Adaptations to Heat

Question 1

How can heat death occur?

Answer 1

• Denatured enzymes
• Disruption of metabolic reactions (upsets biochemical balances)
• Changes in membrane structure

Question 2

Give an example of an organism capable of withstanding high ambient temps

Answer 2

Hydrothermal vent Pompeii worm
Withstand temps up to 105C

Question 3

Species that in habitat hot environments, secrete what on their skins?

Answer 3

Lipids to make them waterproof

Question 4

Once the preferred body temp is reached, what is secreted?

Answer 4

Water droplets from gland in skin to cool evaporatively

Question 5

Give an example of a behavioural method to avoid high temperatures

Answer 5

Burrowing

Question 6

Give an example of a morphological feature that benefits some animals in high temperatures

Answer 6

Thick fur & feathers

Question 7

Why are Bedouin goats predominantly black?

Answer 7

In winter, have metabolic rates 25% lower than White goats due to higher radiative heat load
- E.g. Need for food

Question 8

Why might colour not really important?

Answer 8

Easily altered by natural factors like wind & piloerection (raising fur & feathers)

Question 9

What animals tend to have short fur?

Answer 9

Those that rely on sweating

Question 10

What animals tend to have long fur?

Answer 10

Those that rely less on sweating & more on panting

Question 11

Give 4 different ways that water can be evaporated

Answer 11

• Sweating
• Panting
• Gular fluttering
• Insensitive cutaneous water loss

Question 12

What is adaptive hyperthermia?

Answer 12

Body temps rise during day as a consequence of heat storage, e.g. camels

Question 13

How is the brain kept cooler than the blood during periods of adaptive hypothermia?

Answer 13

• carotid arteries carrying blood to brain split into a series of capillaries (rete mirabile) in Venus sinus (circle of Willis)
• this carries blood from respiratory surface where evaporative cooling is taking place
• arterial blood is cooled before entering brain