Temperature regulation in ecotherms

Question 1

What are the limitations of ecotherms? How have they overcame this?

Answer 1

• ecotherms cannot control their body temperature using their metabolism
• they have developed a range of behavioural responses that enable them to overcome the limitations imposed by the temoerature of their surrounding

Question 2

How do ecotherms need to change their behavoir

Answer 2

• inscrease or reduce the radiation they absorb from the Sun.
• sometimes they need to warm up to reach a temp at which their metabolic reactions happen fast enough for them to be active
• or cool down to prevent their core temp reaching a point where enzymes begin to denature

Question 3

How do ecotherms increase radiation absorbtion

Answer 3

• bask in the sun
• orientate their bodies so that the maximum surface area is exposed to the sun
  
  • even extend areas of their bodies to increase the SA
• pressing body against the warm ground
• exothermic metabolic reactions
  
  • butterflies may vibratre their wings to warm their muscles before they take flight

Question 4

How do ecotherms cool?

Answer 4

• many warming prcesses are reversed
• shelter from sun by seeking shade
  
  • even digging burrows
• they will press their bodies against cool, shady earth or stones
• or move into mud or water
• minimum sufrace area is exposed
• minimise movements to reduce the metabolic heat generatued

Question 5

What are the physiological responses to warming?>

Answer 5

• dark colour
  
  • absorbs more radiation
  • lizards living in colder climates tend to be darker
• alter heart rate to increase or decrease the metabolic rate and sometimes to affect the warming or cooling across body surfaces

Question 6

How is the Namaqua chamelon adapted for the morning

Answer 6

• black in the morning
  
  • may even appear black on the side exposed to the sun and pale grey on the other side of the body
• orientates body sideways to sun
• increased heart rate early in the morning when basking
• inflates body early in the morning
• presses body against sasnd in the morning

Question 7

How is the namqua chamelon adapted for the day?

Answer 7

• during the day it delates its body
• animal becomes vbery grey
• holds itself aweay from the desert surface
• heart rate slows down
• open its mouth and pants