological adaptions involved in temperature regulation found in the skin?
Due to its contact with the external environment
Are there other organs involved in temperature regulation in Endotherms?
Yes
Give three examples of other organs involved in the temperature regulation mechanism in Endotherms
- Lungs
- Skeletal Muscles
- Blood vessels
How does the skin ‘react’ to an Endotherm being TOO HOT?
- Sweating increases
- Hair erector muscles relax
- Arteriole and Precapillary sphincters dilate
Why does an increase in sweating help when an Endotherm is TOO HOT?
Sweat evaporates using body heat as the latent heat of vapourisation, so reducing body heat
Why does the relaxation of hair erector muscles help when an Endotherm is TOO HOT?
When hair erector muscles relax, body hair lies flat, preventing an insulating layer of air from forming around the body, which traps heat
Why does the dilation of precapillary sphincters and arterioles help when an Endotherm is TOO HOT?
As more blood is directed to the skin, this allows excess body heat to be radiated away from the skin
How does the skin ‘react’ when an Endotherm is TOO COLD?
- Less sweating
- Hair erector muscles contract
- Vasoconstriction occurs
